Cisco Security Advisory: Cisco Unified Communications Manager Overflow Vulnerabilities
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Cisco Security Advisory: Cisco Unified Communications Manager
Overflow Vulnerabilities
Document ID: 92015
Advisory ID: cisco-sa-20070711-cucm
http://www.cisco.com/warp/public/707/cisco-sa-20070711-cucm.shtml
Revision 1.0
For Public Release 2007 July 11 1600 UTC (GMT)
- ---------------------------------------------------------------------
Contents
========
Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Version and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of this Notice: FINAL
Distribution
Revision History
Cisco Security Procedures
- ---------------------------------------------------------------------
Summary
=======
Cisco Unified Communications Manager (CUCM), formerly CallManager,
contains two overflow vulnerabilities that could allow a remote,
unauthenticated user to cause a denial of service (DoS) condition or
execute arbitrary code.
A workaround exists for one of the vulnerabilities.
Cisco has made free software available to address these
vulnerabilities for affected customers.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20070711-cucm.shtml
Affected Products
=================
Note: Cisco Unified CallManager versions 4.2, 4.3, 5.1 and 6.0 have
been renamed as Cisco Unified Communications Manager. CUCM versions
3.3, 4.0, 4.1 and 5.0 retain the Cisco Unified CallManager name.
Vulnerable Products
+------------------
These products are vulnerable:
* Cisco Unified CallManager 3.3 versions prior to 3.3(5)SR3
* Cisco Unified CallManager 4.1 versions prior to 4.1(3)SR5
* Cisco Unified CallManager 4.2 versions prior to 4.2(3)SR2
* Cisco Unified Communications Manager 4.3 versions prior to 4.3(1)
SR1
* Cisco Unified CallManager 5.0 and Communications Manager 5.1
versions prior to 5.1(2)
Administrators of systems running CUCM version 3.x and 4.x can
determine the software version by navigating to Help > About Cisco
Unified CallManager and selecting the Details button via the CUCM
Administration interface.
Administrators of systems running CUCM version 5.0 can determine the
software version by viewing the main page of the CUCM 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 version 6.0 and Cisco
CallManager Express are not affected by these vulnerabilities. No
other Cisco products are currently known to be affected by these
vulnerabilities.
Details
=======
Cisco Unified Communications Manager (CUCM), formerly CallManager, 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.
* CTL Provider Service Overflow
The Certificate Trust List (CTL) Provider service of CUCM
contains a heap overflow vulnerability that could allow a remote,
unauthenticated user to cause a DoS condition or execute
arbitrary code. The CTL Provider service listens on TCP port 2444
by default, but the port is user-configurable. This vulnerability
is corrected in CUCM versions 4.1(3)SR5, 4.2(3)SR2, 4.3(1)SR1 and
5.1(2). CUCM 3.x versions are not affected by this vulnerability.
This issue is documented in Cisco Bug ID CSCsi03042.
* RIS Data Collector Heap Overflow
The Real-Time Information Server (RIS) Data Collector service of
CUCM contains a heap overflow vulnerability that could allow a
remote, unauthenticated user to cause a DoS condition or execute
arbitrary code. The RIS Data Collector process listens on TCP
port 2556 by default, but the port is user-configurable. This
vulnerability is corrected in CUCM versions 3.3(5)SR2b, 4.1(3)
SR5, 4.2(3)SR2, 4.3(1)SR1 and 5.1(2). This issue is documented in
Cisco Bug ID CSCsi10509.
Vulnerability Scoring Details
=============================
Cisco is providing 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 1.0.
Cisco will provide a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of
the vulnerability in individual networks.
Cisco PSIRT will set the bias in all cases to normal. Customers are
encouraged to apply the bias parameter when determining the
environmental impact of a particular vulnerability.
CVSS is a standards based scoring method that conveys vulnerability
severity and helps determine urgency and priority of response.
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.
CSCsi03042 - CallManager CTL Provider Service Overflow
CVSS Base Score - 10
Access Vector - Remote
Access Complexity - Low
Authentication - Not Required
Confidentiality Impact - Complete
Integrity Impact - Complete
Availability Impact - Complete
Impact Bias - Normal
CVSS Temporal Score - 8.3
Exploitability - Functional
Remediation Level - Official-Fix
Report Confidence - Confirmed
CSCsi10509 - CallManager RIS Data Collector Heap Overflow
CVSS Base Score - 10
Access Vector - Remote
Access Complexity - Low
Authentication - Not Required
Confidentiality Impact - Complete
Integrity Impact - Complete
Availability Impact - Complete
Impact Bias - Normal
CVSS Temporal Score - 8.3
Exploitability - Functional
Remediation Level - Official-Fix
Report Confidence - Confirmed
Impact
======
Successful exploitation of these vulnerabilities may result in a DoS
condition or the execution of arbitrary code.
Software Version 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.
Workarounds
===========
It is possible to workaround the CTL Provider Service Overflow
vulnerability by disabling the CTL Provider Service if it is not
needed. Access to the CTL Provider Service is usually only required
during the initial configuration of CUCM authentication and
encryption features. For CUCM 4.x systems, please consult the
following documentation for details on how to disable CUCM services:
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008070ec49.html
For CUCM 5.x systems, please consult the following documentation for
details on how to disable CUCM services:
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008037ced2.html#wp1048220
Filtering traffic to affected CUCM systems on screening devices can
be used as a mitigation technique for both vulnerabilities:
* Permit access to TCP port 2444 only between the CUCM 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.
* Permit access to TCP port 2556 only from other CUCM cluster
systems to mitigate the RIS Data Collector overflow.
It is possible to change the default ports of the CTL Provider (2444/
TCP) and RIS Data Collector (2556/TCP) services. If changed,
filtering should be based on the values used. The values of the ports
can be viewed in CUCM Administration interface by following the
System > Service Parameters menu and selecting the appropriate
service.
There is currently no method to configure filtering directly on a
CUCM system.
Although it is often difficult to block traffic transiting your
network, it is possible to identify traffic that should never be
allowed to target your infrastructure devices and block that traffic
at the border of your network. Infrastructure ACLs are considered a
network security best practice and should be considered as a
long-term addition to good network security, as well as a workaround
for this specific vulnerability. The filters shown above should be
included as part of an infrastructure access list which will protect
all devices with IP addresses in the infrastructure IP address range.
The white paper entitled "Protecting Your Core: Infrastructure
Protection Access Control Lists" presents guidelines and recommended
deployment techniques for infrastructure protection access lists.
This document is available at the following link:
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml
Filters blocking access to TCP/2444 and TCP/2556 should be deployed
at the network edge as part of a transit access list which will
protect the router where the ACL is configured, as well as other
devices behind it. Further information about transit ACLs is
available in the white paper "Transit Access Control Lists: Filtering
at Your Edge," which is available at the following link:
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml
Additional mitigations that can be deployed on Cisco devices within
the network are available in the Cisco Applied Intelligence companion
document for this advisory:
http://www.cisco.com/warp/public/707/cisco-air-20070711-cucm.shtml
Obtaining Fixed Software
========================
Cisco will make free software available to address this vulnerability
for affected customers. This advisory will be updated as fixed
software becomes available. 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@xxxxxxxxx" or "security-alert@xxxxxxxxx"
for software upgrades.
Fixed software for CUCM can be obtained here:
CUCM 3.3 - First Fixed Release is CUCM 3.3(5)SR2b (Expected
Availability July 18), download link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-33?psrtdcat20e2
CUCM 4.0 - Upgrade to 4.1(3)SR5b or 4.2(3)SR@b
CUCM 4.1 - First Fixed Release is CUCM 4.1(3)SR5b, download link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-41?psrtdcat20e2
CUCM 4.2 - First Fixed Relesae is CUCM 4.2(3)SR2b, download link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-42?psrtdcat20e2
CUCM 4.3 - First Fixed Release is 4.3(1)SR1, download link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-43?psrtdcat20e2
CUCM 5.0 - Upgrade to CUCM 5.1(2a) *
CUCM 5.1 - First Fixed Release is CUCM 5.1(2a) *, download link:
http://www.cisco.com/pcgi-bin/tablebuild.pl/callmgr-51?psrtdcat20e2
* The vulnerabilities contained in this advisory were first fixed in
CUCM version 5.1(2). Users are encouraged to upgrade to CUCM 5.1(2a)
or later to obtain fixes for security vulnerabilities described in
Cisco security advisory:
http://www.cisco.com/warp/public/707/cisco-sa-20070711-cucm.shtml
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@xxxxxxxxx
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.
These vulnerabilities were reported to Cisco by the IBM Internet
Security Systems X-Force team.
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-20070711-cucm.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 | 2007-June-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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