Cisco IOS and IOS XE Software Layer 2 Tunneling Protocol Denial of Service Vulnerability

A vulnerability in the Layer 2 Tunneling Protocol (L2TP) parsing function of Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload.

The vulnerability is due to insufficient validation of L2TP packets. An attacker could exploit this vulnerability by sending a crafted L2TP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.
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-20170322-l2tp [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170322-l2tp”]

This advisory is part of the March 22, 2017, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes five Cisco Security Advisories that describe five 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: March 2017 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication [“https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-60851”].