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Cisco Firewall Services Module TCP ACL Bypass Vulnerability

  • From: Fergie (Paul Ferguson)
  • Date: Thu May 12 14:39:45 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
 [email protected] or [email protected]
 ferg's tech blog: http://fergdawg.blogspot.com/