Cisco Security Advisory: Vulnerabilities in Cisco Firewall Services Module

Cisco Security Advisory – Firewall Services Module

Cisco has released a security advisory that deals with certain vulnerabilities found in its Cisco Firewall Services Module (FWSM), that could allow hackers to create a Denial of Service condition.

According to the advisory, the vulnerabilities affect the Cisco Firewall Services Modules software in Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers. The advisory also offers software updates and workarounds that counter the vulnerabilities found in versions 3.x and 4.x of Cisco FWSM software.

The SunRPC Inspection Denial of Service vulnerabilities affect the Cisco FWSM software only when SunRPC Inspection is enabled on the software. Customers can check whether SunRPC Inspection is enabled or not by using the ‘show service-policy | include sunrpc’ command. Cisco warned that the software was affected with three vulnerabilities that were capable of reloading the device when differently crafted SunRPC messages were processed with SunRPC Inspection enabled. The company also reported that the vulnerabilities could be initiated only by transit traffic in the device and not by the traffic which is meant for it.

Meanwhile, the TCP Denial of Service vulnerability affects those versions of Cisco FWSM software which have been configured with multi-mode and with ASDM Administrative Access, Telnet or SSH features. Cisco has given a list of commands on its advisory page that help determine whether the software has been configured with multi-mode or not. The Denial of Service vulnerability affecting the device was capable of reloading it when an attacker sends multiple TCP packets.

The US Computer Emergency Readiness Team has advised customers of Cisco’s Firewall Services Module to thoroughly review the security advisory released by Cisco and apply patches and workarounds if necessary.

More Information on the Cisco Firewall Advisory is available at:

http://www.cisco.com/en/US/products/products_security_advisory09186a0080b3f130.shtml