Microsoft Windows Server 2003 SP2, Server 2008 SP2 and R2 SP1, and Server 2012 Gold and R2 allow remote attackers to cause a denial of serv…

Microsoft Windows Server 2003 SP2, Server 2008 SP2 and R2 SP1, and Server 2012 Gold and R2 allow remote attackers to cause a denial of service (system hang and RADIUS outage) via crafted username strings to (1) Internet Authentication Service (IAS) or (2) Network Policy Server (NPS), aka "Network Policy Server RADIUS Implementation Denial of Service Vulnerability."