Cisco Carrier Routing System IPv6 Denial of Service Vulnerability

Summary

• A vulnerability in IPv6 over MPLS packet processing of Cisco IOS XR for Cisco Carrier Routing System (CRS) platforms could allow an unauthenticated, adjacent attacker to cause a reload of the affected line card.
  
  The vulnerability is due to insufficient logic in processing of crafted IPv6 over MPLS packets. An attacker could exploit this vulnerability by sending a crafted IPv6 over MPLS packet to be processed by an affected device. An exploit could allow the attacker to cause a reload of the affected line card.
  
  Cisco has not released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
  
  This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160914-crs

Affected Products

• Vulnerable Products

  Cisco CRS Carrier Grade Services for CRS-1 and CRS-3 are affected. For information about affected releases, see the associated Cisco bug, which is accessible through the Cisco Bug Search Tool.
  
  Cisco CRS running an affected version of IOS XR and configured to process IPv6 over MPLS packets is affected. The affected router must strip the MPLS label and parse the crafted IPv6 packet. IPv6 packets received without an MPLS label do not trigger the vulnerability.
  
  On line cards based on CRS-1 or CRS-3, the processing of the packets will result in a crash. On cards based on CRS-X, packet processing will result in a packet processing engine (PPE) dump.

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• Cisco provides information about fixed software in Cisco bugs, which are accessible through the Cisco Bug Search Tool.

  
  When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
  
  In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

Exploitation and Public Announcements

• The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

URL

• http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160914-crs

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2016-September-14

  Show Less