Cisco IOS and IOS XE Software Internet Key Exchange Version 1 Fragmentation Denial of Service Vulnerability

A vulnerability in the Internet Key Exchange version 1 (IKEv1) fragmentation code of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to cause an exhaustion of available memory or a reload of the affected system.

The vulnerability is due to the improper handling of crafted, fragmented IKEv1 packets. An attacker could exploit this vulnerability by sending crafted UDP packets to the affected system. An exploit could allow the attacker to cause a reload of the affected system.

Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability can be triggered by IPv4 and IPv6 traffic.

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-ios-ikev1 [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-ios-ikev1”]

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”].