Cisco IOS and IOS XE Software DNS Forwarder Denial of Service Vulnerability

A vulnerability in the DNS forwarder functionality of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, corrupt the information present in the device’s local DNS cache, or read part of the process memory.

The vulnerability is due to a flaw in handling crafted DNS response messages. An attacker could exploit this vulnerability by intercepting and crafting a DNS response message to a client DNS query that was forwarded from the affected device to a DNS server. A successful exploit could cause the device to reload, resulting in a denial of service (DoS) condition or corruption of the local DNS cache information.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-dns [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-dns”]

This advisory is part of the September 28, 2016, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 10 Cisco Security Advisories that describe 11 vulnerabilities. All the vulnerabilities have a Security Impact Rating of “High.” For a complete list of the advisories and links to them, see Cisco Event Response: September 2016 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication [“https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-56513”].