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Cisco Security Advisory: Cisco Call Manager Denial of Service

Advisory ID: cisco-sa-20060118-ccmdos

http://www.cisco.com/warp/public/707/cisco-sa-20060118-ccmdos.shtml

Revision 1.0
============

For Public Release 2006 January 18 1600 UTC (GMT)

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Contents
========

    Summary
    Affected Products
    Details
    Impact
    Software Versions and Fixes
    Workarounds
    Obtaining Fixed Software
    Exploitation and Public Announcements
    Status of This Notice: FINAL
    Distribution
    Revision History
    Cisco Security Procedures

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Summary
=======

Cisco CallManager (CCM) is the software-based call-processing
component of the Cisco IP telephony solution which extends enterprise
telephony features and functions to packet telephony network devices
such as IP phones, media processing devices, voice-over-IP (VoIP)
gateways, and multimedia applications. All Cisco CallManager versions
are vulnerable to these Denial of Service (DoS) attacks, which may
result in services being interrupted or servers rebooting.

Cisco has made free software available to address this vulnerability
for affected customers. There are network-based workarounds available
to mitigate the effects of the vulnerability.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20060118-ccmdos.shtml.

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

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

  * Cisco CallManager 3.2 and earlier
  * Cisco CallManager 3.3, versions earlier than 3.3(5)SR1a
  * Cisco CallManager 4.0, versions earlier than 4.0(2a)SR2c
  * Cisco CallManager 4.1, versions earlier than 4.1(3)SR2

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

Details
=======

Vulnerable versions of Cisco Call Manager do not manage TCP
connections and Windows messages aggressively, leaving some
well-known, published ports vulnerable to Denial of Service attacks.

  * CSCea53907?CallManager does not time out TCP connections to port
    2000 aggressively enough, leading to a scenario where memory and
    CPU resources are consumed with enough open connections. In
    specific scenarios, CallManager will leave the TCP connection
    open indefinitely until either the Call Manager service is
    restarted or the server is rebooted.
  * CSCsa86197, CSCsb16635, CSCsb64161?Multiple connections to ports
    2001, 2002, or 7727 can fill up the Windows message queue. This
    prevents CCM from transacting with the Windows Service Manager,
    which restarts the CCM after a 30 second timeout.

Impact
======

Successful exploitation of these vulnerabilities may result in DoS
attacks, which may result in high CPU utilization, services being
interrupted, or servers rebooting. This may then lead to phones not
responding, phones unregistering from the Cisco CallManager, or Cisco
CallManager restarting..

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 CallManager software table (below) describes a
release train which will address all of the vulnerabilities mentioned
in this advisory. If a given release train is vulnerable, then the
earliest possible releases that contain the fixes (the "First Fixed
Release") and the anticipated date of availability for each are
listed in the "Engineering Special," "Service Release," and
"Maintenance Release" columns. A device running a Cisco CallManager
release in the given train that is earlier than the release in a
specific column (less than the First Fixed Release listed in the
Engineering Special or Special Release column) is known to be
vulnerable to one or more issues. The Cisco CallManager should be
upgraded at least to the indicated release or a later version
(greater than or equal to the First Fixed Release label).

+----------------------------------------------------------------------+
|    Version    |  Engineering  |    Service    | Maintenance Release  |
|               |    Special    |    Release    |                      |
|---------------+---------------+---------------+----------------------|
| 3.2 and       |               |               | migrate to 3.3 or    |
| earlier       |               |               | later                |
|---------------+---------------+---------------+----------------------|
| 3.3           | 3.3(5)ES24    | 3.3(5)SR1a    | no release planned   |
|---------------+---------------+---------------+----------------------|
| 4.0           | 4.0(2a)ES56   | 4.0(2a)SR2c   | no release planned   |
|---------------+---------------+---------------+----------------------|
| 4.1           | 4.1(2)ES50    | 4.1(3)SR2     | no release planned   |
|               | 4.1(3)ES24    |               |                      |
+----------------------------------------------------------------------+

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

While there are no workarounds available on the Cisco CallManager to
eliminate DoS attacks, securing the voice network with Cisco
CallManager security best practices may lessen the risk or mitigate
the effects of these vulnerabilities. By using access lists and rate
limiting to control access to the Cisco CallManager, the risk of
successful attack is greatly reduced. Cisco provides Solution
Reference Network Design (SRND) guides to help design and deploy
networking solutions, which can be found at 
http://www.cisco.com/warp/public/779/largeent/it/ese/srnd.html .

Obtaining Fixed Software
========================

Cisco has made free software available to address this vulnerability
for affected customers. 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/public/sw-license-agreement.html, or as otherwise 
set forth at Cisco.com Downloads at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "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 agreement 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 who do not hold a Cisco
service contract and customers who purchase through third-party
vendors but are unsuccessful at obtaining fixed software through
their point of sale should get their 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

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

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
for additional TAC contact information, including special 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 reported to Cisco by a customer.

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-20060118-ccmdos.

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-voip@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      | 2006-January-18 | 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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