CWE nodes in this view (graph) are associated with the OWASP Top Ten, as released in 2007. This view is considered obsolete as a newer version of the OWASP Top Ten is available.
Audience
Stakeholder
Description
Software Developers
This view outlines the most important issues as identified by the OWASP Top Ten (2007 version), providing a good starting point for web application developers who want to code more securely.
Product Customers
This view outlines the most important issues as identified by the OWASP Top Ten (2007 version), providing customers with a way of asking their software developers to follow minimum expectations for secure code.
Educators
Since the OWASP Top Ten covers the most frequently encountered issues, this view can be used by educators as training material for students.
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.
629 (Weaknesses in OWASP Top Ten (2007)) > 712 (OWASP Top Ten 2007 Category A1 - Cross Site Scripting (XSS))
Weaknesses in this category are related to the A1 category in the OWASP Top Ten 2007.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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)
629 (Weaknesses in OWASP Top Ten (2007)) > 712 (OWASP Top Ten 2007 Category A1 - Cross Site Scripting (XSS)) > 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
629 (Weaknesses in OWASP Top Ten (2007)) > 713 (OWASP Top Ten 2007 Category A2 - Injection Flaws)
Weaknesses in this category are related to the A2 category in the OWASP Top Ten 2007.
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)
629 (Weaknesses in OWASP Top Ten (2007)) > 713 (OWASP Top Ten 2007 Category A2 - Injection Flaws) > 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.Command 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 Special Elements used in an SQL Command ('SQL Injection') - (89)
629 (Weaknesses in OWASP Top Ten (2007)) > 713 (OWASP Top Ten 2007 Category A2 - Injection Flaws) > 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. 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.SQL injectionSQLi
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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)
629 (Weaknesses in OWASP Top Ten (2007)) > 713 (OWASP Top Ten 2007 Category A2 - Injection Flaws) > 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.XML Injection (aka Blind XPath Injection) - (91)
629 (Weaknesses in OWASP Top Ten (2007)) > 713 (OWASP Top Ten 2007 Category A2 - Injection Flaws) > 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.Improper Neutralization of CRLF Sequences ('CRLF Injection') - (93)
629 (Weaknesses in OWASP Top Ten (2007)) > 713 (OWASP Top Ten 2007 Category A2 - Injection Flaws) > 93 (Improper Neutralization of CRLF Sequences ('CRLF Injection'))
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
629 (Weaknesses in OWASP Top Ten (2007)) > 714 (OWASP Top Ten 2007 Category A3 - Malicious File Execution)
Weaknesses in this category are related to the A3 category in the OWASP Top Ten 2007.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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)
629 (Weaknesses in OWASP Top Ten (2007)) > 714 (OWASP Top Ten 2007 Category A3 - Malicious File Execution) > 434 (Unrestricted Upload of File with Dangerous Type)
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.Unrestricted File Upload
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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)
629 (Weaknesses in OWASP Top Ten (2007)) > 714 (OWASP Top Ten 2007 Category A3 - Malicious File Execution) > 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 metacharactersOS Command Injection
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.Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') - (95)
629 (Weaknesses in OWASP Top Ten (2007)) > 714 (OWASP Top Ten 2007 Category A3 - Malicious File Execution) > 95 (Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection'))
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").
629 (Weaknesses in OWASP Top Ten (2007)) > 714 (OWASP Top Ten 2007 Category A3 - Malicious File Execution) > 98 (Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion'))
The PHP application receives input from an upstream component, but it does not restrict or incorrectly restricts the input before its usage in "require," "include," or similar functions.Remote file includeRFILocal file inclusion
629 (Weaknesses in OWASP Top Ten (2007)) > 715 (OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference)
Weaknesses in this category are related to the A4 category in the OWASP Top Ten 2007.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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)
629 (Weaknesses in OWASP Top Ten (2007)) > 715 (OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference) > 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
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.External Control of Assumed-Immutable Web Parameter - (472)
629 (Weaknesses in OWASP Top Ten (2007)) > 715 (OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference) > 472 (External Control of Assumed-Immutable Web Parameter)
The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields.Assumed-Immutable Parameter 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.Authorization Bypass Through User-Controlled Key - (639)
629 (Weaknesses in OWASP Top Ten (2007)) > 715 (OWASP Top Ten 2007 Category A4 - Insecure Direct Object Reference) > 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
629 (Weaknesses in OWASP Top Ten (2007)) > 716 (OWASP Top Ten 2007 Category A5 - Cross Site Request Forgery (CSRF))
Weaknesses in this category are related to the A5 category in the OWASP Top Ten 2007.
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.Cross-Site Request Forgery (CSRF) - (352)
629 (Weaknesses in OWASP Top Ten (2007)) > 716 (OWASP Top Ten 2007 Category A5 - Cross Site Request Forgery (CSRF)) > 352 (Cross-Site Request Forgery (CSRF))
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.Session RidingCross Site Reference ForgeryXSRF
629 (Weaknesses in OWASP Top Ten (2007)) > 717 (OWASP Top Ten 2007 Category A6 - Information Leakage and Improper Error Handling)
Weaknesses in this category are related to the A6 category in the OWASP Top Ten 2007.
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.Exposure of Sensitive Information to an Unauthorized Actor - (200)
629 (Weaknesses in OWASP Top Ten (2007)) > 717 (OWASP Top Ten 2007 Category A6 - Information Leakage and Improper Error Handling) > 200 (Exposure of Sensitive Information to an Unauthorized Actor)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.Information DisclosureInformation Leak
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Observable Discrepancy - (203)
629 (Weaknesses in OWASP Top Ten (2007)) > 717 (OWASP Top Ten 2007 Category A6 - Information Leakage and Improper Error Handling) > 203 (Observable Discrepancy)
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not.Side Channel Attack
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Generation of Error Message Containing Sensitive Information - (209)
629 (Weaknesses in OWASP Top Ten (2007)) > 717 (OWASP Top Ten 2007 Category A6 - Information Leakage and Improper Error Handling) > 209 (Generation of Error Message Containing Sensitive Information)
The product generates an error message that includes sensitive information about its environment, users, or associated data.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.Insertion of Sensitive Information Into Debugging Code - (215)
629 (Weaknesses in OWASP Top Ten (2007)) > 717 (OWASP Top Ten 2007 Category A6 - Information Leakage and Improper Error Handling) > 215 (Insertion of Sensitive Information Into Debugging Code)
The product inserts sensitive information into debugging code, which could expose this information if the debugging code is not disabled in production.
629 (Weaknesses in OWASP Top Ten (2007)) > 718 (OWASP Top Ten 2007 Category A7 - Broken Authentication and Session Management)
Weaknesses in this category are related to the A7 category in the OWASP Top Ten 2007.
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 Authentication - (287)
629 (Weaknesses in OWASP Top Ten (2007)) > 718 (OWASP Top Ten 2007 Category A7 - Broken Authentication and Session Management) > 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.Reflection Attack in an Authentication Protocol - (301)
629 (Weaknesses in OWASP Top Ten (2007)) > 718 (OWASP Top Ten 2007 Category A7 - Broken Authentication and Session Management) > 301 (Reflection Attack in an Authentication Protocol)
Simple authentication protocols are subject to reflection attacks if a malicious user can use the target machine to impersonate a trusted user.
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.Insufficiently Protected Credentials - (522)
629 (Weaknesses in OWASP Top Ten (2007)) > 718 (OWASP Top Ten 2007 Category A7 - Broken Authentication and Session Management) > 522 (Insufficiently Protected Credentials)
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
629 (Weaknesses in OWASP Top Ten (2007)) > 719 (OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage)
Weaknesses in this category are related to the A8 category in the OWASP Top Ten 2007.
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.Missing Encryption of Sensitive Data - (311)
629 (Weaknesses in OWASP Top Ten (2007)) > 719 (OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage) > 311 (Missing Encryption of Sensitive Data)
The product does not encrypt sensitive or critical information before storage or transmission.
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.Use of Hard-coded Cryptographic Key - (321)
629 (Weaknesses in OWASP Top Ten (2007)) > 719 (OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage) > 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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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 Cryptographic Step - (325)
629 (Weaknesses in OWASP Top Ten (2007)) > 719 (OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage) > 325 (Missing Cryptographic Step)
The product does not implement a required step in a cryptographic algorithm, resulting in weaker encryption than advertised by the algorithm.
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.Inadequate Encryption Strength - (326)
629 (Weaknesses in OWASP Top Ten (2007)) > 719 (OWASP Top Ten 2007 Category A8 - Insecure Cryptographic Storage) > 326 (Inadequate Encryption Strength)
The product stores or transmits sensitive data using an encryption scheme that is theoretically sound, but is not strong enough for the level of protection required.
629 (Weaknesses in OWASP Top Ten (2007)) > 720 (OWASP Top Ten 2007 Category A9 - Insecure Communications)
Weaknesses in this category are related to the A9 category in the OWASP Top Ten 2007.
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.Missing Encryption of Sensitive Data - (311)
629 (Weaknesses in OWASP Top Ten (2007)) > 720 (OWASP Top Ten 2007 Category A9 - Insecure Communications) > 311 (Missing Encryption of Sensitive Data)
The product does not encrypt sensitive or critical information before storage or transmission.
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.Use of Hard-coded Cryptographic Key - (321)
629 (Weaknesses in OWASP Top Ten (2007)) > 720 (OWASP Top Ten 2007 Category A9 - Insecure Communications) > 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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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 Cryptographic Step - (325)
629 (Weaknesses in OWASP Top Ten (2007)) > 720 (OWASP Top Ten 2007 Category A9 - Insecure Communications) > 325 (Missing Cryptographic Step)
The product does not implement a required step in a cryptographic algorithm, resulting in weaker encryption than advertised by the algorithm.
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.Inadequate Encryption Strength - (326)
629 (Weaknesses in OWASP Top Ten (2007)) > 720 (OWASP Top Ten 2007 Category A9 - Insecure Communications) > 326 (Inadequate Encryption Strength)
The product stores or transmits sensitive data using an encryption scheme that is theoretically sound, but is not strong enough for the level of protection required.
629 (Weaknesses in OWASP Top Ten (2007)) > 721 (OWASP Top Ten 2007 Category A10 - Failure to Restrict URL Access)
Weaknesses in this category are related to the A10 category in the OWASP Top Ten 2007.
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 Authorization - (285)
629 (Weaknesses in OWASP Top Ten (2007)) > 721 (OWASP Top Ten 2007 Category A10 - Failure to Restrict URL Access) > 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
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection 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)
629 (Weaknesses in OWASP Top Ten (2007)) > 721 (OWASP Top Ten 2007 Category A10 - Failure to Restrict URL Access) > 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.Direct Request ('Forced Browsing') - (425)
629 (Weaknesses in OWASP Top Ten (2007)) > 721 (OWASP Top Ten 2007 Category A10 - Failure to Restrict URL Access) > 425 (Direct Request ('Forced Browsing'))
The web application does not adequately enforce appropriate authorization on all restricted URLs, scripts, or files.forced browsing
(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.
Notes
Relationship
The relationships in this view are a direct extraction of the CWE mappings that are in the 2007 OWASP document. CWE has changed since the release of that document.
CWE-288: Authentication Bypass Using an Alternate Path or Channel
Weakness ID: 288
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:
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Description
A product requires authentication, but the product has an alternate path or channel that does not require authentication.
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
Access Control
Technical Impact: Bypass Protection Mechanism
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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 "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.
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
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
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)
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.
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.
Router allows remote attackers to read system logs without authentication by directly connecting to the login screen and typing certain control characters.
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.
User can avoid lockouts by using an API instead of the GUI to conduct brute force password guessing.
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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.
CWE-639: Authorization Bypass Through User-Controlled Key
Weakness ID: 639
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.
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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.
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
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.
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.
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
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.
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.
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 "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.
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 "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.
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 "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.
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 "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.
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
Architecture and Design
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
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)
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.
An educational application does not appropriately restrict file IDs to a particular user. The attacker can brute-force guess IDs, indicating IDOR.
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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.
Weakness ID: 352 (Structure: Composite)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.
Vulnerability Mapping:
ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities
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.
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Description
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.
Composite Components
Nature
Type
ID
Name
Requires
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.
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
When a web server is designed to receive a request from a client without any mechanism for verifying that it was intentionally sent, then it might be possible for an attacker to trick a client into making an unintentional request to the web server which will be treated as an authentic request. This can be done via a URL, image load, XMLHttpRequest, etc. and can result in exposure of data or unintended code execution.
Alternate Terms
Session Riding
Cross Site Reference Forgery
XSRF
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
Confidentiality Integrity Availability Non-Repudiation Access Control
Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism; Read Application Data; Modify Application Data; DoS: Crash, Exit, or Restart
The consequences will vary depending on the nature of the functionality that is vulnerable to CSRF. An attacker could effectively perform any operations as the victim. If the victim is an administrator or privileged user, the consequences may include obtaining complete control over the web application - deleting or stealing data, uninstalling the product, or using it to launch other attacks against all of the product's users. Because the attacker has the identity of the victim, the scope of CSRF is limited only by the victim's privileges.
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, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330]
Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
Phase: Implementation
Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
Phase: Architecture and Design
Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330). [REF-332]
Note: Note that this can be bypassed using XSS (CWE-79).
Phase: Architecture and Design
Identify especially dangerous operations. When the user performs a dangerous operation, send a separate confirmation request to ensure that the user intended to perform that operation.
Note: Note that this can be bypassed using XSS (CWE-79).
Phase: Architecture and Design
Use the "double-submitted cookie" method as described by Felten and Zeller:
When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user's machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same.
Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult.
This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]
Note: Note that this can probably be bypassed using XSS (CWE-79), or when using web technologies that enable the attacker to read raw headers from HTTP requests.
Phase: Architecture and Design
Do not use the GET method for any request that triggers a state change.
Phase: Implementation
Check the HTTP Referer header to see if the request originated from an expected page. This could break legitimate functionality, because users or proxies may have disabled sending the Referer for privacy reasons.
Note: Note that this can be bypassed using XSS (CWE-79). An attacker could use XSS to generate a spoofed Referer, or to generate a malicious request from a page whose Referer would be allowed.
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
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
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 "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.
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 "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.
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
Architecture and Design
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
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)
Technologies
Web Server (Undetermined Prevalence)
Likelihood Of Exploit
Medium
Demonstrative Examples
Example 1
This example PHP code attempts to secure the form submission process by validating that the user submitting the form has a valid session. A CSRF attack would not be prevented by this countermeasure because the attacker forges a request through the user's web browser in which a valid session already exists.
The following HTML is intended to allow a user to update a profile.
// initiate the session in order to validate sessions
session_start();
//if the session is registered to a valid user then allow update
if (! session_is_registered("username")) {
echo "invalid session detected!";
// Redirect user to login page [...]
exit;
}
// The user session is valid, so process the request
// and update the information
update_profile();
function update_profile {
// read in the data from $POST and send an update
// to the database SendUpdateToDatabase($_SESSION['username'], $_POST['email']); [...] echo "Your profile has been successfully updated.";
}
This code may look protected since it checks for a valid session. However, CSRF attacks can be staged from virtually any tag or HTML construct, including image tags, links, embed or object tags, or other attributes that load background images.
The attacker can then host code that will silently change the username and email address of any user that visits the page while remaining logged in to the target web application. The code might be an innocent-looking web page such as:
(attack code)
Example Language: HTML
<SCRIPT> function SendAttack () {
form.email = "attacker@example.com"; // send to profile.php form.submit();
Notice how the form contains hidden fields, so when it is loaded into the browser, the user will not notice it. Because SendAttack() is defined in the body's onload attribute, it will be automatically called when the victim loads the web page.
Assuming that the user is already logged in to victim.example.com, profile.php will see that a valid user session has been established, then update the email address to the attacker's own address. At this stage, the user's identity has been compromised, and messages sent through this profile could be sent to the attacker's address.
web interface allows password changes or stopping a virtual machine via CSRF
Detection Methods
Manual 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.
Specifically, manual analysis can be useful for finding this weakness, and for minimizing false positives assuming an understanding of business logic. However, it might not achieve desired code coverage within limited time constraints. For black-box analysis, if credentials are not known for privileged accounts, then the most security-critical portions of the application may not receive sufficient attention.
Consider using OWASP CSRFTester to identify potential issues and aid in 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
CSRF is currently difficult to detect reliably using automated techniques. This is because each application has its own implicit security policy that dictates which requests can be influenced by an outsider and automatically performed on behalf of a user, versus which requests require strong confidence that the user intends to make the request. For example, a keyword search of the public portion of a web site is typically expected to be encoded within a link that can be launched automatically when the user clicks on the link.
Effectiveness: Limited
Automated Static Analysis - Binary or Bytecode
According to SOAR, the following detection techniques may be useful:
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).
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).
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).
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).
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).
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).
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).
(this CWE ID could be used to map to real-world vulnerabilities)
Reason: Other
Rationale:
This is a well-known Composite of multiple weaknesses that must all occur simultaneously, although it is attack-oriented in nature.
Comments:
While attack-oriented composites are supported in CWE, they have not been a focus of research. There is a chance that future research or CWE scope clarifications will change or deprecate them. Perform root-cause analysis to determine if other weaknesses allow CSRF attacks to occur, and map to those weaknesses. For example, predictable CSRF tokens might allow bypass of CSRF protection mechanisms; if this occurs, they might be better characterized as randomness/predictability weaknesses.
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.
Theoretical
The CSRF topology is multi-channel:
Attacker (as outsider) to intermediary (as user). The interaction point is either an external or internal channel.
Intermediary (as user) to server (as victim). The activation point is an internal channel.
[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 37. McGraw-Hill. 2010.
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.
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Description
The web application does not adequately enforce appropriate authorization on all restricted URLs, scripts, or files.
Extended Description
Web applications susceptible to direct request attacks often make the false assumption that such resources can only be reached through a given navigation path and so only apply authorization at certain points in the path.
Alternate Terms
forced browsing:
The "forced browsing" term could be misinterpreted to include weaknesses such as CSRF or XSS, so its use is discouraged.
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
Confidentiality Integrity Availability Access Control
Technical Impact: Read Application Data; Modify Application Data; Execute Unauthorized Code or Commands; Gain Privileges or Assume Identity
Potential Mitigations
Phases: Architecture and Design; Operation
Apply appropriate access control authorizations for each access to all restricted URLs, scripts or files.
Phase: Architecture and Design
Consider using MVC based frameworks such as Struts.
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.
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.
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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 "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.
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 "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.
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
Operation
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)
Technologies
Class: Web Based (Undetermined Prevalence)
Demonstrative Examples
Example 1
If forced browsing is possible, an attacker may be able to directly access a sensitive page by entering a URL similar to the following.
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.
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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.
Notes
Relationship
Overlaps Modification of Assumed-Immutable Data (MAID), authorization errors, container errors; often primary to other weaknesses such as XSS and SQL injection.
Theoretical
"Forced browsing" is a step-based manipulation involving the omission of one or more steps, whose order is assumed to be immutable. The application does not verify that the first step was performed successfully before the second step. The consequence is typically "authentication bypass" or "path disclosure," although it can be primary to all kinds of weaknesses, especially in languages such as PHP, which allow external modification of assumed-immutable variables.
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Weakness ID: 200
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:
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.
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Description
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
Extended Description
There are many different kinds of mistakes that introduce information exposures. The severity of the error can range widely, depending on the context in which the product operates, the type of sensitive information that is revealed, and the benefits it may provide to an attacker. Some kinds of sensitive information include:
private, personal information, such as personal messages, financial data, health records, geographic location, or contact details
system status and environment, such as the operating system and installed packages
business secrets and intellectual property
network status and configuration
the product's own code or internal state
metadata, e.g. logging of connections or message headers
indirect information, such as a discrepancy between two internal operations that can be observed by an outsider
Information might be sensitive to different parties, each of which may have their own expectations for whether the information should be protected. These parties include:
the product's own users
people or organizations whose information is created or used by the product, even if they are not direct product users
the product's administrators, including the admins of the system(s) and/or networks on which the product operates
the developer
Information exposures can occur in different ways:
the code explicitly inserts sensitive information into resources or messages that are intentionally made accessible to unauthorized actors, but should not contain the information - i.e., the information should have been "scrubbed" or "sanitized"
a different weakness or mistake indirectly inserts the sensitive information into resources, such as a web script error revealing the full system path of the program.
the code manages resources that intentionally contain sensitive information, but the resources are unintentionally made accessible to unauthorized actors. In this case, the information exposure is resultant - i.e., a different weakness enabled the access to the information in the first place.
It is common practice to describe any loss of confidentiality as an "information exposure," but this can lead to overuse of CWE-200 in CWE mapping. From the CWE perspective, loss of confidentiality is a technical impact that can arise from dozens of different weaknesses, such as insecure file permissions or out-of-bounds read. CWE-200 and its lower-level descendants are intended to cover the mistakes that occur in behaviors that explicitly manage, store, transfer, or cleanse sensitive information.
Alternate Terms
Information Disclosure:
This term is frequently used in vulnerability advisories to describe a consequence or technical impact, for any vulnerability that has a loss of confidentiality. Often, CWE-200 can be misused to represent the loss of confidentiality, even when the mistake - i.e., the weakness - is not directly related to the mishandling of the information itself, such as an out-of-bounds read that accesses sensitive memory contents; here, the out-of-bounds read is the primary weakness, not the disclosure of the memory. In addition, this phrase is also used frequently in policies and legal documents, but it does not refer to any disclosure of security-relevant information.
Information Leak:
This is a frequently used term, however the "leak" term has multiple uses within security. In some cases it deals with the accidental exposure of information from a different weakness, but in other cases (such as "memory leak"), this deals with improper tracking of resources, which can lead to exhaustion. As a result, CWE is actively avoiding usage of the "leak" term.
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
Confidentiality
Technical Impact: Read Application Data
Potential Mitigations
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.
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
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)
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).
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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
Architecture and Design
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)
Technologies
Class: Mobile (Undetermined Prevalence)
Likelihood Of Exploit
High
Demonstrative Examples
Example 1
The following code checks validity of the supplied username and password and notifies the user of a successful or failed login.
(bad code)
Example Language: Perl
my $username=param('username');
my $password=param('password');
if (IsValidUsername($username) == 1)
{
if (IsValidPassword($username, $password) == 1)
{
print "Login Successful";
}
else
{
print "Login Failed - incorrect password";
}
}
else
{
print "Login Failed - unknown username";
}
In the above code, there are different messages for when an incorrect username is supplied, versus when the username is correct but the password is wrong. This difference enables a potential attacker to understand the state of the login function, and could allow an attacker to discover a valid username by trying different values until the incorrect password message is returned. In essence, this makes it easier for an attacker to obtain half of the necessary authentication credentials.
While this type of information may be helpful to a user, it is also useful to a potential attacker. In the above example, the message for both failed cases should be the same, such as:
(result)
"Login Failed - incorrect username or password"
Example 2
This code tries to open a database connection, and prints any exceptions that occur.
(bad code)
Example Language: PHP
try {
openDbConnection();
} //print exception message that includes exception message and configuration file location catch (Exception $e) {
If an exception occurs, the printed message exposes the location of the configuration file the script is using. An attacker can use this information to target the configuration file (perhaps exploiting a Path Traversal weakness). If the file can be read, the attacker could gain credentials for accessing the database. The attacker may also be able to replace the file with a malicious one, causing the application to use an arbitrary database.
Example 3
In the example below, the method getUserBankAccount retrieves a bank account object from a database using the supplied username and account number to query the database. If an SQLException is raised when querying the database, an error message is created and output to a log file.
(bad code)
Example Language: Java
public BankAccount getUserBankAccount(String username, String accountNumber) {
query = "SELECT * FROM accounts WHERE owner = " + username + " AND accountID = " + accountNumber; DatabaseManager dbManager = new DatabaseManager(); Connection conn = dbManager.getConnection(); Statement stmt = conn.createStatement(); ResultSet queryResult = stmt.executeQuery(query); userAccount = (BankAccount)queryResult.getObject(accountNumber);
}
} catch (SQLException ex) {
String logMessage = "Unable to retrieve account information from database,\nquery: " + query; Logger.getLogger(BankManager.class.getName()).log(Level.SEVERE, logMessage, ex);
} return userAccount;
}
The error message that is created includes information about the database query that may contain sensitive information about the database or query logic. In this case, the error message will expose the table name and column names used in the database. This data could be used to simplify other attacks, such as SQL injection (CWE-89) to directly access the database.
Example 4
This code stores location information about the current user:
(bad code)
Example Language: Java
locationClient = new LocationClient(this, this, this); locationClient.connect(); currentUser.setLocation(locationClient.getLastLocation()); ...
catch (Exception e) {
AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setMessage("Sorry, this application has experienced an error."); AlertDialog alert = builder.create(); alert.show(); Log.e("ExampleActivity", "Caught exception: " + e + " While on User:" + User.toString());
}
When the application encounters an exception it will write the user object to the log. Because the user object contains location information, the user's location is also written to the log.
Example 5
The following is an actual MySQL error statement:
(result)
Example Language: SQL
Warning: mysql_pconnect(): Access denied for user: 'root@localhost' (Using password: N1nj4) in /usr/local/www/wi-data/includes/database.inc on line 4
The error clearly exposes the database credentials.
Example 6
This code displays some information on a web page.
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:
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.
Product sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.
Version control system allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.
Virtual machine allows malicious web site operators to determine the existence of files on the client by measuring delays in the execution of the getSystemResource method.
Composite: application running with high privileges (CWE-250) allows user to specify a restricted file to process, which generates a parsing error that leaks the contents of the file (CWE-209).
Collaboration platform does not clear team emails in a response, allowing leak of email addresses
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)
Developers may insert sensitive information that they do not believe, or they might forget to remove the sensitive information after it has been processed
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)
Separate mistakes or weaknesses could inadvertently make the sensitive information available to an attacker, such as in a detailed error message that can be read by an unauthorized party
Detection Methods
Automated Static Analysis - Binary or Bytecode
According to SOAR, the following detection techniques may be useful:
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).
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).
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).
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).
(this CWE ID should not be used to map to real-world vulnerabilities)
Reason: Frequent Misuse
Rationale:
CWE-200 is commonly misused to represent the loss of confidentiality in a vulnerability, but confidentiality loss is a technical impact - not a root cause error. As of CWE 4.9, over 400 CWE entries can lead to a loss of confidentiality. Other options are often available. [REF-1287].
Comments:
If an error or mistake causes information to be disclosed, then use the CWE ID for that error. Consider starting with improper authorization (CWE-285), insecure permissions (CWE-732), improper authentication (CWE-287), etc. Also consider children such as Insertion of Sensitive Information Into Sent Data (CWE-201), Observable Discrepancy (CWE-203), Insertion of Sensitive Information into Externally-Accessible File or Directory (CWE-538), or others.
Notes
Maintenance
As a result of mapping analysis in the 2020 Top 25 and more recent versions, this weakness is under review, since it is frequently misused in mapping to cover many problems that lead to loss of confidentiality. See Mapping Notes, Extended Description, and Alternate Terms.
CWE-472: External Control of Assumed-Immutable Web Parameter
Weakness ID: 472
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.
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Description
The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields.
Extended Description
If a web product does not properly protect assumed-immutable values from modification in hidden form fields, parameters, cookies, or URLs, this can lead to modification of critical data. Web applications often mistakenly make the assumption that data passed to the client in hidden fields or cookies is not susceptible to tampering. Improper validation of data that are user-controllable can lead to the application processing incorrect, and often malicious, input.
For example, custom cookies commonly store session data or persistent data across sessions. This kind of session data is normally involved in security related decisions on the server side, such as user authentication and access control. Thus, the cookies might contain sensitive data such as user credentials and privileges. This is a dangerous practice, as it can often lead to improper reliance on the value of the client-provided cookie by the server side application.
Alternate Terms
Assumed-Immutable Parameter Tampering
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
Technical Impact: Modify Application Data
Without appropriate protection mechanisms, the client can easily tamper with cookies and similar web data. Reliance on the cookies without detailed validation can lead to problems such as SQL injection. If you use cookie values for security related decisions on the server side, manipulating the cookies might lead to violations of security policies such as authentication bypassing, user impersonation and privilege escalation. In addition, storing sensitive data in the cookie without appropriate protection can also lead to disclosure of sensitive user data, especially data stored in persistent cookies.
Potential Mitigations
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: 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.
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.
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.
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.
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 "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.
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 "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.
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
OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.
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)
Demonstrative Examples
Example 1
In this example, a web application uses the value of a hidden form field (accountID) without having done any input validation because it was assumed to be immutable.
(bad code)
Example Language: Java
String accountID = request.getParameter("accountID"); User user = getUserFromID(Long.parseLong(accountID));
Example 2
Hidden fields should not be trusted as secure parameters.
An attacker can intercept and alter hidden fields in a post to the server as easily as user input fields. An attacker can simply parse the HTML for the substring:
(bad code)
Example Language: HTML
<input type="hidden"
or even just "hidden". Hidden field values displayed later in the session, such as on the following page, can open a site up to cross-site scripting attacks.
Modification of message number parameter allows attackers to read other people's messages.
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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.
Notes
Relationship
This is a primary weakness for many other weaknesses and functional consequences, including XSS, SQL injection, path disclosure, and file inclusion.
[REF-44] Michael Howard, David LeBlanc
and John Viega. "24 Deadly Sins of Software Security". "Sin 4: Use of Magic URLs, Predictable Cookies, and Hidden Form
Fields." Page 75. McGraw-Hill. 2010.
[REF-62] Mark Dowd, John McDonald
and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "Embedding State in HTML and URLs", Page 1032. 1st Edition. Addison Wesley. 2006.
CWE-209: Generation of Error Message Containing Sensitive Information
Weakness ID: 209
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.
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Description
The product generates an error message that includes sensitive information about its environment, users, or associated data.
Extended Description
The sensitive information may be valuable information on its own (such as a password), or it may be useful for launching other, more serious attacks. The error message may be created in different ways:
self-generated: the source code explicitly constructs the error message and delivers it
externally-generated: the external environment, such as a language interpreter, handles the error and constructs its own message, whose contents are not under direct control by the programmer
An attacker may use the contents of error messages to help launch another, more focused attack. For example, an attempt to exploit a path traversal weakness (CWE-22) might yield the full pathname of the installed application. In turn, this could be used to select the proper number of ".." sequences to navigate to the targeted file. An attack using SQL injection (CWE-89) might not initially succeed, but an error message could reveal the malformed query, which would expose query logic and possibly even passwords or other sensitive information used within the query.
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
Confidentiality
Technical Impact: Read Application Data
Often this will either reveal sensitive information which may be used for a later attack or private information stored in the server.
Potential Mitigations
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.
Phase: Implementation
Handle exceptions internally and do not display errors containing potentially sensitive information to a user.
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.
Phases: Implementation; Build and Compilation
Strategy: Compilation or Build Hardening
Debugging information should not make its way into a production release.
Phases: Implementation; Build and Compilation
Strategy: Environment Hardening
Debugging information should not make its way into a production release.
Phase: System Configuration
Where available, configure the environment to use less verbose error messages. For example, in PHP, disable the display_errors setting during configuration, or at runtime using the error_reporting() function.
Phase: System Configuration
Create default error pages or messages that do not leak any information.
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
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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 "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.
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 "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.
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
Architecture and Design
Implementation
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
System Configuration
Operation
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
PHP (Often Prevalent)
Java (Often Prevalent)
Class: Not Language-Specific (Undetermined Prevalence)
Likelihood Of Exploit
High
Demonstrative Examples
Example 1
In the following example, sensitive information might be printed depending on the exception that occurs.
(bad code)
Example Language: Java
try {
/.../
} catch (Exception e) {
System.out.println(e);
}
If an exception related to SQL is handled by the catch, then the output might contain sensitive information such as SQL query structure or private information. If this output is redirected to a web user, this may represent a security problem.
Example 2
This code tries to open a database connection, and prints any exceptions that occur.
(bad code)
Example Language: PHP
try {
openDbConnection();
} //print exception message that includes exception message and configuration file location catch (Exception $e) {
If an exception occurs, the printed message exposes the location of the configuration file the script is using. An attacker can use this information to target the configuration file (perhaps exploiting a Path Traversal weakness). If the file can be read, the attacker could gain credentials for accessing the database. The attacker may also be able to replace the file with a malicious one, causing the application to use an arbitrary database.
Example 3
The following code generates an error message that leaks the full pathname of the configuration file.
# avoid CWE-22, CWE-78, others. ExitError("Bad hacker!") if ($uname !~ /^\w+$/); $file = "$ConfigDir/$uname.txt"; if (! (-e $file)) {
ExitError("Error: $file does not exist");
} ...
If this code is running on a server, such as a web application, then the person making the request should not know what the full pathname of the configuration directory is. By submitting a username that does not produce a $file that exists, an attacker could get this pathname. It could then be used to exploit path traversal or symbolic link following problems that may exist elsewhere in the application.
Example 4
In the example below, the method getUserBankAccount retrieves a bank account object from a database using the supplied username and account number to query the database. If an SQLException is raised when querying the database, an error message is created and output to a log file.
(bad code)
Example Language: Java
public BankAccount getUserBankAccount(String username, String accountNumber) {
query = "SELECT * FROM accounts WHERE owner = " + username + " AND accountID = " + accountNumber; DatabaseManager dbManager = new DatabaseManager(); Connection conn = dbManager.getConnection(); Statement stmt = conn.createStatement(); ResultSet queryResult = stmt.executeQuery(query); userAccount = (BankAccount)queryResult.getObject(accountNumber);
}
} catch (SQLException ex) {
String logMessage = "Unable to retrieve account information from database,\nquery: " + query; Logger.getLogger(BankManager.class.getName()).log(Level.SEVERE, logMessage, ex);
} return userAccount;
}
The error message that is created includes information about the database query that may contain sensitive information about the database or query logic. In this case, the error message will expose the table name and column names used in the database. This data could be used to simplify other attacks, such as SQL injection (CWE-89) to directly access the database.
Composite: application running with high privileges (CWE-250) allows user to specify a restricted file to process, which generates a parsing error that leaks the contents of the file (CWE-209).
(where the weakness exists independent of other weaknesses)
Resultant
(where the weakness is typically related to the presence of some other weaknesses)
Detection Methods
Manual Analysis
This weakness generally requires domain-specific interpretation using manual analysis. However, the number of potential error conditions may be too large to cover completely within limited time constraints.
Effectiveness: High
Automated Analysis
Automated methods may be able to detect certain idioms automatically, such as exposed stack traces or pathnames, but violation of business rules or privacy requirements is not typically feasible.
Effectiveness: Moderate
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.
Error conditions may be triggered 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.
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
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.)
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
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).
(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
CLASP
Accidental leaking of sensitive information through error messages
OWASP Top Ten 2007
A6
CWE More Specific
Information Leakage and Improper Error Handling
OWASP Top Ten 2004
A7
CWE More Specific
Improper Error Handling
OWASP Top Ten 2004
A10
CWE More Specific
Insecure Configuration Management
The CERT Oracle Secure Coding Standard for Java (2011)
ERR01-J
Do not allow exceptions to expose sensitive information
[REF-175] Brian Chess and
Jacob West. "Secure Programming with Static Analysis". Section 9.2, Page 326. Addison-Wesley. 2007.
[REF-176] Michael Howard and
David LeBlanc. "Writing Secure Code". Chapter 16, "General Good Practices." Page 415. 1st Edition. Microsoft Press. 2001-11-13.
[REF-44] Michael Howard, David LeBlanc
and John Viega. "24 Deadly Sins of Software Security". "Sin 11: Failure to Handle Errors Correctly." Page 183. McGraw-Hill. 2010.
[REF-44] Michael Howard, David LeBlanc
and John Viega. "24 Deadly Sins of Software Security". "Sin 12: Information Leakage." Page 191. McGraw-Hill. 2010.
[REF-62] Mark Dowd, John McDonald
and Justin Schuh. "The Art of Software Security Assessment". Chapter 3, "Overly Verbose Error Messages", Page 75. 1st Edition. Addison Wesley. 2006.
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:
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.
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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."
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 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.
Potential Mitigations
Phase: Architecture and Design
Strategy: Libraries or Frameworks
Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
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
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)
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).
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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 "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.
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
Architecture and Design
Implementation
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
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)
Technologies
Class: ICS/OT (Often Prevalent)
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'))) {
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.
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.
Chat application skips validation when Central Authentication Service (CAS) is enabled, effectively removing the second factor from two-factor authentication
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.
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).
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)
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.
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.
chain: product generates predictable MD5 hashes using a constant value combined with username, allowing authentication bypass.
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:
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).
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).
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).
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).
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).
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).
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.
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:
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.
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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.
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
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.
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.
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
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
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.
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.
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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 "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.
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
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
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
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)
Technologies
Web Server (Often Prevalent)
Database Server (Often Prevalent)
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();
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.
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.
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
Chain: SNMP product does not properly parse a configuration option for which hosts are allowed to connect, allowing unauthorized IP addresses to connect.
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.
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
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.
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:
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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.
[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.
CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
Weakness ID: 98
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:
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.
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Description
The PHP application receives input from an upstream component, but it does not restrict or incorrectly restricts the input before its usage in "require," "include," or similar functions.
Extended Description
In certain versions and configurations of PHP, this can allow an attacker to specify a URL to a remote location from which the product will obtain the code to execute. In other cases in association with path traversal, the attacker can specify a local file that may contain executable statements that can be parsed by PHP.
Alternate Terms
Remote file include
RFI:
The Remote File Inclusion (RFI) acronym is often used by vulnerability researchers.
Local file inclusion:
This term is frequently used in cases in which remote download is disabled, or when the first part of the filename is not under the attacker's control, which forces use of relative path traversal (CWE-23) attack techniques to access files that may contain previously-injected PHP code, such as web access logs.
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 specify arbitrary code to be executed from a remote location. Alternatively, it may be possible to use normal program behavior to insert php code into files on the local machine which can then be included and force the code to execute since php ignores everything in the file except for the content between php specifiers.
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.
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.
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.
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: 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.
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: 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.
When validating filenames, use stringent lists 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.
Effectiveness: High
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.
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.
Many file inclusion problems occur because the programmer assumed that certain inputs could not be modified, especially for cookies and URL components.
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: Operation; Implementation
Strategy: Environment Hardening
Develop and run your code in the most recent versions of PHP available, preferably PHP 6 or later. Many of the highly risky features in earlier PHP interpreters have been removed, restricted, or disabled by default.
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.
Often, programmers do not protect direct access to files intended only to be included by core programs. These include files may assume that critical variables have already been initialized by the calling program. As a result, the use of register_globals combined with the ability to directly access the include file may allow attackers to conduct file inclusion attacks. This remains an extremely common pattern as of 2009.
Phase: Operation
Strategy: Environment Hardening
Set allow_url_fopen to false, which limits the ability to include files from remote locations.
Effectiveness: High
Note: Be aware that some versions of PHP will still accept ftp:// and other URI schemes. In addition, this setting does not protect the code from path traversal attacks (CWE-22), which are frequently successful against the same vulnerable code that allows remote file inclusion.
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
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
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
PHP (Often Prevalent)
Likelihood Of Exploit
High
Demonstrative Examples
Example 1
The following code, victim.php, attempts to include a function contained in a separate PHP page on the server. It builds the path to the file by using the supplied 'module_name' parameter and appending the string '/function.php' to it.
The problem with the above code is that the value of $dir is not restricted in any way, and a malicious user could manipulate the 'module_name' parameter to force inclusion of an unanticipated file. For example, an attacker could request the above PHP page (example.php) with a 'module_name' of "http://malicious.example.com" by using the following request string:
Upon receiving this request, the code would set 'module_name' to the value "http://malicious.example.com" and would attempt to include http://malicious.example.com/function.php, along with any malicious code it contains.
For the sake of this example, assume that the malicious version of function.php looks like the following:
(bad code)
system($_GET['cmd']);
An attacker could now go a step further in our example and provide a request string as follows:
The code will attempt to include the malicious function.php file from the remote site. In turn, this file executes the command specified in the 'cmd' parameter from the query string. The end result is an attempt by tvictim.php to execute the potentially malicious command, in this case:
(attack code)
/bin/ls -l
Note that the above PHP example can be mitigated by setting allow_url_fopen to false, although this will not fully protect the code. See potential mitigations.
PHP file inclusion issue, both remote and local; local include uses ".." and "%00" characters as a manipulation, but many remote file inclusion issues probably have this vector.
chain: library file sends a redirect if it is directly requested but continues to execute, allowing remote file inclusion and path traversal.
Detection Methods
Manual Analysis
Manual white-box analysis can be very effective for finding this issue, since there is typically a relatively small number of include or require statements in each program.
Effectiveness: High
Automated Static Analysis
The external control or influence of filenames can often be detected using automated static analysis that models data flow within the product.
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. If the program uses a customized input validation library, then some tools may allow the analyst to create custom signatures to detect usage of those routines.
Affected Resources
File or Directory
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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:
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.
Notes
Relationship
This is frequently a functional consequence of other weaknesses. It is usually multi-factor with other factors (e.g. MAID), although not all inclusion bugs involve assumed-immutable data. Direct request weaknesses frequently play a role.
Can overlap directory traversal in local inclusion problems.
CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Weakness ID: 22
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.
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Description
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.
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" to access unexpected files. This is referred to as absolute path traversal.
Alternate Terms
Directory traversal
Path traversal:
"Path traversal" is preferred over "directory traversal," but both terms are attack-focused.
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 protection mechanisms such as authentication, it has the potential to lock out product users.
Potential Mitigations
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.
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
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.
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
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.
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
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.
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.
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
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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.
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 "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.
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 "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.
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 "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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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)
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;
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);
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 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.
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 {
} // 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
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.
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.
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.
Large language model (LLM) management tool does not validate the format of a digest value (CWE-1287) from a private, untrusted model registry, enabling relative path traversal (CWE-23), a.k.a. Probllama
Chain: API for text generation using Large Language Models (LLMs) does not include the "\" Windows folder separator in its denylist (CWE-184) when attempting to prevent Local File Inclusion via path traversal (CWE-22), allowing deletion of arbitrary files on Windows systems.
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)
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 "../"
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.
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.
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
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"
Chain: library file sends a redirect if it is directly requested but continues to execute, allowing remote file inclusion and path traversal.
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:
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).
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).
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).
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).
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).
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).
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).
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).
(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.
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.
Other
In many programming languages, the injection of a null byte (the 0 or NUL) may allow an attacker to truncate a generated filename to apply to a wider range of files. 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.
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
[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.
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')
Weakness ID: 93
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:
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Description
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
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
Technical Impact: Modify Application Data
Potential Mitigations
Phase: Implementation
Avoid using CRLF as a special sequence.
Phase: Implementation
Appropriately filter or quote CRLF sequences in user-controlled input.
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
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.
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.
Base - a weakness
that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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 "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.
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 "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.
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
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
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)
Demonstrative Examples
Example 1
If user input data that eventually makes it to a log message isn't checked for CRLF characters, it may be possible for an attacker to forge entries in a log file.
(bad code)
Example Language: Java
logger.info("User's street address: " + request.getParameter("streetAddress"));
Chain: HTTP response splitting via CRLF in parameter related to URL.
Weakness Ordinalities
Ordinality
Description
Primary
(where the weakness exists independent of other weaknesses)
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(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.
CWE-95: Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')
Weakness ID: 95
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:
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.
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Description
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").
Extended Description
This may allow an attacker to execute arbitrary code, or at least modify what code can be executed.
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
Confidentiality
Technical Impact: Read Files or Directories; Read Application Data
The injected code could access restricted data / files.
Access Control
Technical Impact: Bypass Protection Mechanism
In some cases, injectable code controls authentication; this may lead to a remote vulnerability.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Injected code can access resources that the attacker is directly prevented from accessing.
Integrity Confidentiality Availability Other
Technical Impact: Execute Unauthorized Code or Commands
Code injection attacks can lead to loss of data integrity in nearly all cases as the control-plane data injected is always incidental to data recall or writing. Additionally, code injection can often result in the execution of arbitrary code.
Non-Repudiation
Technical Impact: Hide Activities
Often the actions performed by injected control code are unlogged.
Potential Mitigations
Phases: Architecture and Design; Implementation
If possible, refactor your code so that it does not need to use eval() at all.
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: 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
For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].
Effectiveness: Discouraged Common Practice
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.
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 "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.
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
REALIZATION: This weakness is caused during implementation of an architectural security tactic.
Implementation
This weakness is prevalent in handler/dispatch procedures that might want to invoke a large number of functions, or set a large number of variables.
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
Java (Undetermined Prevalence)
JavaScript (Undetermined Prevalence)
Python (Undetermined Prevalence)
Perl (Undetermined Prevalence)
PHP (Undetermined Prevalence)
Ruby (Undetermined Prevalence)
Class: Interpreted (Undetermined Prevalence)
Technologies
AI/ML (Undetermined Prevalence)
Likelihood Of Exploit
Medium
Demonstrative Examples
Example 1
edit-config.pl: This CGI script is used to modify settings in a configuration file.
(bad code)
Example Language: Perl
use CGI qw(:standard);
sub config_file_add_key {
my ($fname, $key, $arg) = @_; # code to add a field/key to a file goes here
}
sub config_file_set_key {
my ($fname, $key, $arg) = @_; # code to set key to a particular file goes here
}
sub config_file_delete_key {
my ($fname, $key, $arg) = @_; # code to delete key from a particular file goes here
}
sub handleConfigAction {
my ($fname, $action) = @_; my $key = param('key'); my $val = param('val'); # this is super-efficient code, especially if you have to invoke # any one of dozens of different functions!
my $code = "config_file_$action_key(\$fname, \$key, \$val);"; eval($code);
}
$configfile = "/home/cwe/config.txt"; print header; if (defined(param('action'))) {
handleConfigAction($configfile, param('action'));
} else {
print "No action specified!\n";
}
The script intends to take the 'action' parameter and invoke one of a variety of functions based on the value of that parameter - config_file_add_key(), config_file_set_key(), or config_file_delete_key(). It could set up a conditional to invoke each function separately, but eval() is a powerful way of doing the same thing in fewer lines of code, especially when a large number of functions or variables are involved. Unfortunately, in this case, the attacker can provide other values in the action parameter, such as:
(attack code)
add_key(",","); system("/bin/ls");
This would produce the following string in handleConfigAction():
(result)
config_file_add_key(",","); system("/bin/ls");
Any arbitrary Perl code could be added after the attacker has "closed off" the construction of the original function call, in order to prevent parsing errors from causing the malicious eval() to fail before the attacker's payload is activated. This particular manipulation would fail after the system() call, because the "_key(\$fname, \$key, \$val)" portion of the string would cause an error, but this is irrelevant to the attack because the payload has already been activated.
Example 2
This simple script asks a user to supply a list of numbers as input and adds them together.
(bad code)
Example Language: Python
def main():
sum = 0
numbers = eval(input("Enter a space-separated list of numbers: "))
for num in numbers:
sum = sum + num
print(f"Sum of {numbers} = {sum}")
main()
The eval() function can take the user-supplied list and convert it into a Python list object, therefore allowing the programmer to use list comprehension methods to work with the data. However, if code is supplied to the eval() function, it will execute that code. For example, a malicious user could supply the following string:
(attack code)
__import__('subprocess').getoutput('rm -r *')
This would delete all the files in the current directory. For this reason, it is not recommended to use eval() with untrusted input.
A way to accomplish this without the use of eval() is to apply an integer conversion on the input within a try/except block. If the user-supplied input is not numeric, this will raise a ValueError. By avoiding eval(), there is no opportunity for the input string to be executed as code.
(good code)
Example Language: Python
def main():
sum = 0
numbers = input("Enter a space-separated list of numbers: ").split(" ")
try:
for num in numbers:
sum = sum + int(num)
print(f"Sum of {numbers} = {sum}")
except ValueError:
print("Error: invalid input")
main()
An alternative, commonly-cited mitigation for this kind of weakness is to use the ast.literal_eval() function, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].
Chain: regex in EXIF processor code does not correctly determine where a string ends (CWE-625), enabling eval injection (CWE-95), as exploited in the wild per CISA KEV.
Chain: backslash followed by a newline can bypass a validation step (CWE-20), leading to eval injection (CWE-95), as exploited in the wild per CISA KEV.
chain: Resultant eval injection. An invalid value prevents initialization of variables, which can be modified by attacker and later injected into PHP eval statement.
Chain: Execution after redirect triggers eval injection.
Weakness Ordinalities
Ordinality
Description
Primary
(where the weakness exists independent of other weaknesses)
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
Category - a CWE entry that contains a set of other entries that share a common characteristic.
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).
(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:
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.
Notes
Other
Factors: special character errors can play a role in increasing the variety of code that can be injected, although some vulnerabilities do not require special characters at all, e.g. when a single function without arguments can be referenced and a terminator character is not necessary.
Taxonomy Mappings
Mapped Taxonomy Name
Node ID
Fit
Mapped Node Name
PLOVER
Direct Dynamic Code Evaluation ('Eval Injection')
OWASP Top Ten 2007
A3
CWE More Specific
Malicious File Execution
OWASP Top Ten 2004
A6
CWE More Specific
Injection Flaws
Software Fault Patterns
SFP24
Tainted input to command
SEI CERT Perl Coding Standard
IDS35-PL
Exact
Do not invoke the eval form with a string argument
[REF-62] Mark Dowd, John McDonald
and Justin Schuh. "The Art of Software Security Assessment". Chapter 18, "Inline Evaluation", Page 1095. 1st Edition. Addison Wesley. 2006.