Cisco IOS XR Software OSPF Link State Advertisement PCE Vulnerability

Summary

• A vulnerability in Open Shortest Path First (OSPF) Link State Advertisement (LSA) handling by Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
  
  The vulnerability is due to the number of OSPF Path Computation Elements (PCEs) that are configured for an OSPF LSA opaque area update. An attacker could exploit this vulnerability by sending a crafted OSPF LSA update to an affected device that is running the vulnerable software and OSPF configuration. A successful exploit could allow the attacker to cause a DoS condition due to the OSPF process restarting when the crafted OSPF LSA update is received.
  
  Cisco has released software updates that address this vulnerability. Workarounds that mitigate this vulnerability are available.
  
  This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160104-iosxr

Affected Products

• Vulnerable Products

  Cisco IOS XR Software Releases 4.1.1, 4.2.0, 4.2.3, 4.3.0, 4.3.2, 5.0.0, 5.1.0, 5.2.0, 5.2.2, 5.2.4, 5.3.0, and 5.3.2 are vulnerable.

  Products Confirmed Not Vulnerable

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

Indicators of Compromise

• This vulnerability will cause the affected device to reload and generate a core file for the OSPF process. To determine whether the device was compromised by this vulnerability, the core file should be reviewed by the Cisco Technical Assistance Center (TAC).

Workarounds

• To work around this vulnerability, verify that no more than 10 PCEs are configured in a single OSPF area.
  

Fixed Software

• 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 upgrade 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-20160104-iosxr

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated Affected Products.	Affected Products	Final	2016-January-14
  1.0	Initial public release.	-	Final	2016-January-04

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