FreeBSD rfork(RFPROC|RFSIGSHARE) signal handlers allows local root compromise
| bsd-rfork-signal-handlers (6829) |  High Risk |
Description:
FreeBSD is vulnerable to a local root compromise, caused by a vulnerability in rfork(RFPROC|RFSIGSHARE). The rfork(RFPROC|RFSIGSHARE) fails to prevent signal handlers from being shared in other processes. This could allow a local attacker to inject signal handlers into a process to execute arbitrary code on the system with root privileges.
Platforms Affected:
- FreeBSD, FreeBSD 4.0
- FreeBSD, FreeBSD 4.1
- FreeBSD, FreeBSD 4.2
- FreeBSD, FreeBSD 4.3
Remedy:
No remedy available as of July 4, 2009.
Consequences:
Gain Access
References:
- CIAC Information Bulletin L-111, FreeBSD Signal Handling Flaw at http://www.ciac.org/ciac/bulletins/l-111.shtml.
- FreeBSD Security Advisory FreeBSD-SA-01:42, signal handling during exec may allow local root compromise at ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-01:42.signal.v1.1.asc.
- Georgi Guninski Security Advisory #48, FreeBSD 4.3 local root, yet Linux and *BSD much better than Windows at http://www.guninski.com/vvfreebsd.html.
- BID-3007: FreeBSD exec() Inherited Signal Handler Vulnerability
- CVE-2001-1180: FreeBSD 4.3 does not properly clear shared signal handlers when executing a process, which allows local users to gain privileges by calling rfork with a shared signal handler, having the child process execute a setuid program, and sending a signal to the child.
- OSVDB ID: 1897: FreeBSD exec() Inherited Signal Handler
- US-CERT VU#943633: FreeBSD can be compromised locally via signal handlers
Reported:
Jul 10, 2001
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