AV:N/AC:M/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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Cisco Unified Communications Manager, formerly Cisco Unified CallManager, contains two denial of service (DoS) vulnerabilities in the Session Initiation Protocol (SIP) service. An exploit of these vulnerabilities may cause an interruption in voice services.
Cisco will release software updates that address these vulnerabilities and this advisory will be updated as fixed software becomes available. There are no workarounds for these vulnerabilities.
Note: Cisco IOS software is also affected by the vulnerabilities described in this advisory. A companion advisory for Cisco IOS software is available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080924-sip.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080924-cucm.
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The vulnerabilities described in this document apply to the Cisco Unified Communications Manager.
Vulnerable Products
The following Cisco Unified Communications Manager versions are affected:
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Cisco Unified CallManager 4.1 versions prior to 4.1.3SR8
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Cisco Unified CallManager 4.2 versions prior to 4.2(3)SR4b
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Cisco Unified CallManager 4.3 versions prior to 4.3(2)SR1a
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Cisco Unified Communications Manager 5.x versions prior to
5.1(3d)
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Cisco Unified Communications Manager 6.x versions prior to
6.1(2)su1
Administrators of systems running Cisco Unified CallManager 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.
In Cisco Unified CallManager version 4.x, the use of SIP as a call signaling protocol is not enabled by default, and for the Cisco Unified CallManager server to start listening for SIP messages on TCP and UDP ports 5060 and 5061 a SIP trunk needs to be configured.
In Cisco Unified Communications Manager versions 5.x and later, the use of SIP as a call signaling protocol is enabled by default in Cisco Unified Communications Manager and cannot be disabled.
Cisco IOS software is also affected by these vulnerabilities, although they are tracked by different Cisco bug IDs. A companion security advisory for Cisco IOS software is available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080924-sip.
Products Confirmed Not Vulnerable
With the exception of Cisco IOS software, no other Cisco products are currently known to be vulnerable to the issues described in this advisory.
Cisco Unified Communications Manager version 7.x is not affected by these vulnerabilities.
Cisco Unified CallManager version 4.x is not affected by these vulnerabilities if it does not have any SIP trunks configured.
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Cisco Unified CallManager 4.1 versions prior to 4.1.3SR8
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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 gateways, and multimedia applications.
SIP is a popular signaling protocol that is used to manage voice and video calls across IP networks such as the Internet. SIP is responsible for handling all aspects of call setup and termination. Voice and video are the most popular types of sessions that SIP handles, but the protocol is flexible to accommodate for other applications that require call setup and termination. SIP call signaling can use UDP (port 5060), TCP (port 5060), or TLS (TCP port 5061) as the underlying transport protocol.
Two DoS vulnerabilities exist in the SIP implementation of the Cisco Unified Communications Manager. These vulnerabilities can be triggered while processing specific and valid SIP messages and can lead to a reload of the main Cisco Unified Communications Manager process.
Version 4.x of Cisco Unified CallManager does not have SIP enabled by default unless a SIP trunk is configured. Versions 5.x and later of the Cisco Unified Communications Manager have SIP enabled by default and cannot be disabled.
The vulnerabilities are being tracked by the following Cisco bug IDs:
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CSCsu38644
(
registered customers only)
, assigned CVE ID CVE-2008-3800
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CSCsm46064
(
registered customers only)
, assigned CVE ID CVE-2008-3801
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CSCsu38644
(
registered customers only)
, assigned CVE ID CVE-2008-3800
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There are no workarounds for these vulnerabilities.
It is possible to mitigate the 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.
If the Cisco Unified Communications Manager does not need to provide SIP services, the ports on which the Cisco Unified Communications Manager listens for SIP messages can be moved to non-standard ports. To change the ports from their default values, log into the Cisco Unified CallManager Administration web interface, go to System > Cisco Unified CM, locate the appropriate Cisco Unified Communications Manager, change the fields SIP Phone Port and SIP Phone Secure Port to a non-standard port, then click Save. SIP Phone Port, by default 5060, refers to the TCP and UDP ports where the Cisco Unified Communications Manager listens for normal SIP messages, and SIP Phone Secure Port, by default 5061, refers to the TCP and UDP ports where the Cisco Unified Communications Manager listens for SIP over TLS messages. For additional information about this procedure, refer to the "Updating a Cisco Unified Communications Manager" section of the "Cisco Unified Communications Manager Administration Guide" at http://www.cisco.com/en/US/docs/voice_ip_comm/cucmbe/admin/7_0_1/ccmcfg/b02ccm.html#wp1057513.
Note: For a change of the SIP ports to take effect, the Cisco CallManager Service needs to be restarted. For information on how to accomplish this, refer to "Restarting the Cisco CallManager Service" at http://www.cisco.com/en/US/docs/voice_ip_comm/cucmbe/admin/7_0_1/ccmcfg/b03dpi.html#wp1075124.
Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory, which is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20080924-sip.
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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.
Major Release
First Fixed Release
Recommended Release
4.1.x
4.1(3)SR8
4.1(3)SR8a
4.2.x
4.2(3)SR4b
4.2(3)SR4b
4.3.x
4.3(2)SR1a
4.3(2)SR1b
5.1.x
5.1(3d)
5.1(3e)
6.1.x
6.1(2)SU1
6.1(3b)SU1
Downloading Cisco Unified Communications Manager Software
To download Cisco Unified Communications Manager Software go to the Voice Software Downloads section of the Software Center on cisco.com at https://sec.cloudapps.cisco.com/support/downloads/go/Redirect.x?mdfid=278875240, then navigate to IP Telephony > Call Control > Cisco Unified Communications Manager (CallManager) and select the appropriate version of Cisco Unified Communications Manager.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
These vulnerabilities were discovered by Cisco internal testing and during handling of customer service requests.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Revision 1.1
2009-April-09
Updated table of fixed software to indicate fixed software availability and current recommended releases. Changed advisory status from INTERIM to FINAL.
Revision 1.0
2008-September-24
Initial public release
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