Cisco Firewall Services Module TCP ACL Bypass Vulnerability

Thu May 12 18:36:06 UTC 2005

Via FrSIRT:
 http://www.frsirt.com/english/advisories/2005/0527

- ferg

[snip]

 * Technical Description *

A new vulnerability was identified in Cisco products, which may be exploited by attackers to bypass the security restrictions. The flaw resides in the Cisco Firewall Services Module (FWSM) when configured for exceptions in content filtering, which may be exploited by attackers to bypass access-list entries intended to explicitly filter inbound TCP packets.

 * Affected Products *

Catalyst 6500 series switches
Cisco 7600 series routers 

 * Solution *

Upgrade to Cisco FWSM version 2.3(2) :
http://www.cisco.com/warp/public/707/cisco-sa-20050511-url.shtml

[snip]

--
"Fergie", a.k.a. Paul Ferguson
 Engineering Architecture for the Internet
 fergdawg at netzero.net or fergdawg at sbcglobal.net
 ferg's tech blog: http://fergdawg.blogspot.com/