Summary

• A vulnerability in the XCP Router service of the Cisco Unified Communications Manager IM & Presence Service (CUCM IM&P) and the Cisco TelePresence Video Communication Server (VCS) and Expressway could allow an unauthenticated, remote attacker to cause a temporary service outage for all IM&P users, resulting in a denial of service (DoS) condition.

  The vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending a malicious IPv4 or IPv6 packet to an affected device on TCP port 7400. An exploit could allow the attacker to overread a buffer, resulting in a crash and restart of the XCP Router service.

  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-20180815-ucmimps-dos

Affected Products

• Vulnerable Products

  This vulnerability affects all releases of the following Cisco products prior to their respective first fixed release:

  • Cisco Unified Communications Manager IM & Presence Service
  • Cisco TelePresence Video Communication Server (VCS) and Expressway with Unified Communications mode set to Mobile and Remote Access

  Identifying the Unified Communications Manager IM & Presence Service Version

  To determine whether a vulnerable version of the Cisco Unified Communications Manager IM & Presence Service is running on a device, administrators can use the show version active command in the command-line interface (CLI) for the device.
  
  The following example shows the output from a device that is running Cisco Unified Communications Manager IM & Presence Service version 11.5(1):

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

  Identifying the Cisco TelePresence VCS and Expressway Version

  Administrators can log in to the web-based GUI of Cisco TelePresence VCS and Expressway and view the current version in the lower-right corner in the Version field. Alternatively, administrators can view the Software version field by navigating to Status > System > Information.
  

  Identifying the Cisco TelePresence VCS and Expressway Unified Communications mode

  To identify the current Unified Communications mode on Cisco TelePresence VCS and Expressway, administrators can log in to the web-based GUI of the system and look for the current setting of the Unified Communications mode option under Configuration > Unified Communications > Configuration.

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

  Cisco has confirmed that this vulnerability does not affect Cisco WebEx Messenger Service.

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:
  https://www.cisco.com/c/en/us/products/end-user-license-agreement.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:
  https://www.cisco.com/c/en/us/support/web/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 should upgrade to an appropriate release as indicated in the following tables:

  Cisco Unified Communications Manager IM & Presence Service

  Cisco CUCM IM&P Service Major Release	First Fixed Release
  10.5(1) and earlier	Migrate to 11.5(1)SU4
  10.5(2)	10.5(2)SU (Future release)
  11.0(1)	Migrate to 11.5(1)SU4
  11.5(1)	11.5(1)SU4
  12.0(1)	12.0.1.21000-31

  ¹ This release is not publicly available on Cisco.com. Please contact Cisco TAC if you need this release.
  
  Cisco TelePresence Video Communication Server (VCS) and Expressway

  Cisco TelePresence VCS and Expressway Major Release	First Fixed Release
  X7 and earlier	Migrate to X8.11
  X8	X8.11

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 Cisco TAC support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180815-ucmimps-dos

Revision History

• Version	Description	Section	Status	Date
  1.1	Corrected the first fixed release for CUCM IM&P 12.0(1)	Fixed Software	Final	2018-September-04
  1.0	Initial public release.	-	Final	2018-August-15

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