CWE-828: Signal Handler with Functionality that is not Asynchronous-Safe
Learn about CWE-828 (Signal Handler with Functionality that is not Asynchronous-Safe), its security impact, exploitation methods, and prevention guidelines.
What is Signal Handler with Functionality that is not Asynchronous-Safe?
• Overview: Signal handlers should only contain code that is safe to execute at any point during the program's execution. This vulnerability occurs when a signal handler includes functionality that could be interrupted, leading to a corrupted or unexpected system state. This often involves using non-reentrant functions or shared resources that aren't protected against concurrent access.
• Exploitation Methods:
- Attackers can exploit this vulnerability by sending signals that trigger the handler at inappropriate times, leading to race conditions or corrupted data.
- Common attack patterns include sending multiple signals to a process to cause the handler to execute unexpectedly or repeatedly.
• Security Impact:
- Direct consequences of successful exploitation include denial of service or unexpected program behavior.
- Potential cascading effects include data corruption or security breaches when state variables are left in an inconsistent state.
- Business impact could involve system downtime, data loss, or unauthorized code execution, leading to financial loss or reputational damage.
• Prevention Guidelines:
- Specific code-level fixes include using only asynchronous-safe functions within signal handlers and avoiding global or static variables that aren't protected.
- Security best practices involve designing signal handlers that are minimal and strictly adhere to asynchronous-safety requirements.
- Recommended tools and frameworks include static analysis tools that can identify non-reentrant functions used in signal handlers and development environments that provide safer alternatives for signal handling.
Technical Details
Likelihood of Exploit: Not specified
Affected Languages: Not specified
Affected Technologies: Not specified