Cisco released information detailing a vulnerability in Cisco Catalyst 6500 Series Switch and Cisco 7600 Series Router. Malformed IKE Packets will cause the router to crash and reboot presenting an opportunity for sustained DoS attempts against this hardware. Full details of which software versions are vulnerable and under what circumstances can be found at:

http://www.cisco.com/warp/public/707/cisco-sa-20040408-vpnsm.shtml

For software versions that are vulnerable, there is no work around - you must patch.

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Hander On Duty, Davis Ray Sickmon, Jr ( http://www.midnightryder.com )