Cisco IOS and IOS XE Software Multicast Routing Denial of Service Vulnerabilities

Multiple vulnerabilities in the multicast subsystem of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to create a denial of service (DoS) condition. The issues are in IPv4 Multicast Source Discovery Protocol (MSDP) and IPv6 Protocol Independent Multicast (PIM).

The first vulnerability (Cisco bug ID CSCud36767[“https://bst.cloudapps.cisco.com/bugsearch/bug/CSCud36767”] (registered[“https://sec.cloudapps.cisco.comRPF/register/register.do”] customers only)) is due to insufficient checking of MSDP Source-Active (SA) messages received from a configured MSDP peer. An attacker who can send traffic to the IPv4 address of a device could exploit this vulnerability by sending a packet designed to trigger the issue to the affected device. A successful exploit could cause the affected device to restart.

The second vulnerability (Cisco bug ID CSCuy16399[“https://bst.cloudapps.cisco.com/bugsearch/bug/CSCuy16399”] (registered[“https://sec.cloudapps.cisco.comRPF/register/register.do”] customers only)) is due to insufficient checking of packets encapsulated in a PIM register message. An attacker who can send a malformed IPv6 PIM register packet to a PIM rendezvous point (RP) could exploit the vulnerability. A successful exploit could cause the affected device to restart.

Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

This advisory is available at the following link:

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

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”].