Cisco ASA Software VPN ISAKMP Denial of Service Vulnerability

A vulnerability in the Internet Key Exchange (IKE) version 1 (v1) code of Cisco Adaptive Security Appliance (ASA) Software could allow an
unauthenticated, remote attacker to cause an affected
system to reload.

The vulnerability is due to improper handling of Internet Security Association and Key Management Protocol (ISAKMP) packets. An
attacker could exploit this vulnerability by sending crafted UDP packets
to the affected system. A successful exploit could allow the attacker to cause an affected system to reload.

Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed firewall mode only and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic.

This vulnerability is documented in Cisco bug ID CSCus94026[“https://bst.cloudapps.cisco.com/bugsearch/bug/CSCus94026”] (registered[“https://sec.cloudapps.cisco.comRPF/register/register.do”] customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2015-6327.

Cisco has released software updates that address this vulnerability. Workarounds that mitigate this vulnerability are not available.
This advisory is available at the following link:

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151021-asa-ike[“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151021-asa-ike”]