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Description
The program defines a signal handler that calls a non-reentrant function.
Modes of Introduction:
– Architecture and Design
Likelihood of Exploit: Low
Related Weaknesses
CWE-828
CWE-663
CWE-123
Consequences
Integrity, Confidentiality, Availability: Execute Unauthorized Code or Commands
It may be possible to execute arbitrary code through the use of a write-what-where condition.
Integrity: Modify Memory, Modify Application Data
Signal race conditions often result in data corruption.
Potential Mitigations
Phase: Requirements
Description:
Require languages or libraries that provide reentrant functionality, or otherwise make it easier to avoid this weakness.
Phase: Architecture and Design
Description:
Design signal handlers to only set flags rather than perform complex functionality.
Phase: Implementation
Description:
Ensure that non-reentrant functions are not found in signal handlers.
Phase: Implementation
Effectiveness: Defense in Depth
Description:
Use sanity checks to reduce the timing window for exploitation of race conditions. This is only a partial solution, since many attacks might fail, but other attacks still might work within the narrower window, even accidentally.
CVE References
- CVE-2005-0893
- signal handler calls function that ultimately uses malloc()
- CVE-2004-2259
- SIGCHLD signal to FTP server can cause crash under heavy load while executing non-reentrant functions like malloc/free.
