This indicates a possible attempt to exploit a Denial of Service vulnerability in the Microsoft Windows kernel.
The vulnerability is in the TCP/IP code, and is a result of the way that the Windows kernel processes fragmented "router advertisement" ICMP queries. It can be exploited to cause a computer to stop responding and automatically restart.
Microsoft Windows 2000 Service Pack 4
Windows XP Service Pack 2
Windows XP Professional x64 Edition
Windows XP Professional x64 Edition Service Pack 2
Windows Server 2003 Service Pack 1
Windows Server 2003 Service Pack 2
Windows Server 2003 x64 Edition
Windows Server 2003 x64 Edition Service Pack 2
Windows Server 2003 with SP1 for Itanium-based Systems
Windows Server 2003 with SP2 for Itanium-based Systems
Windows Vista x64 Edition
Denial of service.
Apply the patch available from the Web site.