CWE

Common Weakness Enumeration

A community-developed list of SW & HW weaknesses that can become vulnerabilities

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ID

CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Weakness ID: 120
Vulnerability Mapping: ALLOWEDThis CWE ID could be used to map to real-world vulnerabilities in limited situations requiring careful review (with careful review of mapping notes)
Abstraction: BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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+ Description
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.
+ Extended Description
A buffer overflow condition exists when a product attempts to put more data in a buffer than it can hold, or when it attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the product copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.
+ Alternate Terms
Classic Buffer Overflow:
This term was frequently used by vulnerability researchers during approximately 1995 to 2005 to differentiate buffer copies without length checks (which had been known about for decades) from other emerging weaknesses that still involved invalid accesses of buffers, as vulnerability researchers began to develop advanced exploitation techniques.
Unbounded Transfer
+ Common Consequences
Section HelpThis 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.
ScopeImpactLikelihood
Integrity
Confidentiality
Availability

Technical Impact: Modify Memory; Execute Unauthorized Code or Commands

Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of the product's implicit security policy. This can often be used to subvert any other security service.
Availability

Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)

Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the product into an infinite loop.
+ Potential Mitigations

Phase: Requirements

Strategy: Language Selection

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

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

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

Phase: Architecture and Design

Strategy: Libraries or Frameworks

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

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

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

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

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

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

Effectiveness: Defense in Depth

Note:

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

Phase: Implementation

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

  • Double check that your buffer is as large as you specify.
  • When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.
  • Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.
  • If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.

Phase: Implementation

Strategy: Input Validation

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

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

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

Phase: Architecture and Design

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

Phases: Operation; Build and Compilation

Strategy: Environment Hardening

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

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

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

Effectiveness: Defense in Depth

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

Phase: Operation

Strategy: Environment Hardening

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

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

Effectiveness: Defense in Depth

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

Phases: Build and Compilation; Operation

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

Phase: Implementation

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

Effectiveness: Moderate

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

Phase: Architecture and Design

Strategy: Enforcement by Conversion

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

Phases: Architecture and Design; Operation

Strategy: Environment Hardening

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

Phases: Architecture and Design; Operation

Strategy: Sandbox or Jail

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.
+ Relationships
Section HelpThis 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)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.119Improper Restriction of Operations within the Bounds of a Memory Buffer
ParentOfVariantVariant - 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.785Use of Path Manipulation Function without Maximum-sized Buffer
CanFollowBaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.170Improper Null Termination
CanFollowVariantVariant - 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.231Improper Handling of Extra Values
CanFollowVariantVariant - 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.416Use After Free
CanFollowVariantVariant - 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.456Missing Initialization of a Variable
CanPrecedeBaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.123Write-what-where Condition
Section HelpThis 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)
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1218Memory Buffer Errors
Section HelpThis 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)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.119Improper Restriction of Operations within the Bounds of a Memory Buffer
Section HelpThis 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)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.119Improper Restriction of Operations within the Bounds of a Memory Buffer
Section HelpThis 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)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.119Improper Restriction of Operations within the Bounds of a Memory Buffer
Section HelpThis 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 "Seven Pernicious Kingdoms" (CWE-700)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.20Improper Input Validation
+ Modes Of Introduction
Section HelpThe 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.
PhaseNote
Implementation
+ Applicable Platforms
Section HelpThis 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

C (Undetermined Prevalence)

C++ (Undetermined Prevalence)

Class: Assembly (Undetermined Prevalence)

+ Likelihood Of Exploit
High
+ Demonstrative Examples

Example 1

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

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

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


Example 2

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

(bad code)
Example Language:
void manipulate_string(char * string){
char buf[24];
strcpy(buf, string);
...
}

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


Example 3

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

(bad code)
Example Language:
char buf[24];
printf("Please enter your name and press <Enter>\n");
gets(buf);
...
}

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


Example 4

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

(bad code)
Example Language:
...
struct hostent *clienthp;
char hostname[MAX_LEN];

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

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

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

if (clientsocket >= 0) {
clienthp = gethostbyaddr((char*) &clientaddr.sin_addr.s_addr, sizeof(clientaddr.sin_addr.s_addr), AF_INET);
strcpy(hostname, clienthp->h_name);
logOutput("Accepted client connection from host ", hostname);

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

...

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


+ Observed Examples
ReferenceDescription
buffer overflow using command with long argument
buffer overflow in local program using long environment variable
buffer overflow in comment characters, when product increments a counter for a ">" but does not decrement for "<"
By replacing a valid cookie value with an extremely long string of characters, an attacker may overflow the application's buffers.
By replacing a valid cookie value with an extremely long string of characters, an attacker may overflow the application's buffers.
+ Weakness Ordinalities
OrdinalityDescription
Resultant
(where the weakness is typically related to the presence of some other weaknesses)
Primary
(where the weakness exists independent of other weaknesses)
+ Detection Methods

Automated Static Analysis

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

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

Effectiveness: High

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

Automated Dynamic Analysis

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

Manual Analysis

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

Automated Static Analysis - Binary or Bytecode

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

Highly cost effective:
  • Bytecode Weakness Analysis - including disassembler + source code weakness analysis
  • Binary Weakness Analysis - including disassembler + source code weakness analysis

Effectiveness: High

Manual Static Analysis - Binary or Bytecode

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

Cost effective for partial coverage:
  • Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

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

Cost effective for partial coverage:
  • Web Application Scanner
  • Web Services Scanner
  • Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

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

Cost effective for partial coverage:
  • Fuzz Tester
  • Framework-based Fuzzer

Effectiveness: SOAR Partial

Manual Static Analysis - Source Code

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

Cost effective for partial coverage:
  • Focused Manual Spotcheck - Focused manual analysis of source
  • Manual Source Code Review (not inspections)

Effectiveness: SOAR Partial

Automated Static Analysis - Source Code

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

Highly cost effective:
  • Source code Weakness Analyzer
  • Context-configured Source Code Weakness Analyzer

Effectiveness: High

Architecture or Design Review

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

Highly cost effective:
  • Formal Methods / Correct-By-Construction
Cost effective for partial coverage:
  • Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness: High

+ Functional Areas
  • Memory Management
+ Affected Resources
  • Memory
+ Memberships
Section HelpThis 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.
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.722OWASP Top Ten 2004 Category A1 - Unvalidated Input
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.726OWASP Top Ten 2004 Category A5 - Buffer Overflows
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.741CERT C Secure Coding Standard (2008) Chapter 8 - Characters and Strings (STR)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.8022010 Top 25 - Risky Resource Management
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.8652011 Top 25 - Risky Resource Management
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.875CERT C++ Secure Coding Section 07 - Characters and Strings (STR)
MemberOfViewView - 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).884CWE Cross-section
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.970SFP Secondary Cluster: Faulty Buffer Access
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1129CISQ Quality Measures (2016) - Reliability
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1131CISQ Quality Measures (2016) - Security
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1161SEI CERT C Coding Standard - Guidelines 07. Characters and Strings (STR)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1399Comprehensive Categorization: Memory Safety
+ Vulnerability Mapping Notes

Usage: ALLOWED-WITH-REVIEW

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

Reason: Frequent Misuse

Rationale:

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

Comments:

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

Relationship

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

Terminology

Many issues that are now called "buffer overflows" are substantively different than the "classic" overflow, including entirely different bug types that rely on overflow exploit techniques, such as integer signedness errors, integer overflows, and format string bugs. This imprecise terminology can make it difficult to determine which variant is being reported.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERUnbounded Transfer ('classic overflow')
7 Pernicious KingdomsBuffer Overflow
CLASPBuffer overflow
OWASP Top Ten 2004A1CWE More SpecificUnvalidated Input
OWASP Top Ten 2004A5CWE More SpecificBuffer Overflows
CERT C Secure CodingSTR31-CExactGuarantee that storage for strings has sufficient space for character data and the null terminator
WASC7Buffer Overflow
Software Fault PatternsSFP8Faulty Buffer Access
OMG ASCSMASCSM-CWE-120
OMG ASCRMASCRM-CWE-120
+ References
[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 5, "Public Enemy #1: The Buffer Overrun" Page 127. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.
[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 5: Buffer Overruns." Page 89. McGraw-Hill. 2010.
[REF-56] Microsoft. "Using the Strsafe.h Functions". <https://learn.microsoft.com/en-us/windows/win32/menurc/strsafe-ovw?redirectedfrom=MSDN>. URL validated: 2023-04-07.
[REF-57] Matt Messier and John Viega. "Safe C String Library v1.0.3". <http://www.gnu-darwin.org/www001/ports-1.5a-CURRENT/devel/safestr/work/safestr-1.0.3/doc/safestr.html>. URL validated: 2023-04-07.
[REF-58] Michael Howard. "Address Space Layout Randomization in Windows Vista". <https://learn.microsoft.com/en-us/archive/blogs/michael_howard/address-space-layout-randomization-in-windows-vista>. URL validated: 2023-04-07.
[REF-59] Arjan van de Ven. "Limiting buffer overflows with ExecShield". <https://archive.is/saAFo>. URL validated: 2023-04-07.
[REF-60] "PaX". <https://en.wikipedia.org/wiki/Executable_space_protection#PaX>. URL validated: 2023-04-07.
[REF-74] Jason Lam. "Top 25 Series - Rank 3 - Classic Buffer Overflow". SANS Software Security Institute. 2010-03-02. <http://software-security.sans.org/blog/2010/03/02/top-25-series-rank-3-classic-buffer-overflow/>.
[REF-61] Microsoft. "Understanding DEP as a mitigation technology part 1". <https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/>. URL validated: 2023-04-07.
[REF-76] Sean Barnum and Michael Gegick. "Least Privilege". 2005-09-14. <https://web.archive.org/web/20211209014121/https://www.cisa.gov/uscert/bsi/articles/knowledge/principles/least-privilege>. URL validated: 2023-04-07.
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 3, "Nonexecutable Stack", Page 76. 1st Edition. Addison Wesley. 2006.
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 5, "Protection Mechanisms", Page 189. 1st Edition. Addison Wesley. 2006.
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 8, "C String Handling", Page 388. 1st Edition. Addison Wesley. 2006.
[REF-64] Grant Murphy. "Position Independent Executables (PIE)". Red Hat. 2012-11-28. <https://www.redhat.com/en/blog/position-independent-executables-pie>. URL validated: 2023-04-07.
[REF-961] Object Management Group (OMG). "Automated Source Code Reliability Measure (ASCRM)". ASCRM-CWE-120. 2016-01. <http://www.omg.org/spec/ASCRM/1.0/>.
[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-120. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.
[REF-1332] John Richard Moser. "Prelink and address space randomization". 2006-07-05. <https://lwn.net/Articles/190139/>. URL validated: 2023-04-26.
[REF-1333] Dmitry Evtyushkin, Dmitry Ponomarev, Nael Abu-Ghazaleh. "Jump Over ASLR: Attacking Branch Predictors to Bypass ASLR". 2016. <http://www.cs.ucr.edu/~nael/pubs/micro16.pdf>. URL validated: 2023-04-26.
[REF-1334] D3FEND. "Stack Frame Canary Validation (D3-SFCV)". 2023. <https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/>. URL validated: 2023-04-26.
[REF-1335] D3FEND. "Segment Address Offset Randomization (D3-SAOR)". 2023. <https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/>. URL validated: 2023-04-26.
[REF-1336] D3FEND. "Process Segment Execution Prevention (D3-PSEP)". 2023. <https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/>. URL validated: 2023-04-26.
[REF-1337] Alexander Sotirov and Mark Dowd. "Bypassing Browser Memory Protections: Setting back browser security by 10 years". Memory information leaks. 2008. <https://www.blackhat.com/presentations/bh-usa-08/Sotirov_Dowd/bh08-sotirov-dowd.pdf>. URL validated: 2023-04-26.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2006-07-19
(CWE Draft 3, 2006-07-19)
PLOVER
+ Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-08-01KDM Analytics
added/updated white box definitions
2008-08-15Veracode
Suggested OWASP Top Ten 2004 mapping
2008-09-08CWE Content TeamMITRE
updated Alternate_Terms, Applicable_Platforms, Common_Consequences, Relationships, Observed_Example, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-10-10CWE Content TeamMITRE
Changed name and description to more clearly emphasize the "classic" nature of the overflow.
2008-10-14CWE Content TeamMITRE
updated Alternate_Terms, Description, Name, Other_Notes, Terminology_Notes
2008-11-24CWE Content TeamMITRE
updated Other_Notes, Relationships, Taxonomy_Mappings
2009-01-12CWE Content TeamMITRE
updated Common_Consequences, Other_Notes, Potential_Mitigations, References, Relationship_Notes, Relationships
2009-07-27CWE Content TeamMITRE
updated Other_Notes, Potential_Mitigations, Relationships
2009-10-29CWE Content TeamMITRE
updated Common_Consequences, Relationships
2010-02-16CWE Content TeamMITRE
updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Potential_Mitigations, References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings, Time_of_Introduction, Type
2010-04-05CWE Content TeamMITRE
updated Demonstrative_Examples, Related_Attack_Patterns
2010-06-21CWE Content TeamMITRE
updated Common_Consequences, Potential_Mitigations, References
2010-09-27CWE Content TeamMITRE
updated Potential_Mitigations
2010-12-13CWE Content TeamMITRE
updated Potential_Mitigations
2011-03-29CWE Content TeamMITRE
updated Demonstrative_Examples, Description
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Relationships
2011-09-13CWE Content TeamMITRE
updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
2012-05-11CWE Content TeamMITRE
updated References, Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2014-02-18CWE Content TeamMITRE
updated Potential_Mitigations, References
2014-07-30CWE Content TeamMITRE
updated Detection_Factors, Relationships, Taxonomy_Mappings
2017-11-08CWE Content TeamMITRE
updated Applicable_Platforms, Causal_Nature, Demonstrative_Examples, Likelihood_of_Exploit, References, Relationships, Taxonomy_Mappings, White_Box_Definitions
2018-03-27CWE Content TeamMITRE
updated References
2019-01-03CWE Content TeamMITRE
updated References, Relationships, Taxonomy_Mappings
2019-06-20CWE Content TeamMITRE
updated Relationships
2020-02-24CWE Content TeamMITRE
updated Potential_Mitigations, Relationships
2020-06-25CWE Content TeamMITRE
updated Common_Consequences, Potential_Mitigations
2020-08-20CWE Content TeamMITRE
updated Alternate_Terms, Relationships
2020-12-10CWE Content TeamMITRE
updated Demonstrative_Examples, Relationships
2021-03-15CWE Content TeamMITRE
updated Demonstrative_Examples
2021-07-20CWE Content TeamMITRE
updated Potential_Mitigations
2022-10-13CWE Content TeamMITRE
updated References
2023-01-31CWE Content TeamMITRE
updated Common_Consequences, Description
2023-04-27CWE Content TeamMITRE
updated Potential_Mitigations, References, Relationships
2023-06-29CWE Content TeamMITRE
updated Mapping_Notes
+ Previous Entry Names
Change DatePrevious Entry Name
2008-10-14Unbounded Transfer ('Classic Buffer Overflow')
Page Last Updated: July 16, 2024