Cisco Internetwork Operating System (IOS) may reload unexpectedly after being scanned on certain ports.
Certain versions of Cisco IOS contain a vulnerability that allows the router to enter an unstable state after receiving a connection attempt on any TCP port in the following ranges: 3100-3999, 5100-5999, 7100-7999, and 10100-10999. In this state, the router will reload at the next execution of "show running-config," "write memory," or any command that causes the configuration file to be accessed.
Attackers may cause Cisco routers to reload and cause a denial of service.
Review Cisco Systems's security advisory to determine which versions of IOS are vulnerable and which version you should obtain to eliminate this vulnerability. The advisory is available at:
Thanks to Cisco Systems for reporting this vulnerability.
This document was written by Shawn Van Ittersum.
|Date First Published:||2001-10-25|
|Date Last Updated:||2001-10-25 23:44 UTC|