Summary

• A vulnerability in the Session Initiation Protocol (SIP) UDP throttling process of Cisco Unified Communications Manager (Cisco Unified CM) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
  
  The vulnerability is due to insufficient rate limiting protection. An attacker could exploit this vulnerability by sending the affected device a high rate of SIP messages. An exploit could allow the attacker to cause the device to reload unexpectedly. The device and services will restart automatically.
  
  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-20170419-ucm

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco Unified Communications Manager (CallManager) releases prior to the first fixed release. For information about fixed releases, see the Fixed Software section of this advisory.
  
  To determine the release of Cisco Unified Communications Manager running on a device, administrators can use the show version active command in the CLI of the device.
  
  The following example shows the output from a device that is running Release 11.5(1) of the service:
  

  admin: show version active
  Active Master Version: 11.5.1.10000-4
  Active Version Installed Software Options:
  No Installed Software Options Found.

  
  

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.
  
  Cisco has confirmed that Cisco Unified CM Releases 9.x and earlier are not affected by this vulnerability.

Workarounds

• There are no workarounds that address this vulnerability.
  

Fixed Software

• Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
  http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html

  Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.

  When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, 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.

  Customers Without Service Contracts

  Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
  http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html

  Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.

  Fixed Releases

  Customers are advised to install an appropriate fixed release as indicated in this section.
  
  The following list indicates the first minor release that includes the fix for this this vulnerability:

  • 10.5.2.14900-16
  • 11.0.1.23900-5
  • 11.5.1.12900-21

  Customers can download software for the Cisco Unified Communication Manager Service from the Software Center on Cisco.com by navigating to Products > Unified Communications > Call Control > Unified Communications Manager (CallManager).

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.

Source

• This vulnerability was found during the resolution of a support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170419-ucm

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated the first fixed release number for Release 11.5.1.12900.	Fixed Software	Final	2017-April-21
  1.0	Initial public release.	-	Final	2017-April-19

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