CWE-119
Alerte pour un CWE
Improper Restriction of Operations within the Bounds of a Memory Buffer
Extended Description
Certain languages allow direct addressing of memory locations and do not automatically ensure that these locations are valid for the memory buffer that is being referenced. This can cause read or write operations to be performed on memory locations that may be associated with other variables, data structures, or internal program data.
As a result, an attacker may be able to execute arbitrary code, alter the intended control flow, read sensitive information, or cause the system to crash.
Informations
Modes Of Introduction
ImplementationApplicable Platforms
Language
Name: C (Often)Name: C++ (Often)
Class: Assembly (Undetermined)
Common Consequences
| Scope | Impact | Likelihood |
|---|---|---|
| Integrity Confidentiality Availability | Execute Unauthorized Code or Commands, Modify Memory Note: If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can redirect a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator. | |
| Availability Confidentiality | Read Memory, DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory) Note: Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop. | |
| Confidentiality | Read Memory Note: In the case of an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffers position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences. |
Observed Examples
| Reference | Description |
|---|---|
| Incorrect URI normalization in application traffic product leads to buffer overflow, as exploited in the wild per CISA KEV. | |
| Buffer overflow in Wi-Fi router web interface, as exploited in the wild per CISA KEV. | |
| Classic stack-based buffer overflow in media player using a long entry in a playlist | |
| Heap-based buffer overflow in media player using a long entry in a playlist | |
| large precision value in a format string triggers overflow | |
| negative offset value leads to out-of-bounds read | |
| malformed inputs cause accesses of uninitialized or previously-deleted objects, leading to memory corruption | |
| chain: lack of synchronization leads to memory corruption | |
| Chain: machine-learning product can have a heap-based buffer overflow (CWE-122) when some integer-oriented bounds are calculated by using ceiling() and floor() on floating point values (CWE-1339) | |
| attacker-controlled array index leads to code execution | |
| chain: -1 value from a function call was intended to indicate an error, but is used as an array index instead. | |
| chain: incorrect calculations lead to incorrect pointer dereference and memory corruption | |
| product accepts crafted messages that lead to a dereference of an arbitrary pointer | |
| chain: malformed input causes dereference of uninitialized memory | |
| OS kernel trusts userland-supplied length value, allowing reading of sensitive information | |
| Chain: integer overflow in securely-coded mail program leads to buffer overflow. In 2005, this was regarded as unrealistic to exploit, but in 2020, it was rediscovered to be easier to exploit due to evolutions of the technology. | |
| buffer overflow involving a regular expression with a large number of captures | |
| chain: unchecked message size metadata allows integer overflow (CWE-190) leading to buffer overflow (CWE-119). |
Potential Mitigations
Phases : RequirementsUse 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.
Phases : Architecture and Design
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.
Phases : Operation // Build and Compilation
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.
Phases : Implementation
Consider adhering to the following rules when allocating and managing an application's memory:
- Double check that the buffer is as large as specified.
- When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.
- Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.
- If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.
Phases : Operation // Build and Compilation
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].
Phases : Operation
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].
Phases : Implementation
Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.
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
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.Automated Static Analysis - Binary or Bytecode
According to SOAR, the following detection techniques may be useful:
- Binary / Bytecode Quality Analysis
- Bytecode Weakness Analysis - including disassembler + source code weakness analysis
- Binary Weakness Analysis - including disassembler + source code weakness analysis
Effectiveness : SOAR Partial
Manual Static Analysis - Binary or Bytecode
According to SOAR, the following detection techniques may be useful:
- 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:
- 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:
- Fuzz Tester
- Framework-based Fuzzer
Effectiveness : SOAR Partial
Manual Static Analysis - Source Code
According to SOAR, the following detection techniques may be useful:
- 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:
- Source code Weakness Analyzer
- Context-configured Source Code Weakness Analyzer
- Source Code Quality Analyzer
Effectiveness : High
Architecture or Design Review
According to SOAR, the following detection techniques may be useful:
- Formal Methods / Correct-By-Construction
- Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)
Effectiveness : High
Vulnerability Mapping Notes
Rationale : CWE-119 is commonly misused in low-information vulnerability reports when lower-level CWEs could be used instead, or when more details about the vulnerability are available.Comments : Look at CWE-119's children and consider mapping to CWEs such as CWE-787: Out-of-bounds Write, CWE-125: Out-of-bounds Read, or others.
Related Attack Patterns
| CAPEC-ID | Attack Pattern Name |
|---|---|
| CAPEC-10 | Buffer Overflow via Environment Variables This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the adversary finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables. |
| CAPEC-100 | Overflow Buffers Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an adversary. As a consequence, an adversary is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the adversaries' choice. |
| CAPEC-123 | Buffer Manipulation An adversary manipulates an application's interaction with a buffer in an attempt to read or modify data they shouldn't have access to. Buffer attacks are distinguished in that it is the buffer space itself that is the target of the attack rather than any code responsible for interpreting the content of the buffer. In virtually all buffer attacks the content that is placed in the buffer is immaterial. Instead, most buffer attacks involve retrieving or providing more input than can be stored in the allocated buffer, resulting in the reading or overwriting of other unintended program memory. |
| CAPEC-14 | Client-side Injection-induced Buffer Overflow This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service. This hostile service is created to deliver the correct content to the client software. For example, if the client-side application is a browser, the service will host a webpage that the browser loads. |
| CAPEC-24 | Filter Failure through Buffer Overflow In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered). |
| CAPEC-42 | MIME Conversion An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back. |
| CAPEC-44 | Overflow Binary Resource File An attack of this type exploits a buffer overflow vulnerability in the handling of binary resources. Binary resources may include music files like MP3, image files like JPEG files, and any other binary file. These attacks may pass unnoticed to the client machine through normal usage of files, such as a browser loading a seemingly innocent JPEG file. This can allow the adversary access to the execution stack and execute arbitrary code in the target process. |
| CAPEC-45 | Buffer Overflow via Symbolic Links This type of attack leverages the use of symbolic links to cause buffer overflows. An adversary can try to create or manipulate a symbolic link file such that its contents result in out of bounds data. When the target software processes the symbolic link file, it could potentially overflow internal buffers with insufficient bounds checking. |
| CAPEC-46 | Overflow Variables and Tags This type of attack leverages the use of tags or variables from a formatted configuration data to cause buffer overflow. The adversary crafts a malicious HTML page or configuration file that includes oversized strings, thus causing an overflow. |
| CAPEC-47 | Buffer Overflow via Parameter Expansion In this attack, the target software is given input that the adversary knows will be modified and expanded in size during processing. This attack relies on the target software failing to anticipate that the expanded data may exceed some internal limit, thereby creating a buffer overflow. |
| CAPEC-8 | Buffer Overflow in an API Call This attack targets libraries or shared code modules which are vulnerable to buffer overflow attacks. An adversary who has knowledge of known vulnerable libraries or shared code can easily target software that makes use of these libraries. All clients that make use of the code library thus become vulnerable by association. This has a very broad effect on security across a system, usually affecting more than one software process. |
| CAPEC-9 | Buffer Overflow in Local Command-Line Utilities This attack targets command-line utilities available in a number of shells. An adversary can leverage a vulnerability found in a command-line utility to escalate privilege to root. |
Notes
It is possible in any programming languages without memory management support to attempt an operation outside of the bounds of a memory buffer, but the consequences will vary widely depending on the language, platform, and chip architecture.
References
REF-1029
Smashing The Stack For Fun And ProfitAleph One.
http://phrack.org/issues/49/14.html
REF-7
Writing Secure CodeMichael Howard, David LeBlanc.
https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223
REF-56
Using the Strsafe.h FunctionsMicrosoft.
https://learn.microsoft.com/en-us/windows/win32/menurc/strsafe-ovw?redirectedfrom=MSDN
REF-57
Safe C String Library v1.0.3Matt Messier, John Viega.
http://www.gnu-darwin.org/www001/ports-1.5a-CURRENT/devel/safestr/work/safestr-1.0.3/doc/safestr.html
REF-58
Address Space Layout Randomization in Windows VistaMichael Howard.
https://learn.microsoft.com/en-us/archive/blogs/michael_howard/address-space-layout-randomization-in-windows-vista
REF-59
Limiting buffer overflows with ExecShieldArjan van de Ven.
https://archive.is/saAFo
REF-60
PaXhttps://en.wikipedia.org/wiki/Executable_space_protection#PaX
REF-61
Understanding DEP as a mitigation technology part 1Microsoft.
https://msrc.microsoft.com/blog/2009/06/understanding-dep-as-a-mitigation-technology-part-1/
REF-62
The Art of Software Security AssessmentMark Dowd, John McDonald, Justin Schuh.
REF-64
Position Independent Executables (PIE)Grant Murphy.
https://www.redhat.com/en/blog/position-independent-executables-pie
REF-1332
Prelink and address space randomizationJohn Richard Moser.
https://lwn.net/Articles/190139/
REF-1333
Jump Over ASLR: Attacking Branch Predictors to Bypass ASLRDmitry Evtyushkin, Dmitry Ponomarev, Nael Abu-Ghazaleh.
http://www.cs.ucr.edu/~nael/pubs/micro16.pdf
REF-1334
Stack Frame Canary Validation (D3-SFCV)D3FEND.
https://d3fend.mitre.org/technique/d3f:StackFrameCanaryValidation/
REF-1335
Segment Address Offset Randomization (D3-SAOR)D3FEND.
https://d3fend.mitre.org/technique/d3f:SegmentAddressOffsetRandomization/
REF-1336
Process Segment Execution Prevention (D3-PSEP)D3FEND.
https://d3fend.mitre.org/technique/d3f:ProcessSegmentExecutionPrevention/
REF-1337
Bypassing Browser Memory Protections: Setting back browser security by 10 yearsAlexander Sotirov and Mark Dowd.
https://www.blackhat.com/presentations/bh-usa-08/Sotirov_Dowd/bh08-sotirov-dowd.pdf
Submission
| Name | Organization | Date | Date Release | Version |
|---|---|---|---|---|
| PLOVER | Draft 3 |
Modifications
| Name | Organization | Date | Comment |
|---|---|---|---|
| Eric Dalci | Cigital | updated Time_of_Introduction | |
| Veracode | Suggested OWASP Top Ten 2004 mapping | ||
| CWE Content Team | MITRE | updated Description, Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Likelihood_of_Exploit, Name, Potential_Mitigations, References, Relationships | |
| CWE Content Team | MITRE | updated Potential_Mitigations | |
| CWE Content Team | MITRE | updated Demonstrative_Examples | |
| CWE Content Team | MITRE | updated Observed_Examples | |
| CWE Content Team | MITRE | updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Relationships, Time_of_Introduction | |
| CWE Content Team | MITRE | updated Common_Consequences, Demonstrative_Examples, Detection_Factors, Observed_Examples | |
| CWE Content Team | MITRE | updated Alternate_Terms, Applicable_Platforms, Demonstrative_Examples, Detection_Factors, Potential_Mitigations, References, Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Potential_Mitigations | |
| CWE Content Team | MITRE | updated Potential_Mitigations, Relationships | |
| CWE Content Team | MITRE | updated Name | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Common_Consequences, Relationships | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Demonstrative_Examples, Potential_Mitigations, References, Relationships | |
| CWE Content Team | MITRE | updated Potential_Mitigations | |
| CWE Content Team | MITRE | updated Demonstrative_Examples | |
| CWE Content Team | MITRE | updated Potential_Mitigations, References | |
| CWE Content Team | MITRE | updated Detection_Factors, Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Observed_Examples, References, Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated References | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Related_Attack_Patterns, Relationships | |
| CWE Content Team | MITRE | updated References, Relationships | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings, Time_of_Introduction | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Alternate_Terms, Relationships | |
| CWE Content Team | MITRE | updated Alternate_Terms, Observed_Examples, Relationships | |
| CWE Content Team | MITRE | updated Demonstrative_Examples, Observed_Examples, Potential_Mitigations, Relationships | |
| CWE Content Team | MITRE | updated Observed_Examples, Relationships | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Alternate_Terms, Description | |
| CWE Content Team | MITRE | updated Potential_Mitigations, References, Relationships, Time_of_Introduction | |
| CWE Content Team | MITRE | updated Mapping_Notes, Relationships |
