CWE-831: Signal Handler Function Associated with Multiple Signals
Learn about CWE-831 (Signal Handler Function Associated with Multiple Signals), its security impact, exploitation methods, and prevention guidelines.
What is Signal Handler Function Associated with Multiple Signals?
• Overview: Signal Handler Function Associated with Multiple Signals (CWE-831) occurs when a single function is designated to handle more than one signal. This can lead to race conditions if the function modifies shared state or uses non-reentrant functions, making it vulnerable to attacks.
• Exploitation Methods:
- Attackers can exploit this by sending different signals to invoke the same handler function, potentially interrupting its execution while it’s still running.
- Common attack patterns include sending one signal to start the handler and another to interrupt it, leading to state corruption or unintended side effects.
• Security Impact:
- Direct consequences include denial of service or unexpected behavior due to state corruption.
- Potential cascading effects could involve data corruption or more severe system instability.
- Business impact might involve system downtime, reputational damage, or unauthorized access if the vulnerability is exploited for code execution.
• Prevention Guidelines:
- Use separate handler functions for different signals to avoid shared state issues.
- Avoid using global variables or non-reentrant functions inside signal handlers.
- Implement signal masking to block specific signals while the handler is executing.
- Consider using safer alternatives like event-driven programming or threads if applicable.
- Recommended tools and frameworks include static analysis tools that can identify improper signal handling patterns.
Technical Details
Likelihood of Exploit: Not specified
Affected Languages: Not specified
Affected Technologies: Not specified