Efficient Networks 5861 DSL router, when running firmware 5.3.80 configured to block incoming TCP SYN, packets allows remote attackers to cause a denial of service (crash) via a flood of TCP SYN packets to the WAN interface using a port scanner such as nmap.
http://www.securitytracker.com/id?1005910
http://www.securityfocus.com/bid/6573
http://www.securityfocus.com/archive/1/308008
http://www.securityfocus.com/archive/1/306081
http://www.iss.net/security_center/static/11032.php
http://securitytracker.com/id?1005980
http://archives.neohapsis.com/archives/vulnwatch/2003-q1/0015.html