[c-nsp] Cisco Security Advisory: Cisco Unified Communications Manager Denial of Service Vulnerabilities

Wed Mar 3 10:45:00 EST 2010

Cisco Unified Communications Manager (formerly Cisco CallManager)
contains multiple denial of service (DoS) vulnerabilities that if
exploited could cause an interruption of voice services. The Session
Initiation Protocol (SIP), Skinny Client Control Protocol (SCCP) and
Computer Telephony Integration (CTI) Manager services are affected by
these vulnerabilities.

To address these vulnerabilities, Cisco has released free software
updates for select Cisco Unified Communications Manager versions.
There is a workaround for of one the vulnerabilities.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20100303-cucm.shtml

Affected Products
=================

Vulnerable Products
+------------------

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

  * Cisco Unified Communications Manager 4.x
  * Cisco Unified Communications Manager 5.x
  * Cisco Unified Communications Manager 6.x
  * Cisco Unified Communications Manager 7.x

Note: Cisco Unified Communications Manager version 5.1 reached the
End of Software Maintenance on February 13, 2010. For customers using
Cisco Unified Communications Manager 5.x versions, please contact
your 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 8.0(1) and Cisco Unified
Communications Manager Express are not affected by these
vulnerabilities. No other Cisco products are currently known to be
affected by these vulnerabilities.

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.

Malformed SCCP Message Vulnerabilities
+-------------------------------------

Cisco Unified Communications Manager contains two DoS vulnerabilities
that involve the processing of SCCP packets. Each vulnerability is
triggered by a malformed SCCP message that could cause a critical
process to fail, which could result in the disruption of voice
services. All SCCP ports (TCP ports 2000 and 2443) are affected.

The first SCCP DoS vulnerability is documented in Cisco Bug ID 
CSCtc38985 and has been assigned the CVE identifier CVE-2010-0587.
This vulnerability is fixed in Cisco Unified Communications Manager
versions 4.3(2)SR2, 6.1(5), 7.1(3a)su1 and 8.0(1).

The second SCCP DoS vulnerability is documented in Cisco Bug ID 
CSCtc47823 and has been assigned the CVE identifier CVE-2010-0588.
This vulnerability is fixed in Cisco Unified Communications Manager
versions 6.1(5), 7.1(3a)su1 and 8.0(1). Cisco Unified Communications
Manager 4.x versions are not affected.

Malformed SIP Message Vulnerabilities
+------------------------------------

Cisco Unified Communications Manager contains two DoS vulnerabilities
that involve the processing of SIP messages. Each vulnerability is
triggered by a malformed SIP message that could cause a critical
process to fail, which could result in the disruption of voice
services. All SIP ports (TCP ports 5060 and 5061, UDP ports 5060 and
5061) are affected.

The first SIP DoS vulnerability is documented in Cisco Bug ID 
CSCtc37188 and has been assigned the CVE identifier CVE-2010-0590.
This vulnerability is fixed in Cisco Unified Communications Manager
versions 7.1(3a)su1 and 8.0(1) . Cisco Unified Communications Manager
4.x and 6.x versions are not affected.

The second SIP DoS vulnerability is documented in Cisco Bug ID 
CSCtc62362 and has been assigned the CVE identifier CVE-2010-0591.
The second vulnerability is fixed in Cisco Unified Communications Manager
versions 6.1(5), 7.1(3b)SU2 and 8.0(1). Cisco Unified Communications
Manager 4.x versions are not affected.

Malformed CTI Manager Message Vulnerability
+------------------------------------------

The CTI Manager service of Cisco Unified Communications Manager
contains a DoS vulnerability. A malformed message sent to the CTI
Manager service port (TCP 2748) could cause the CTI Manager service
to fail, which could result in the interruption of CTI applications.
The CTI Manager service is disabled by default.

The CTI Manager vulnerability is documented in Cisco Bug ID 
CSCsu31800 and has been assigned the CVE identifier CVE-2010-0592.
This vulnerability is fixed in Cisco Unified Communications Manager
versions 4.3(2)sr1a, 6.1(3), 7.0(2), 7.1(2) and 8.0(1).

Vulnerability Scoring Details
=============================

Cisco has provided scores for the vulnerabilities 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

CSCtc38985 - CCM Coredump on SCCP StationCapabilitiesRes Message with MaxCap Exceeded

CVSS Base Score - 7.8

Access Vector           - Network
Access Complexity       - Low
Authentication          - None
Confidentiality Impact  - None
Integrity Impact        - None
Availability Impact     - Complete

CVSS Temporal Score - 6.4

Exploitability          - Functional
Remediation Level       - Official-Fix
Report Confidence       - Confirmed

CSCtc47823 - CCM Core at invalid Line# in SCCP RegAvailableLines and FwdStatReq

CVSS Base Score - 7.8

Access Vector           - Network
Access Complexity       - Low
Authentication          - None
Confidentiality Impact  - None
Integrity Impact        - None
Availability Impact     - Complete

CVSS Temporal Score - 6.4

Exploitability          - Functional
Remediation Level       - Official-Fix
Report Confidence       - Confirmed

CSCtc37188 - CMSIPUtility Coredump on Fuzzed Register Message

CVSS Base Score - 7.8

Access Vector           - Network
Access Complexity       - Low
Authentication          - None
Confidentiality Impact  - None
Integrity Impact        - None
Availability Impact     - Complete

CVSS Temporal Score - 6.4

Exploitability          - Functional
Remediation Level       - Official-Fix
Report Confidence       - Confirmed

CSCtc62362 - CCM Coredump on Overflow of Field Telephone-URL in REG Msg

CVSS Base Score - 7.8

Access Vector           - Network
Access Complexity       - Low
Authentication          - None
Confidentiality Impact  - None
Integrity Impact        - None
Availability Impact     - Complete

CVSS Temporal Score - 6.4

Exploitability          - Functional
Remediation Level       - Official-Fix
Report Confidence       - Confirmed

CSCsu31800 - CTI crash with invalid packet

CVSS Base Score - 7.8

Access Vector           - Network
Access Complexity       - Low
Authentication          - None
Confidentiality Impact  - None
Integrity Impact        - None
Availability Impact     - Complete

CVSS Temporal Score - 6.4

Exploitability          - Functional
Remediation Level       - Official-Fix
Report Confidence       - Confirmed

Impact
======

Successful exploitation of the vulnerabilities that are described in
this advisory could result in the interruption of voice services. An
affected Cisco Unified Communications Manager services may require a
manual restart to restore voice services.

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.

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.

+---------------------------------------+
| Cisco Unified  |                      |
| Communications | Recommended Release  |
|    Manager     |                      |
|    Version     |                      |
|----------------+----------------------|
| 4.x            | 4.3(2)SR2            |
|----------------+----------------------|
|                | Cisco Unified        |
|                | Communications       |
|                | Manager version 5.1  |
| 5.x            | reached the End of   |
|                | Software Maintenance |
|                | on February 13,      |
|                | 2010.                |
|----------------+----------------------|
| 6.x            | 6.1(5)               |
|----------------+----------------------|
| 7.x            | 7.1(3b)SU2           |
|----------------+----------------------|
|                | Cisco Unified        |
|                | Communications       |
|                | Manager version 8.0  |
|                | (1) was distributed  |
| 8.x            | with software fixes  |
|                | for all the          |
|                | vulnerabilities that |
|                | are described in     |
|                | this advisory.       |
+---------------------------------------+

Cisco Unified Communications Manager software version 4.3(2)SR2 can
be downloaded at the following link:

http://tools.cisco.com/support/downloads/go/PlatformList.x?sftType=Unified+Communications+Manager+Updates&mdfid=280771554&treeName=Voice+and+Unified+Communications&mdfLevel=Software%20Version/Option&url=null&modelName=Cisco+Unified+Communications+Manager+Version+4.3&isPlatform=N&treeMdfId=278875240&modifmdfid=null&imname=&hybrid=Y&imst=N

Cisco Unified Communications Manager software version 6.1(5) can be
downloaded at the following link:

http://tools.cisco.com/support/downloads/go/ReleaseType.x?optPlat=&isPlatform=Y&mdfid=281023410&sftType=Unified+Communications+Manager+Updates&treeName=Voice+and+Unified+Communications&modelName=Cisco+Unified+Communications+Manager+Version+6.1&mdfLevel=Software%20Version/Option&treeMdfId=278875240&modifmdfid=null&imname=&hybrid=Y&imst=N

Cisco Unified Communications Manager software version 7.1(3b)SU2 can
be downloaded at the following link:

http://tools.cisco.com/support/downloads/go/PlatformList.x?sftType=Unified+Communications+Manager+Updates&mdfid=282421166&treeName=Voice+and+Unified+Communications&mdfLevel=Software%20Version/Option&url=null&modelName=Cisco+Unified+Communications+Manager+Version+7.1&isPlatform=N&treeMdfId=278875240&modifmdfid=null&imname=&hybrid=Y&imst=N

Workarounds
===========

Administrators can mitigate the SCCP- and SIP-related vulnerabilities
by implementing filtering on screening devices to permit access to
TCP ports 2000 and 2443, and TCP and UDP ports 5060 and 5061 only
from networks that require SCCP and SIP access to Cisco Unified
Communications Manager appliances.

It is possible to mitigate the CTI Manager vulnerability by disabling
the CTI Manager service t is not necessary; however, this workaround
will interrupt applications that reply on the CTI Manager service.
Administrators can also mitigate the vulnerability by implementing
filtering on screening devices to permit access to TCP port 2748 only
from networks that require access to the CTI Manager service. Please
consult the following documentation for details on disabling Cisco
Unified Communications Manager services:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/service/6_0_1/admin/sasrvact.html#wp1048390

Additional mitigation techniques that can be deployed on Cisco
devices within the network are available in the Cisco Applied
Mitigation Bulletin companion document for this advisory:

http://www.cisco.com/warp/public/707/cisco-amb-20100303-cucm.shtml

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 at cisco.com or security-alert at 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 at 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 vulnerabilities described in this advisory.

The vulnerability documented in Cisco Bug ID CSCtc38985 was reported
to Cisco by the Sipera VIPER Lab. Cisco would like to thank Sipera
VIPER Lab team for reporting this vulnerability to us and for working
with us on a coordinated disclosure.

All other vulnerabilities described in this advisory were discovered
as a result of internal testing conducted by Cisco.

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://www.cisco.com/warp/public/707/cisco-sa-20100303-cucm.shtml

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 at cisco.com
  * first-bulletins at lists.first.org
  * bugtraq at securityfocus.com
  * vulnwatch at vulnwatch.org
  * cisco at spot.colorado.edu
  * cisco-nsp at puck.nether.net
  * full-disclosure at lists.grok.org.uk
  * comp.dcom.sys.cisco at 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 |               | Initial    |
| 1.0      | 2010-March-03 | 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/en/US/products/products_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
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