The firewall engine in Microsoft Forefront Threat Management Gateway, Medium Business Edition (TMG MBE); and Internet Security and Acceleration (ISA) Server 2004 SP3, 2006, 2006 Supportability Update, and 2006 SP1; does not properly manage the session state of web listeners, which allows remote attackers to cause a denial of service (many stale sessions) via crafted packets, aka "Web Proxy TCP State Limited Denial of Service Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6068
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-016
http://www.vupen.com/english/advisories/2009/1030
http://www.us-cert.gov/cas/techalerts/TA09-104A.html
http://www.securitytracker.com/id?1022045