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Cisco Unified Communications Manager Memory Leak Vulnerability

Advisory ID: cisco-sa-20110928-cucm

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110928-cucm

Revision 1.1

Last Updated  2012 July 18 14:05  UTC (GMT)

For Public Release 2011 September 28 16:00  UTC (GMT)


Summary

Cisco Unified Communications Manager contains a memory leak vulnerability that could be triggered through the processing of malformed Session Initiation Protocol (SIP) messages. Exploitation of this vulnerability could cause an interruption of voice services. Cisco has released free software updates for supported Cisco Unified Communications Manager versions to address the vulnerability. A workaround exists for this SIP vulnerability.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110928-cucm.

Note: The September 28, 2011, Cisco IOS Software Security Advisory bundled publication includes ten Cisco Security Advisories. Nine of the advisories address vulnerabilities in Cisco IOS Software, and one advisory addresses a vulnerability in Cisco Unified Communications Manager. Each advisory lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as well as the Cisco IOS Software releases that correct all vulnerabilities in the September 2011 Bundled Publication.

Individual publication links are in "Cisco Event Response: Semiannual Cisco IOS Software Security Advisory Bundled Publication" at the following link:

http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep11.html

Cisco IOS Software is affected by the SIP vulnerability described in this advisory. A separate Cisco Security Advisory has been published to disclose the vulnerabilities that affect the Cisco IOS software at the following location: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110928-sip.

Affected Products

Vulnerable Products

The following products are affected by vulnerabilities that are described in this advisory:

  • Cisco Unified Communications Manager 6.x 
  • Cisco Unified Communications Manager 7.x 
  • Cisco Unified Communications Manager 8.x

Note: Cisco Unified Communications Manager version 6.1 reached the End of Software Maintenance on September 3, 2011.  Customers using Cisco Unified Communications Manager 6.x versions, should contact their Cisco support team for assistance in upgrading to a supported version of Cisco Unified Communications Manager.

Products Confirmed Not Vulnerable

Cisco Unified Communications Manager version 4.x is not affected by this vulnerability. No other Cisco products are currently known to be affected by this vulnerability.

Details

Cisco Unified Communications Manager is the call processing component of the Cisco IP Telephony solution that extends enterprise telephony features and functions to packet telephony network devices, such as IP phones, media processing devices, VoIP gateways, and multimedia applications.

Memory Leak Vulnerability in SIP

Cisco Unified Communications Manager contains a vulnerability that involves the processing of SIP messages. Cisco Unified Communications Manager may leak session control buffers (SCBs) or cause a reload of the affected device when processing a malformed SIP message. Exploitation of the vulnerability may cause a critical process to fail, which could result in the disruption of voice services. All SIP ports (TCP ports 5060 and 5061 and UDP ports 5060 and 5061) are affected.

This SIP vulnerability is documented in Cisco Bug ID CSCtl86047 (registered customers only) and has been assigned the CVE identifier CVE-2011-2072. This vulnerability is fixed in Cisco Unified Communications Manager versions 8.6(1), 8.5(1)su2, and 7.1(5b)su4. [Note, there is not a software Service Update for the 6.x version that contains the fix.]

Note: This vulnerability also affects Cisco IOS Software. The corresponding Cisco Bug ID is CSCto88686. Refer to the separate Cisco Security Advisory for the Cisco IOS Software for additional details.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerability in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding CVSS at
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html .

Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at
http://intellishield.cisco.com/security/alertmanager/cvss .


CSCtl86047 (registered customers only

Calculate the environmental score of CSCtl86047
CVSS Base Score - 7.8
Access Vector Access Complexity Authentication Confidentiality Impact Integrity Impact Availability Impact
Network Low None None None Complete
CVSS Temporal Score - 6.4
Exploitability Remediation Level Report Confidence
Functional Official-Fix Confirmed

Impact

Successful exploitation of the vulnerability that is described in this advisory could allow a remote attacker to trigger a device reload that could result in the interruption of voice services. Cisco Unified Communications Manager will restart the affected processes, but repeated attacks may result in a sustained denial of service (DoS) condition.

Software Versions and Fixes

When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table.

In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider for assistance.

Additionally, the Cisco IOS Software Checker is available on the Cisco Security Intelligence Operations (SIO) portal at http://tools.cisco.com/security/center/selectIOSVersion.x. It provides several features for checking which Security Advisories affect specified versions of Cisco IOS Software.

Cisco Unified Communication Manager Version

Recommended Release

7.x

7.1(5b)su4

8.x*

8.5(1)su2, 8.6(1)

*The recommended releases listed in the table above are the latest Cisco Unified Communications Manager versions available at the publication of this advisory. Software updates for 6.1 and 8.0 are not available for CSCtl86047. Customers using these versions should consult their Cisco support team for assistance in upgrading to a supported release.

Cisco Unified Communications Manager software can be downloaded from the following link: http://tools.cisco.com/support/downloads/go/Redirect.x?mdfid=268439621


Workarounds

A workaround exists for customers who do not require SIP in their environment. Cisco Unified Communication Manager versions 6.1(4), 7.1(2) and 8.0(1) introduced the ability to disable SIP processing. SIP processing is enabled by default. Use the following instructions to disable SIP processing:

  • Step 1: Log in to the Cisco Unified CM Administration web interface.
  • Step 2: Navigate to System > Service Parameters and select the appropriate Cisco Unified Communications Manager server and the Cisco CallManager service.
  • Step 3: Change the SIP Interoperability Enabled parameter to False and click Save.

    Note: For a SIP processing change to take effect, the Cisco CallManager Service must be restarted. For information on how to restart the service, refer to the "Restarting the Cisco CallManager Service" section of the document athttp://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/7_1_2/ccmcfg/b03dpi.html#wp1075124 

    It is possible to mitigate these vulnerabilities by implementing filtering on screening devices and permitting access to TCP ports 5060 and 5061 and UDP ports 5060 and 5061 only from networks that require SIP access to Cisco Unified Communications Manager servers. 
    Additional mitigations that can be deployed on Cisco devices in the network are available in the companion document "Cisco Applied Mitigation Bulletin: Identifying and Mitigating Exploitation of the Multiple Vulnerabilities in Cisco Voice Products" which is available at the following location: http://tools.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20110928-voice 

Obtaining Fixed Software

Cisco has released free software updates that address these vulnerabilities. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets they have purchased. By installing, downloading, accessing or otherwise using such software upgrades, customers agree to be bound by the terms of Cisco's software license terms found at http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html , or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml .

Do not contact psirt@cisco.com or security-alert@cisco.com for software upgrades

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com.

Customers using Third Party Support Organizations

Customers whose Cisco products are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.

Customers without Service Contracts

Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts are as follows.

  • +1 800 553 2447 (toll free from within North America)
  • +1 408 526 7209 (toll call from anywhere in the world)
  • e-mail: tac@cisco.com

Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.

Exploitation and Public Announcements

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

This vulnerability was found during internal testing and the troubleshooting of customer service requests.

Status of this Notice: Final

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.


Distribution

This advisory is posted on Cisco's worldwide website at:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110928-cucm

In addition to worldwide web posting, a text version of this notice is clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail and Usenet news recipients.

  • cust-security-announce@cisco.com
  • first-teams@first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk
  • comp.dcom.sys.cisco@newsgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's worldwide website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the above URL for any updates.


Revision History

Revision 1.1 2012-July-18 Updated advisory metatags.
Revision 1.0 2011-September-28 Initial public release.

Cisco Security Procedures

Complete information on reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco, is available on Cisco's worldwide website at http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.