Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later packets because they appear to be too old.
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:15.tcp.asc
ftp://ftp.sco.com/pub/updates/UnixWare/SCOSA-2005.64/SCOSA-2005.64.txt
secunia.com/advisories/15393
secunia.com/advisories/15417/
secunia.com/advisories/18222
secunia.com/advisories/18662
support.avaya.com/elmodocs2/security/ASA-2006-032.htm
www.cisco.com/warp/public/707/cisco-sn-20050518-tcpts.shtml
www.kb.cert.org/vuls/id/637934
www.securityfocus.com/bid/13676
exchange.xforce.ibmcloud.com/vulnerabilities/20635