Many networks employ Cisco Adaptive Security Appliances (ASA) as firewalls or to set up Virtual Private Networks, etc. Those of you that are among this group should be aware that Cisco published a critical security advisory on February 10 concerning a glitch in their ASA software. It seems that there is a vulnerability in the Internet Key Exchange (IKE) code of Cisco ASA Software that could potentially allow an unauthenticated attacker to gain full control of the system, or to cause a reload of the system.
This vulnerability is due to a buffer overflow condition in the function that processes fragmented IKE payloads. Attackers could exploit the flaw by sending crafted UDP packets to the affected system. It should be noted that this vulnerability is bad enough that it was given a maximum CVSS score of 10.
The ASA software on the following products may be affected by this vulnerability:
• Cisco ASA 5500 Series Adaptive Security Appliances
• Cisco ASA 5500-X Series Next-Generation Firewalls
• Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
• Cisco ASA 1000V Cloud Firewall
• Cisco Adaptive Security Virtual Appliance (ASAv)
• Cisco Firepower 9300 ASA Security Module
• Cisco ISA 3000 Industrial Security Appliance
Patches are now available for this flaw. We recommend that vulnerable users of this software apply these patches as soon as possible. For more information see: