Cisco Security Advisory: Cisco Unified Communications Manager Express Vulnerability

23 Sep 2009

Cisco IOS� devices that are configured for Cisco Unified
Communications Manager Express (CME) and the Extension Mobility
feature are vulnerable to a buffer overflow vulnerability. Successful
exploitation of this vulnerability may result in the execution of
arbitrary code or a Denial of Service (DoS) condition on an affected
device.

Cisco has released free software updates that address this
vulnerability.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20090923-cme.shtml

Note: The September 23, 2009, Cisco IOS Security Advisory bundled
publication includes eleven Security Advisories. Ten of the
advisories address vulnerabilities in Cisco IOS Software, and one
advisory addresses a vulnerability in Cisco Unified Communications
Manager. Each advisory lists the releases that correct the
vulnerability or vulnerabilities detailed in the advisory. The
following table lists releases that correct all Cisco IOS Software
vulnerabilities that have been published on September 23, 2009, or
earlier.

http://www.cisco.com/warp/public/707/cisco-sa-20090923-bundle.shtml

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

http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep09.html

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

Cisco IOS devices, including Cisco Unified Communications 500 Series,
that are configured for Cisco Unified CME and the Extension Mobility
feature are affected.

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

A Cisco IOS device that is configured for Cisco Unified CME and
Extension Mobility contains the following output when the show
running-config command is issued:

    ephone [Ethernet phone tag]
      ...
      logout-profile [logout-profile tag]

To determine the Cisco IOS Software release that is running on a
Cisco product, administrators can log in to the device and issue the 
"show version" command to display the system banner. The system banner
confirms that the device is running Cisco IOS Software by displaying
text similar to "Cisco Internetwork Operating System Software" or
"Cisco IOS Software." The image name is displayed in parentheses,
followed by "Version" and the Cisco IOS Software release name. Other
Cisco devices do not have the "show version" command or may provide
different output.

The following example identifies a Cisco product that is running
Cisco IOS Software Release 12.3(26) with an installed image name of
C2500-IS-L:

        Router#show version
        Cisco Internetwork Operating System Software
        IOS (tm) 2500 Software (C2500-IS-L), Version 12.3(26), RELEASE SOFTWARE (fc2)
        Technical Support: http://www.cisco.com/techsupport
        Copyright (c) 1986-2008 by cisco Systems, Inc.
        Compiled Mon 17-Mar-08 14:39 by dchih

        <output truncated>

The following example identifies a Cisco product that is running
Cisco IOS Software Release 12.4(20)T with an installed image name of
C1841-ADVENTERPRISEK9-M:

        Router#show version
        Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 12.4(20)T, RELEASE SOFTWARE (fc3)
        Technical Support: http://www.cisco.com/techsupport
        Copyright (c) 1986-2008 by Cisco Systems, Inc.
        Compiled Thu 10-Jul-08 20:25 by prod_rel_team

        <output truncated>

Additional information about Cisco IOS Software release naming
conventions is available in "White Paper: Cisco IOS Reference Guide"
at the following link: http://www.cisco.com/warp/public/620/1.html .

Products Confirmed Not Vulnerable
+--------------------------------

Cisco IOS devices that are configured for Survivable Remote Site
Telephony (SRST) Mode are not affected.

Cisco IOS XR is not affected.

Cisco IOS XE is not affected.

Cisco Unified Communications Manager is not affected.

Cisco Unified CME is not affected unless configured to use the
Extension Mobility feature.

No other Cisco products are currently known to be affected by these
vulnerabilities.

Details
=======

Cisco Unified CME is the call processing component of an enhanced IP
telephony solution that is integrated into Cisco IOS.

The Extension Mobility feature in Cisco Unified CME provides the
benefit of phone mobility for end users. A user login service allows
phone users to temporarily access a physical phone other than their
own phone and utilize their personal settings, such as directory
number, speed-dial lists, and services, that is assigned to their own
desk phone. The phone user can make and receive calls on that phone
using the same personal directory number as is on their own desk
phone. More information on Extension Mobility feature is available at
the following URL:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guid...

A vulnerability in the login section of the Extension Mobility
feature may allow an unauthenticated attacker to execute arbitrary
code or cause a Denial of Service (DoS) condition. Such packets can
only come from registered phone IP addresses in the form of HTTP
requests. If the auto-registration feature is enabled, an attacker
can register its IP address and subsequently send a crafted payload
to exploit this vulnerability. The auto-registration feature is
enabled by default. More information on auto-registration can be
found at the following link:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/command/reference/cme_a1....

This vulnerability is addressed by the Cisco Bug ID CSCsq58779 and has
been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2009-2865.

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

CSCsq58779 - Vulnerability in Extension Mobility Feature

CVSS Base Score - 7.6

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

CVSS Temporal Score - 6.3

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

Impact
======

Successful exploitation of this vulnerability may result in the
execution of arbitrary code or a Denial of Service (DoS) condition on
an affected device.

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.

Each row of the Cisco IOS software table (below) names a Cisco IOS
release train. If a given release train is vulnerable, then the
earliest possible releases that contain the fix (along with the
anticipated date of availability for each, if applicable) are listed
in the "First Fixed Release" column of the table. The "Recommended
Release" column indicates the releases which have fixes for all the
published vulnerabilities at the time of this Advisory. A device
running a release in the given train that is earlier than the release
in a specific column (less than the First Fixed Release) is known to
be vulnerable. Cisco recommends upgrading to a release equal to or
later than the release in the "Recommended Releases" column of the
table.

+-------------------------------------------------------------------+
|    Major Release     |        Availability of Repaired Releases   |
|----------------------+--------------------------------------------|
| Affected 12.0-Based  |  First Fixed  |    Recommended Release     |
|       Releases       |    Release    |                            |
|-------------------------------------------------------------------|
| There are no affected 12.0 based releases.                        |
|-------------------------------------------------------------------|
| Affected 12.1-Based  |  First Fixed  |    Recommended Release     |
|       Releases       |    Release    |                            |
|-------------------------------------------------------------------|
| There are no affected 12.1 based releases.                        |
|-------------------------------------------------------------------|
| Affected 12.2-Based  |  First Fixed  |    Recommended Release     |
|       Releases       |    Release    |                            |
|-------------------------------------------------------------------|
| There are no affected 12.2 based releases.                        |
|-------------------------------------------------------------------|
| Affected 12.3-Based  |  First Fixed  |    Recommended Release     |
|       Releases       |    Release    |                            |
|-------------------------------------------------------------------|
| There are no affected 12.3 based releases.                        |
|-------------------------------------------------------------------|
| Affected 12.4-Based  |  First Fixed  |    Recommended Release     |
|       Releases       |    Release    |                            |
|----------------------+---------------+----------------------------|
| 12.4                 | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4GC               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JA               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JDA              | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JDC              | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JDD              | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JK               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JL               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JMA              | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JMB              | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4JX               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4MD               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4MDA              | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4MR               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4SW               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4T                | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XA               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XB               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XC               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XD               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XE               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XF               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XG               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XJ               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XK               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XL               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XM               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XN               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XP               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XQ               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XR               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XT               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4XV               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
|                      |               | 12.4(20)T4                 |
|                      |               |                            |
| 12.4XW               | 12.4(11)XW8   | 12.4(22)T3                 |
|                      |               |                            |
|                      |               | 12.4(24)T2; Available on   |
|                      |               | 23-OCT-2009                |
|----------------------+---------------+----------------------------|
|                      |               | 12.4(20)T4                 |
|                      |               |                            |
| 12.4XY               | 12.4(15)XY4   | 12.4(22)T3                 |
|                      |               |                            |
|                      |               | 12.4(24)T2; Available on   |
|                      |               | 23-OCT-2009                |
|----------------------+---------------+----------------------------|
|                      |               | 12.4(20)T4                 |
|                      |               |                            |
| 12.4XZ               | 12.4(15)XZ1   | 12.4(22)T3                 |
|                      |               |                            |
|                      |               | 12.4(24)T2; Available on   |
|                      |               | 23-OCT-2009                |
|----------------------+---------------+----------------------------|
|                      |               | 12.4(20)T4                 |
|                      |               |                            |
| 12.4YA               | 12.4(20)YA1   | 12.4(22)T3                 |
|                      |               |                            |
|                      |               | 12.4(24)T2; Available on   |
|                      |               | 23-OCT-2009                |
|----------------------+---------------+----------------------------|
| 12.4YB               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4YD               | Not           |                            |
|                      | Vulnerable    |                            |
|----------------------+---------------+----------------------------|
| 12.4YE               | Not           |                            |
|                      | Vulnerable    |                            |
+-------------------------------------------------------------------+

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

There are no workarounds to mitigate this vulnerability, other than
disabling Extension Mobility. However, auto-registration can be
disabled to make exploitation more difficult. Auto-registration can
be disabled by the following command:

    telephony-service 
      no auto-reg-ephone 

Before disabling auto-registration, all phone MAC addresses need to
be explicitly defined on the Cisco Unified CME. Otherwise phones will
not be able to register. More information on auto-registration can be
found at the following link:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/command/reference/cme_a1...

Additional mitigations that can be deployed on Cisco devices in the
network are available in the Cisco Applied Mitigation Bulletin
companion document for this advisory, which is available at the
following link:

http://www.cisco.com/warp/public/707/cisco-amb-20090923-cme.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@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 internally.

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-20090923-cme.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@cisco.com
  * first-bulletins@lists.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 |                   | Initial |
| 1.0      | 2009-September-23 | 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.h...

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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Cisco Security Advisory: Cisco Unified Communications Manager Express Vulnerability

Cisco Systems Product Security Incident Response Team