Overview
The FreeBSD operating system does not adequately clear signal handlers subsequent to a process calling exec() on a setuid program. This vulnerability can allow a local attacker to execute arbitrary code as root.
Description
The unix fork() function's purpose is to create a new process from an existing process. The new process is called the child process, and the existing process is called the parent. When a process forks, it inherits the parent's signal handling settings. The unix exec() function's purpose is to replace the current process image with a new process image. After this has occured, the kernel should clear the signal handlers because they are no longer valid. Because the FreeBSD operating system does not adequately clear signal handlers subsequent to a process calling exec(), an attacker can execute arbitrary code as root. |
Impact
An local attacker may be able to execute arbitrary code as root. |
Solution
Apply a patch from your vendor or upgrade your operating system to FreeBSD 4.3-STABLE. |
Vendor Information
CVSS Metrics
| Group | Score | Vector |
|---|---|---|
| Base | ||
| Temporal | ||
| Environmental |
References
Acknowledgements
The CERT Coordination Center thanks Georgi Guninski for discovering this vulnerability and the FreeBSD project for providing a patch to address the vulnerability.
This document was written by Ian A. Finlay.
Other Information
| CVE IDs: | CVE-2001-1180 |
| Severity Metric: | 29.25 |
| Date Public: | 2001-07-10 |
| Date First Published: | 2001-09-14 |
| Date Last Updated: | 2002-12-12 18:39 UTC |
| Document Revision: | 30 |