Summary

• A vulnerability in the SIP call processing function of Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

  This vulnerability is due to improper parsing of SIP messages. An attacker could exploit this vulnerability by sending a crafted SIP message to an affected Cisco Unified CM or Cisco Unified CM SME device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition that interrupts the communications of reliant voice and video devices.

  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-cucm-dos-kkHq43We

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco Unified CM and Cisco Unified CM SME, regardless of device configuration.

  For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.

  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 the following Cisco products:

  • CallManager Express (CME)
  • Emergency Responder
  • IOS Software
  • IOS XE Software
  • Jabber Client
  • Packaged Contact Center Enterprise (PCCE) (including Outbound Dialer)
  • Prime Collaboration Deployment (PCD)
  • Prime License Manager (PLM)
  • Unified Border Element (CUBE)
  • Unified Communications Manager IM & Presence Service (Unified CM IM&P)
  • Unified Contact Center Enterprise (UCCE) (including Outbound Dialer)
  • Unified Contact Center Express (UCCX)
  • Unified Customer Voice Portal (CVP)
  • Unity Connection
  • Virtualized Voice Browser (VVB)
  • Voice Extensible Markup Language (VXML) Gateway

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 with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.

  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.

  The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.

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

  In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.

  Cisco Unified CM and Unified CM SME Release	First Fixed Release
  12.5(1)	12.5(1)SU9
  14	14SU4
  15	15SU1

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

Exploitation and Public Announcements

• The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

Source

• Cisco would like to thank the U.S. National Security Agency (NSA) for reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-dos-kkHq43We

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2024-AUG-21

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