TITLE: FreeBSD "pf" IP Fragment Denial of Service Vulnerability
SECUNIA ADVISORY ID: SA18609
VERIFY ADVISORY: http://secunia.com/advisories/18609/
CRITICAL: Moderately critical
WHERE: >From remote
OPERATING SYSTEM: FreeBSD 6.x http://secunia.com/product/6778/ FreeBSD 5.x http://secunia.com/product/1132/
DESCRIPTION: A vulnerability has been reported in FreeBSD, which can be exploited by malicious people to cause a DoS (Denial of Service).
The vulnerability is caused due to an error in the "pf" Internet Protocol packet-filter fragment cache when handling IP fragments. This can be exploited to crash the system by sending a specially-crafted sequence of IP packet fragments to the packet filter.
Successful exploitation requires that "pf" is used with a ruleset containing "scrub fragment crop" or "scrub fragment drop-ovl" rules.
The vulnerability has been reported in version 5.3, 5.4, and 6.0.
SOLUTION: Update FreeBSD or apply patch.
Fixed versions: 2006-01-25 10:00:59 UTC (RELENG_6, 6.0-STABLE) 2006-01-25 10:01:26 UTC (RELENG_6_0, 6.0-RELEASE-p4) 2006-01-25 10:01:47 UTC (RELENG_5, 5.4-STABLE) 2006-01-25 10:02:07 UTC (RELENG_5_4, 5.4-RELEASE-p10) 2006-01-25 10:02:27 UTC (RELENG_5_3, 5.3-RELEASE-p25)
Patch for FreeBSD 5.3, 5.4, and 6.0: ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:07/pf.patch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:07/pf.patch.asc
PROVIDED AND/OR DISCOVERED BY: The vendor credits Jakob Schlyter and Daniel Hartmeier.
ORIGINAL ADVISORY: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:07.pf.asc
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