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

Wed Aug 25 10:40:00 EDT 2010

Cisco Unified Presence contains two denial of service (DoS)
vulnerabilities that affect the processing of Session Initiation
Protocol (SIP) messages. Exploitation of these vulnerabilities could
cause an interruption of presence services.

Cisco has released free software updates that address these
vulnerabilities. There are no workarounds for these vulnerabilities.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20100825-cup.shtml

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

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

The following products are affected:

  * Cisco Unified Presence 6.0 versions prior to 6.0(7)
  * Cisco Unified Presence 7.0 versions prior to 7.0(8)

Note: Cisco Unified Presence version 8.0(1) shipped with software
fixes for all the vulnerabilities described in this advisory.

Administrators of systems running Cisco Unified Presence can
determine the software version by viewing the main page of the Cisco
Unified Presence Administration interface. The software version can
be determined by running the command "show version active" using the
command line interface (CLI).

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

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

Details
=======

Cisco Unified Presence 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 presence 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
CSCtd14474 and has been assigned the CVE identifier CVE-2010-2839.
This vulnerability is fixed in Cisco Unified Presence versions 6.0(7)
and 7.0(8).

The second SIP DoS vulnerability is documented in Cisco bug ID
CSCtd39629 and has been assigned the CVE identifier CVE-2010-2840.
This vulnerability is fixed in Cisco Unified Presence versions 6.0(7)
and 7.0(8).

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

CSCtd14474 - SIPD Coredumps due to Possible Stack Corruption
During Fuzzing

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

CSCtd39629 - PE Coredump On Subscribe Message with Contact
Field Error

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 any of the vulnerabilities may result in
the interruption of presence services. Cisco Unified Presence will
restart the affected processes, but repeated attacks may result in a
sustained 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.

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     |  Recommended  |
|   Presence Version    |    Release    |
|-----------------------+---------------|
| 6.0                   | 6.0(7)        |
|-----------------------+---------------|
| 7.0                   | 7.0(8)        |
+---------------------------------------+

Cisco Unified Presence software can be downloaded at the following
link:

http://tools.cisco.com/support/downloads/go/Redirect.x?mdfid=280448682

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

There are no workarounds for the vulnerabilities described in this
advisory.

It is possible to mitigate these vulnerabilities by implementing
filtering on screening devices and permitting access to TCP ports
5060 and 5061 and to UDP ports 5060 and 5061 only from networks that
require SIP access to Cisco Unified Communications Manager servers.

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-20100825-cucm-cup.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.

All 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-20100825-cup.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-August-25 | 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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