Regex Crashes BGP Routers

Posted on in Networking

Cisco LogoThis isn't late breaking information, but there's an interesting post in the Cisco WAN, Routing and Switching Forum regarding a particular regular expression that, when used in conjunction with the show ip bgp regexp, results in a router crash. Here is the full command.

show ip bgp regexp (.*)(_\1)+

The real problem with this command (other than the actual crash, of course) is that it can be issued by anyone with CLI access to the router, and does not require 'enable' access.

The Cisco PSIRT (Product Security Incident Response Team) confirms that this is a problem and they believe it corresponds to bug CSCsb08386. Customers experiencing this problem should open a case with the Cisco TAC and be prepared to provide the output of show tech, crashdumps, and tracebacks.

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