Cisco ASA Software DNS Denial of Service Vulnerability

A vulnerability in the DNS 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 processing of DNS packets. An attacker could exploit this vulnerability by
sending a request to an affected Cisco ASA appliance to cause it to
generate a DNS request packet. The attacker would need to spoof the reply packet with a crafted DNS response.

Note: Only traffic directed to the affected device can be used to exploit this vulnerability. This vulnerability affects Cisco ASA Software configured in routed or transparent firewall mode and single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic.

This vulnerability is documented in Cisco bug ID CSCut03495[“https://bst.cloudapps.cisco.com/bugsearch/bug/CSCut03495”] (registered[“https://sec.cloudapps.cisco.comRPF/register/register.do”] customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2015-6325.

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-dns1[“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151021-asa-dns1”]