Advisory ID: cisco-sa-20100922-cucmsip
For Public Release 2010 September 22 16:00 UTC (GMT)
Cisco Unified Communications Manager 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 voice services.
To address these vulnerabilities, Cisco has released free software
updates. There is a workaround for these vulnerabilities.
This advisory is posted at
Note: Cisco IOS® Software is also affected by
the vulnerabilities described in this advisory. A companion advisory for Cisco
IOS software is available at:
Note: The September 22, 2010, Cisco IOS Software Security Advisory bundled
publication includes six Cisco Security Advisories. Five of the advisories
address vulnerabilities in Cisco IOS Software and one advisory addresses
vulnerabilities in Cisco Unified Communications Manager. Each advisory lists
the releases that correct the vulnerability or vulnerabilities detailed in the
advisory. The table at the following URL lists releases that correct all Cisco
IOS Software vulnerabilities that have been published on September 22, 2010, or
Individual publication links are in "Cisco Event Response:
Semiannual Cisco IOS Software Security Advisory Bundled Publication" at the
The following products are affected by the vulnerabilities that are
described in this advisory:
Cisco Unified Communications Manager 6.x
Cisco Unified Communications Manager 7.x
Cisco Unified Communications Manager 8.x
Administrators of systems that are running Cisco Unified Communications
Manager versions 6.x, 7.x and 8.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
show version active command via the command-line
Cisco Unified Communications Manager version 4.x is not affected by
these vulnerabilities. No other Cisco products are currently known to be
affected by these vulnerabilities.
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.
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 and UDP ports 5060 and 5061) are affected.
The first SIP DoS vulnerability is documented in Cisco Bug ID
registered customers only)
and has been assigned the CVE identifier CVE-2010-2835. This vulnerability is
fixed in Cisco Unified Communications Manager versions 6.1(5), 7.0(2a)su3,
7.1(3b)su2, 7.1(5) and 8.0(1). The corresponding IOS defect is
The second SIP DoS vulnerability is documented in Cisco Bug ID
registered customers only)
and has been assigned the CVE identifier CVE-2010-2834. The second
vulnerability is fixed in Cisco Unified Communications Manager versions
6.1(5)SU1, 7.1(5) and 8.0(2). The corresponding IOS defect is
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:
Cisco has also provided a CVSS calculator to help compute
the environmental impact for individual networks at:
Successful exploitation of the vulnerabilities that are described in
this advisory could result in the interruption of voice services. Cisco Unified
Communications Manager will restart the affected processes, but repeated
attacks may result in a sustained DoS Condition.
When considering software upgrades, also consult
and any subsequent advisories to determine exposure and a complete upgrade
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
Cisco Unified Communication Manager Version
Note: The recommended releases listed in the table above are the latest
Cisco Unified Communications Manager versions available at the publication of
this advisory, and each release includes software fixes for all the
vulnerabilities described in this advisory.
Cisco Unified Communications Manager software can be downloaded at the
For customers who do not use SIP in their environment, there is a
workaround for these vulnerabilities. Cisco Unified Communication Manager
versions 6.1(4), 7.1(2) and 8.0(1) introduced the ability to disable SIP
processing. SIP processing is enabled by default. Use the following
instructions to disable SIP processing:
Step 1: Log into the Cisco Unified CM Administration
Step 2: Navigate to System > Service
Parameters and select the appropriate Cisco Unified Communications
Manager server and the "Cisco CallManager" service.
Step 3: Change the "SIP Interoperability Enabled"
parameter to False, and click Save.
Note: For a SIP processing change to take effect, the
Cisco CallManager Service must be restarted. For information on how to restart
the service, refer to the "Restarting the Cisco CallManager Service" section of
the document at:
It is possible to mitigate these vulnerabilities by implementing
filtering on screening devices and permitting access to TCP ports 5060 and 5061
and UDP ports 5060 and 5061 only from networks that require SIP access to Cisco
Unified Communications Manager servers.
Additional mitigations that can be deployed on Cisco devices in the
network are available in the companion document "Cisco Applied Mitigation
Bulletin: Identifying and Mitigating Exploitation of the Multiple
Vulnerabilities in Cisco Voice Products", which is available at the following
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
, or as otherwise set forth at Cisco.com Downloads at
Do not contact firstname.lastname@example.org or email@example.com
for software upgrades.
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
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 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)
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
for additional TAC contact information, including localized telephone numbers,
and instructions and e-mail addresses for use in various languages.
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.
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.
This advisory is posted on Cisco's worldwide website at :
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.
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.
Initial public release