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Cisco Security Advisory: Cisco Unified Communications Manager Denial
of Service Vulnerabilities
Advisory ID: cisco-sa-20080514-cucmdos
Revision 1.0
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Summary
=======
Cisco Unified Communications Manager, formerly Cisco CallManager,
contains multiple denial of service (DoS) vulnerabilities that may
cause an interruption in voice services, if exploited. These
vulnerabilities were discovered internally by Cisco. The following
Cisco Unified Communications Manager services are affected:
* Certificate Trust List (CTL) Provider
* Certificate Authority Proxy Function (CAPF)
* Session Initiation Protocol (SIP)
* Simple Network Management Protocol (SNMP) Trap
Cisco has released free software updates that address these
vulnerabilities. Workarounds that mitigate some of these
vulnerabilities are available.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20080514-cucmdos.shtml.
Affected Products
=================
Vulnerable Products
+------------------
These products are vulnerable:
* Cisco Unified CallManager 4.1 versions prior to 4.1.3SR7
* Cisco Unified Communications Manager 4.2 versions prior to 4.2(3)SR4
* Cisco Unified Communications Manager 4.3 versions prior to 4.3(2)
* Cisco Unified Communications Manager 5.x versions prior to 5.1(3)
* Cisco Unified Communications Manager 6.x versions prior to 6.1(1)
Administrators of systems running Cisco Unified Communications
Manager 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 versions 5.x and 6.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 these
vulnerabilities. No other Cisco products are currently known to be
affected by these vulnerabilities.
Details
=======
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, voice-over-IP (VoIP) gateways,
and multimedia applications.
Certificate Trust List Provider Related Vulnerabilities
The Certificate Trust List (CTL) Provider service of Cisco Unified
Communications Manager version 5.x contains a memory consumption
vulnerability that occurs when a series of malformed TCP packets are
received by a vulnerable Cisco Unified Communications Manager system
and may result in a DoS condition. The CTL Provider service listens
by default on TCP port 2444 and is user configurable. The CTL
Provider service is enabled by default. There is a workaround for
this vulnerability. The vulnerability is fixed in Cisco Unified
Communications Manager version 5.1(3). The vulnerability is
documented in Cisco Bug ID CSCsj80609 and has been assigned the
CVE identifier CVE-2008-1742.
The CTL Provider service of Cisco Unified Communications Manager
versions 5.x and 6.x contain a memory consumption vulnerability that
occurs when a series of malformed TCP packets are received by a
vulnerable Cisco Unified Communications Manager system and may result
in a DoS condition. The CTL Provider service listens by default on
TCP port 2444 and is user configurable. There is a workaround for
this vulnerability. The vulnerability is fixed in Cisco Unified
Communications Manager versions 5.1(3) and 6.1(1). This vulnerability
is documented in Cisco Bug ID CSCsi98433 and has been assigned the
CVE identifier CVE-2008-1743.
Certificate Authority Proxy Function Related Vulnerability
The Certificate Authority Proxy Function (CAPF) service of Cisco
Unified Communications Manager versions 4.1, 4.2 and 4.3 contain a
vulnerability when handling malformed input that may result in a DoS
condition. The CAPF service listens by default on TCP port 3804 and
is user configurable. The CAPF service is disabled by default. There
is a workaround for this vulnerability. This vulnerability is fixed
in Cisco Unified Communications Manager versions 4.1(3)SR7, 4.2(3)SR4
and 4.3(2). This vulnerability is documented in Cisco Bug ID
CSCsk46770 and has been assigned the CVE identifier CVE-2008-1744.
SIP-Related Vulnerabilities
Cisco Unified Communications Manager versions 5.x and 6.x contain a
vulnerability in the handling of malformed SIP JOIN messages that may
result in a DoS condition. SIP processing cannot be disabled in Cisco
Unified Communications Manager. There is no workaround for this
vulnerability. This vulnerability is fixed in Cisco Unified
Communications Manager versions 5.1(2) and 6.1(1). This vulnerability
is documented in Cisco Bug ID CSCsi48115 and has been assigned the
CVE identifier CVE-2008-1745.
Cisco Unified Communications Manager versions 4.1, 4.2, 4.3, 5.x and
6.x contain a vulnerability in the handling of SIP INVITE messages
that may result in a DoS condition. SIP processing cannot be disabled
in Cisco Unified Communications Manager. There is no workaround for
this vulnerability. The vulnerability is fixed in Cisco Unified
Communications Manager versions 4.1(3)SR6, 4.2(3)SR3, 4.3(2), 5.1(3)
and 6.1(1). This vulnerability is documented in Cisco Bug ID
CSCsk46944 and has been assigned the CVE identifier CVE-2008-1747.
Cisco Unified Communications Manager versions 4.1, 4.2, 4.3, 5.x and
6.x contain a vulnerability in the handling of SIP INVITE messages
that may result in a DoS condition. SIP processing cannot be disabled
in Cisco Unified Communications Manager. There is no workaround for
this vulnerability. This vulnerability is fixed in Cisco Unified
Communications Manager versions 4.1(3)SR7, 4.2(3)SR4, 4.3(2), 5.1(3)
and 6.1(1). This vulnerability is documented in Cisco Bug ID
CSCsl22355 and has been assigned the CVE identifier CVE-2008-1748.
SNMP Trap-Related Vulnerability
The SNMP Trap Agent service of Cisco Unified Communications Manager
versions 4.1, 4.2, 4.3, 5.x and 6.x contain a vulnerability that
occurs when a series of malformed UDP packets are received by a
vulnerable Cisco Unified Communications Manager system and may result
in a DoS condition. The SNMP Trap Agent service listens by default on
UDP port 61441. There is a workaround for this vulnerability. This
vulnerability is fixed in Cisco Unified Communications Manager
versions 4.1(3)SR6, 4.2(3)SR3, 4.3(2), 5.1(3) and 6.1(1). This
vulnerability is documented in Cisco Bug ID CSCsj24113 and has been
assigned the CVE identifier CVE-2008-1746.
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
* CSCsj80609 - Memory Leak Due to TCPFUZZ on Port 2444 (CTLProvider)
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
* CSCsi98433 - CTLProvider leaks memory in certain scenarios
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
* CSCsk46770 - CAPF crash with network traffic
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
* CSCsi48115 - CM 6.1 stops providing service when receiving malformed Join sip-header
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
* CSCsk46944 - CCM service restarts on receiving a valid SIP Packet
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
* CSCsl22355 - CCM does not validate SIP URL input properly
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
* CSCsj24113 - CCM Process Coredump/Restart During ISIC Execution Against Port 61441
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 the vulnerabilities in this advisory may
result in the interruption of voice services.
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 CallManager version 4.1(3)SR7 contains fixes for all
vulnerabilities affecting Cisco Unified CallManager version 4.1
listed in this advisory. It can downloaded at the following link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-41?psrtdcat20e2
Cisco Unified Communications Manager version 4.2(3)SR4 contains fixes
for all vulnerabilities affecting Cisco Unified Communications
Manager version 4.2 listed in this advisory and is scheduled to be
released in early June, 2008. It will be available for download at
the following link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-42?psrtdcat20e2
Cisco Unified Communications Manager version 4.3(2) contains fixes
for all vulnerabilities affecting Cisco Unified Communications
Manager version 4.2 listed in this advisory. It can downloaded at the
following link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-43?psrtdcat20e2
Cisco Unified Communications Manager version 5.1(3) contains fixes
for all vulnerabilities affecting Cisco Unified Communications
Manager version 5.x listed in this advisory. It can downloaded at the
following link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-51?psrtdcat20e2
Cisco Unified Communications Manager version 6.1(1) contains fixes
for all vulnerabilities affecting Cisco Unified Communications
Manager version 6.x listed in this advisory. It can downloaded at the
following link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-61?psrtdcat20e2
Workarounds
===========
CTL Provider Related Vulnerabilities
To mitigate against the CTL Provider service vulnerabilities
(CSCsj80609 and CSCsi98433), system administrators can disable the
CTL Provider service if it is not needed. Access to the CTL Provider
Service is usually only required during the initial configuration of
Cisco Unified Communications Manager authentication and encryption
features. The CTL Provider service is controlled via the Cisco CTL
Provider menu selection.
It is possible to mitigate the CTL Provider vulnerabilities by
implementing filtering on screening devices. If the CTL Provider
service is enabled, permit access to TCP port 2444 only between the
Cisco Unified Communications Manager systems where the CTL Provider
service is active and the CTL Client, usually on the administrator's
workstation, to mitigate the CTL Provider service overflow.
Note: It is possible to change the default port of the CTL Provider
service (TCP port 2444). If changed, filtering should be based on the
values used. The values of the ports can be viewed in Cisco Unified
Communications Manager Administration interface by following the
System > Service Parameters menu and selecting the appropriate
service.
CAPF Related Vulnerability
To mitigate against the CAPF service vulnerability (CSCsk46770),
system administrators can disable the CAPF service if it is not
needed. Access to the CAPF service is only required if Cisco Unified
Communications Manager systems and IP phone devices are configured to
use certificates for a secure deployment. If phones are not
configured to use certificates, then the CAPF service can be
disabled. The CAPF service is controlled by the Cisco Certificate
Authority Proxy Function menu selection.
It is possible to mitigate the CAPF vulnerability by implementing
filtering on screening devices. If the CAPF service is enabled,
permit access to TCP port 3804 only from networks that contain IP
phone devices needing to utilize the CAPF service.
SIP-Related Vulnerabilities
It is possible to mitigate the SIP vulnerabilities by implementing
filtering on screening devices. Permit TCP/UDP access to ports 5060
and 5061 from only networks that need SIP access to Cisco Unified
Communications Manager servers.
SNMP Trap-Related Vulnerability
To mitigate against the SNMP Trap service vulnerability (CSCsj24113),
system administrators can disable the SNMP Trap service. For Cisco
Unified Communications Manager 4.x systems, the SNMP Trap service is
controlled by the embedded Windows SNMP sevice. To disable the
Windows SNMP service, navigate to Start > Programs > Administrative
Tools > Services, and stop the SNMP Service.
Note: The SNMP Trap Service listed in the Windows Service
configuration screen is not applicable to this vulnerability and
disabling it does not provide any benefit as a workaround for this
vulnerability. For Cisco Unified Communications Manager 5.x and 6.x
systems, the SNMP Trap service is controlled via the Cisco
CallManager SNMP Service selection on the Control Center Feature
Services screen.
It is possible to mitigate the SNMP Trap service vulnerability by
implementing filtering on screening devices. Permit access to UDP
port 61441 only from management systems that need access to the SNMP
Trap service.
For Cisco Unified Communications Manager 4.x systems, please consult
the following documentation for details on how to disable Cisco
Unified Communications Manager services:
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008070ec49.html
For Cisco Unified Communications Manager 5.x and 6.x systems, please
consult the following documentation for details on how to disable
Cisco Unified Communications Manager services:
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008037ced2.html#wp1048220
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-20080514-cucmdos.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.
ustomers 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@xxxxxxxxx or security-alert@xxxxxxxxx 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@xxxxxxxxx
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/warp/public/687/Directory/DirTAC.shtml
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.
These vulnerabilities were discovered internally 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-20080514-cucmdos.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@xxxxxxxxx
* first-teams@xxxxxxxxx
* bugtraq@xxxxxxxxxxxxxxxxx
* vulnwatch@xxxxxxxxxxxxx
* cisco@xxxxxxxxxxxxxxxxx
* cisco-nsp@xxxxxxxxxxxxxxx
* full-disclosure@xxxxxxxxxxxxxxxxx
* comp.dcom.sys.cisco@xxxxxxxxxxxxxxxxxx
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 | 2008-May-14 | 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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