[c-nsp] Cisco Security Advisory: Cisco Unified Communications Manager IP Phone Personal Address Book Synchronizer Privilege Escalation Vulnerability

Wed Mar 11 11:40:00 EDT 2009

Cisco Unified Communications Manager, formerly CallManager, contains
a privilege escalation vulnerability in the IP Phone Personal Address
Book (PAB) Synchronizer feature that may allow an attacker to gain
complete administrative access to a vulnerable Cisco Unified
Communications Manager system. If Cisco Unified Communications
Manager is integrated with an external directory service, it may be
possible for an attacker to leverage the privilege escalation
vulnerability to gain access to additional systems configured to use
the directory service for authentication.

Cisco has released free software updates that address this
vulnerability. Workarounds that mitigate this vulnerability are
available.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20090311-cucmpab.shtml

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

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

The following products are vulnerable:

  * Cisco Unified CallManager 4.1 versions
  * Cisco Unified Communications Manager 4.2 versions prior to 4.2(3)SR4b
  * Cisco Unified Communications Manager 4.3 versions prior to 4.3(2)SR1b
  * Cisco Unified Communications Manager 5.x versions prior to 5.1(3e)
  * Cisco Unified Communications Manager 6.x versions prior to 6.1(3)
  * Cisco Unified Communications Manager 7.0 versions prior to 7.0(2)

Administrators of systems that are running Cisco Unified
Communications Manager software version 4.x can determine the
software version by navigating to Help > About Cisco Unified
CallManager and selecting the Details button via the Cisco Unified
Communications Manager administration interface.

Administrators of systems that are running Cisco Unified
Communications Manager software versions 5.x, 6.x, and 7.x can
determine the software version by viewing the main page of the Cisco
Unified Communications Manager administration interface. The software
version can also be determined by running the command show version
active via the command line interface (CLI).

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

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

Details
=======

The Cisco IP Phone Personal Address Book (PAB) Synchronizer feature
of Cisco Unified Communications Manager allows users to keep their
Cisco Unified Communications Manager address book synchronized with
their Microsoft Windows address book. The IP Phone PAB Synchronizer
feature contains a privilege escalation vulnerability that may allow
an attacker to obtain complete administrative access to a vulnerable
Cisco Unified Communications Manager system. After an IP Phone PAB
Synchronizer client successfully authenticates to a Cisco Unified
Communications Manager device over a HTTPS connection, the Cisco
Unified Communications Manager returns credentials for a user account
that is used to manage the Cisco Unified Communications Manager
directory service. If an attacker is able to intercept the
credentials, they can perform unauthorized modifications to the Cisco
Unified Communications Manager configuration and extend their
privileges. The IP Phone PAB Synchronizer client has been redesigned
to allow address book synchronization without requiring the directory
service credentials. This vulnerability does not allow an attacker to
gain access to the underlying platform operating system of any Cisco
Unified Communications Manager system.

Cisco Unified Communications Manager 4.x
+---------------------------------------

Cisco Unified Communications Manager software version 4.x by default
stores user information using an internal Lightweight Directory
Access Protocol (LDAP) server called DC Directory. After an IP Phone
PAB Synchronizer client successfully authenticates, the Cisco Unified
Communications Manager returns credentials for the DC Directory user
that will be used by the client to synchronize a user's address book.
Depending on how a Cisco Unified Communications Manager is
configured, an attacker may obtain different privilege levels using
the intercepted credentials.

By default, Cisco Unified Communications Manager software version 4.x
administrator accounts are created as part of an underlying Microsoft
Windows operating system. Cisco Unified Communications Manager is
commonly deployed using the Multi-Level Administration (MLA) feature
to ease the integration of Cisco Unified Communications Manager into
enterprise environments. If MLA is enabled, Cisco Unified
Communications Manager stores administrator accounts in the Cisco
Unified Communications Manager DC Directory service. If an attacker
obtains the DC Directory credentials and MLA is enabled, the attacker
can add an existing account to the Cisco Unified Communications
Manager super-user group. The attacker can then access the Cisco
Unified Communications Manager management interface with complete
administrative access. If MLA is not enabled, the attacker cannot
escalate their privileges; however, they can modify any user settings
in the directory.

The Cisco Unified Communications Manager 4.x IP Phone PAB
Synchronizer client uses an unencrypted LDAP connection to perform
address book synchronization. The DC Directory credentials are passed
in the clear over the network and are vulnerable to being sniffed by
an attacker. If using the DC Directory internal LDAP server, the IP
Phone PAB Synchronizer client communicates to Cisco Unified
Communications Manager on TCP ports 8404 and 8405.

Cisco Unified Communications Manager 5.x, 6.x, 7.x
+-------------------------------------------------

Cisco Unified Communications Manager software versions 5.x, 6.x, and
7.x store user information as a part of the internal Cisco Unified
Communications Manager configuration database. The IP Phone PAB
Synchronizer client uses the AXL application programming interface
(API) to perform address book synchronization. After a client
successfully authenticates, the Cisco Unified Communications Manager
returns credentials for a database user account named TabSyncSysUser
that will be used by the client to synchronize an user's address
book. The TabSyncSysUser account has full read and write privileges
to the Cisco Unified Communications Manager configuration database.
Using the TabSyncSysUser credentials via the AXL API, an attacker can
modify any parameter in the database including creating new
administrator accounts.

Directory Service Integration
+----------------------------

Cisco Unified Communications Manager software versions 4.x, 5.x, 6.x,
and 7.x can be integrated with Microsoft Active Directory and several
non-Microsoft LDAP servers to perform user authentication. In order
to function properly, the integration process requires that
appropriate user credentials for the directory service are provided
to Cisco Unified Communications Manager. If an attacker intercepts or
sniffs the directory service credentials returned by a Cisco Unified
Communications Manager responding to an IP Phone PAB Synchronizer
client, the attacker may be able to leverage the credentials to gain
access to additional systems configured to use the directory service
for authentication.

Administrators should ensure that any directory service credentials
used for the Cisco Unified Communications Manager integration process
are configured to follow the principle of least privilege. The
credentials should be configured with only the privileges necessary
to access the directory service data needed for the integration
process to function properly. The use of overly privileged
administrator accounts is discouraged. Please see the Workarounds
section for more information on performing the integration of Cisco
Unified Communications Manager with AD using the least privilege
concept.

This vulnerability is documented in Cisco Bug IDs CSCso76587 and
CSCso78528 and has been assigned Common Vulnerabilities and Exposures
(CVE) identifier CVE-2009-0632.

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

CSCso76587 - Directory Manager password sent in clear from client

CVSS Base Score - 9

Access Vector           - Network
Access Complexity       - Low
Authentication          - Single
Confidentiality Impact  - Complete
Integrity Impact        - Complete
Availability Impact     - Complete

CVSS Temporal Score - 7.4

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

CSCso78528 - TabSyncSysUser (axl user) password sent in clear from client

CVSS Base Score - 9

Access Vector           - Network
Access Complexity       - Low
Authentication          - Single
Confidentiality Impact  - Complete
Integrity Impact        - Complete
Availability Impact     - Complete

CVSS Temporal Score - 7.4

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

Impact
======

Successful exploitation of this vulnerability may allow an attacker
to intercept user credentials that allow the attacker to escalate
their privilege level and obtain complete administrative access to a
vulnerable Cisco Unified Communications Manager system. If integrated
with an external directory service, the intercepted user credentials
may allow an attacker to gain access to additional systems configured
to use the directory service for authentication.

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 Manager software version 4.2(3)SR4b
contains the fix for this vulnerability. Administrators of Cisco
Unified CallManager software version 4.1 systems are encouraged to
upgrade to Cisco Unified Communications Manager software version 4.2
(3)SR4b in order to obtain fixed software. Version 4.2(3)SR4b can be
downloaded at the following link:

http://tools.cisco.com/support/downloads/go/PlatformList.x?sftType=Unified%20Communications%20Manager%20Updates&mdfid=280264388&treeName=Voice%20and%20Unified%20Communications&mdfLevel=Software%20Version/Option&url=null&modelName=Cisco%20Unified%20CallManager%20Version%204.2&isPlatform=N&treeMdfId=278875240&modifmdfid=null&imname=null&hybrid=Y&imst=N

Cisco Unified Communications Manager software version 4.3(2)SR1b
contains the fix for this vulnerability. Version 4.3(2)SR1b can be
downloaded at the following link:

http://tools.cisco.com/support/downloads/go/PlatformList.x?sftType=Unified%20Communications%20Manager%20Updates&mdfid=280771554&treeName=Voice%20and%20Unified%20Communications&mdfLevel=Software%20Version/Option&url=null&modelName=Cisco%20Unified%20Communications%20Manager%20Version%204.3&isPlatform=N&treeMdfId=278875240&modifmdfid=null&imname=null&hybrid=Y&imst=N

Cisco Unified Communications Manager software version 5.1(3e)
contains the fix for this vulnerability. Version 5.1(3e) can be
downloaded at the following link:

http://tools.cisco.com/support/downloads/go/ReleaseType.x?optPlat=null&isPlatform=Y&mdfid=280735907&sftType=Unified%20Communications%20Manager%20Updates&treeName=Voice%20and%20Unified%20Communications&modelName=Cisco%20Unified%20Communications%20Manager%20Version%205.1&mdfLevel=Software%20Version/Option&treeMdfId=278875240&modifmdfid=null&imname=null&hybrid=Y&imst=N

Cisco Unified Communications Manager software version 6.1(3) contains
the fix for this vulnerability. Version 6.1(3) can be downloaded at
the following link:

http://tools.cisco.com/support/downloads/go/PlatformList.x?sftType=Unified%20Communications%20Manager%20Updates&mdfid=281023410&treeName=Voice%20and%20Unified%20Communications&mdfLevel=Software%20Version/Option&url=null&modelName=Cisco%20Unified%20Communications%20Manager%20Version%206.1&isPlatform=N&treeMdfId=278875240&modifmdfid=null&imname=null&hybrid=Y&imst=N

Cisco Unified Communications Manager software version 7.0(2) contains
the fix for this vulnerability. Version 7.0(2) can be downloaded at
the following link:

http://tools.cisco.com/support/downloads/go/ReleaseType.x?optPlat=&isPlatform=Y&mdfid=281941895&sftType=Unified+Communications+Manager+Updates&treeName=Voice+and+Unified+Communications&modelName=Cisco+Unified+Communications+Manager+Version+7.0&mdfLevel=Software%20Version/Option&treeMdfId=278875240&modifmdfid=null&imname=&hybrid=Y&imst=N

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

It is possible to mitigate against this vulnerability using the
following workarounds.

Cisco Unified Communications Manager 4.x
+---------------------------------------

It is possible to mitigate this vulnerability by moving the ASP
script that IP Phone Personal Address Book (PAB) Scynchronizer
clients interact with to a directory location that is not accessible
to the Cisco Unified Communications Manager web server. The system
drive where the ASP script resides depends on how Cisco Unified
Communications Manager was installed. Employing this workaround will
prevent address book synchronization; however, the PAB application
will continue to function. The ASP script can be moved using the
following command:

    C:\> move c:\CiscoWebs\User\LDAPDetails.asp c:\temp

It is also possible to mitigate this vulnerability by implementing
filtering on screening devices or using the Windows firewall.
Administrators are advised to permit access to TCP ports 8404 and
8405 only from trusted networks.

Cisco Unified Communications Manager 5.x, 6.x, 7.x
+-------------------------------------------------

It is possible to mitigate this vulnerability by restricting the
permissions of the TabSyncSysUser database user account. In the Cisco
Unified Communications Manager Administration interface, navigate to 
User Management > Application User and search for the TabSyncSysUser
account. Remove all groups from the account and change the password.
Employing this workaround will prevent address book synchronization;
however, the PAB application will continue to function.

Active Directory Integration
+---------------------------

To improve the security of Cisco Unified Communications Manager
integration with Active Directory (AD), Cisco has produced a
whitepaper that provides a detailed explanation of how to perform
Cisco Unified Communications Manager integration with AD using the
least-privileged principle. The whitepaper can be downloaded here:

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080a83435.shtml

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-20090311-cucmpab.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/products/prod_warranties_item09186a008088e31f.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 vulnerability described in this advisory.

The vulnerability in Cisco Unified Communications Manager 4.x
software versions was reported to Cisco by Olivier Grosjeanne of
Dimension Data France. The vulnerability in Cisco Unified
Communications Manager 5.x, 6.x and 7.x software versions was
reported by Oliver Dewdney of LBI.

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-20090311-cucmpab.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      | 2009-March-11 | 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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