According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Bytecode Weakness Analysis - including disassembler + source code weakness analysis Binary Weakness Analysis - including disassembler + source code weakness analysis ``` Cost effective for partial coverage: ``` Binary / Bytecode Quality Analysis Binary / Bytecode simple extractor - strings, ELF readers, etc.
CWE-676 Base Draft
Use of Potentially Dangerous Function
This vulnerability occurs when code calls a function that can be dangerous if misused, but can also be used safely with proper precautions. The risk lies not in the function itself, but in how it's…
Definition
What is CWE-676?
This vulnerability occurs when code calls a function that can be dangerous if misused, but can also be used safely with proper precautions. The risk lies not in the function itself, but in how it's implemented.
Many programming languages and libraries include powerful, low-level functions that offer performance benefits or direct system access. Functions like `strcpy()`, `eval()`, or `system()` are common examples. While they are legitimate tools, they become security risks when developers use them without validating input, managing memory, or understanding their side effects. The core issue is assuming these functions are safe by default, rather than treating them as operations that require explicit safeguards.
To mitigate this, developers should first seek safer, modern alternatives provided by the language or framework, such as bounded string copy functions or secure APIs. When a dangerous function must be used, it is critical to implement strict input validation, output encoding, and context-aware sanitization around it. Security is maintained by wrapping these functions with robust checks and limits, never trusting uncontrolled data, and conducting regular code reviews focused on these specific high-risk calls.
Real-world impact
Real-world CVEs caused by CWE-676
-
Library has multiple buffer overflows using sprintf() and strcpy()
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Buffer overflow using strcat()
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Buffer overflow using strcpy()
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Buffer overflow using strcpy()
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Vulnerable use of strcpy() changed to use safer strlcpy()
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Buffer overflow using strcpy()
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable C
The following code attempts to create a local copy of a buffer to perform some manipulations to the data.
void manipulate_string(char * string){
char buf[24];
strcpy(buf, string);
...
} Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-676
- Build and Compilation / Implementation Identify a list of prohibited API functions and prohibit developers from using these functions, providing safer alternatives. In some cases, automatic code analysis tools or the compiler can be instructed to spot use of prohibited functions, such as the "banned.h" include file from Microsoft's SDL. [REF-554] [REF-7]
Detection signals
How to detect CWE-676
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Debugger ``` Cost effective for partial coverage: ``` Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Manual Source Code Review (not inspections) ``` Cost effective for partial coverage: ``` Focused Manual Spotcheck - Focused manual analysis of source
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Source code Weakness Analyzer Context-configured Source Code Weakness Analyzer ``` Cost effective for partial coverage: ``` Warning Flags Source Code Quality Analyzer
According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Origin Analysis
CWE-676
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Frequently asked questions What is CWE-676?
How serious is CWE-676?
What languages or platforms are affected by CWE-676?
How can I prevent CWE-676?
How does Plexicus detect and fix CWE-676?
Where can I learn more about CWE-676?
Frequently asked questions
What is CWE-676?
This vulnerability occurs when code calls a function that can be dangerous if misused, but can also be used safely with proper precautions. The risk lies not in the function itself, but in how it's implemented.
How serious is CWE-676?
MITRE rates the likelihood of exploit as High — this weakness is actively exploited in the wild and should be prioritized for remediation.
What languages or platforms are affected by CWE-676?
MITRE lists the following affected platforms: C, C++.
How can I prevent CWE-676?
Identify a list of prohibited API functions and prohibit developers from using these functions, providing safer alternatives. In some cases, automatic code analysis tools or the compiler can be instructed to spot use of prohibited functions, such as the "banned.h" include file from Microsoft's SDL. [REF-554] [REF-7]
How does Plexicus detect and fix CWE-676?
Plexicus's SAST engine matches the data-flow signature for CWE-676 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-676?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/676.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-676
CWE-1177 Parent
Use of Prohibited Code
This vulnerability occurs when software incorporates a function, library, or third-party component that has been explicitly banned by the…
CWE-242 Sibling
Use of Inherently Dangerous Function
This vulnerability occurs when code uses functions that are inherently unsafe and cannot be reliably secured, posing a direct risk to…
CWE-785 Child
Use of Path Manipulation Function without Maximum-sized Buffer
This vulnerability occurs when a program uses a path manipulation function but supplies an output buffer that is too small to hold the…
Resources
Further reading
- MITRE — official CWE-676 https://cwe.mitre.org/data/definitions/676.html
- Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf
- Security Development Lifecycle (SDL) Banned Function Calls https://learn.microsoft.com/en-us/previous-versions/bb288454(v=msdn.10)?redirectedfrom=MSDN
- Writing Secure Code https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223
- State-of-the-Art Resources (SOAR) for Software Vulnerability Detection, Test, and Evaluation https://www.ida.org/-/media/feature/publications/s/st/stateoftheart-resources-soar-for-software-vulnerability-detection-test-and-evaluation/p-5061.ashx
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