TITLE: FreeBSD SACK Handling Denial of Service SECUNIA ADVISORY ID: SA18696 VERIFY ADVISORY: http://secunia.com/advisories/18696/ CRITICAL: Moderately critical IMPACT: DoS WHERE: >From remote OPERATING SYSTEM: 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 SACK (Selective ACKnowledgement) handling and may result in an infinite loop when not enough memory is available to handle an incoming SACK. This can be exploited by opening up a TCP connection to a vulnerable system and sending a specially crafted series of TCP packets. Successful exploitation causes the TCP/IP stack to enter an infinite loop. SOLUTION: Update FreeBSD or apply patch. Fixed versions: 2006-01-24 01:16:18 UTC (RELENG_5, 5.4-STABLE) 2006-02-01 19:43:10 UTC (RELENG_5_4, 5.4-RELEASE-p11) 2006-02-01 19:43:36 UTC (RELENG_5_3, 5.3-RELEASE-p26) Patch for FreeBSD 5.3 and 5.4: ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:08/sack.patch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:08/sack.patch.asc PROVIDED AND/OR DISCOVERED BY: The vendor credits Scott Wood. ORIGINAL ADVISORY: ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:08.sack.asc ---------------------------------------------------------------------- About: This Advisory was delivered by Secunia as a free service to help everybody keeping their systems up to date against the latest vulnerabilities. Subscribe: http://secunia.com/secunia_security_advisories/ Definitions: (Criticality, Where etc.) http://secunia.com/about_secunia_advisories/ Please Note: Secunia recommends that you verify all advisories you receive by clicking the link. Secunia NEVER sends attached files with advisories. Secunia does not advise people to install third party patches, only use those supplied by the vendor. ---------------------------------------------------------------------- Unsubscribe: Secunia Security Advisories http://secunia.com/sec_adv_unsubscribe/?email=packet%40packetstormsecurity.org ----------------------------------------------------------------------