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Cisco Security Advisory

Cisco IOS Software Session Initiation Protocol Denial of Service Vulnerability

Advisory ID: cisco-sa-20120926-sip

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-sip

Revision 1.1

Last Updated  2012 October 3 17:48  UTC (GMT)

For Public Release 2012 September 26 16:00  UTC (GMT)


Summary

A vulnerability exists in the Session Initiation Protocol (SIP) implementation in Cisco IOS Software and Cisco IOS XE Software that could allow an unauthenticated, remote attacker to cause an affected device to reload. Affected devices must be configured to process SIP messages and for pass-through of Session Description Protocol (SDP) for this vulnerability to be exploitable.

Cisco has released free software updates that address this vulnerability. There are no workarounds for devices that must run SIP; however, mitigations are available to limit exposure to the vulnerability.

This advisory is available at the following link:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-sip

Note: The September 26, 2012, Cisco IOS Software Security Advisory bundled publication includes nine Cisco Security Advisories. Eight of the advisories address vulnerabilities in Cisco IOS Software, and one advisory addresses a vulnerability in Cisco Unified Communications Manager. Each Cisco IOS Software Security Advisory lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as well as the Cisco IOS Software releases that correct all Cisco IOS Software vulnerabilities in the September 2012 bundled publication. 

Individual publication links are in "Cisco Event Response: Semi-Annual Cisco IOS Software Security Advisory Bundled Publication" at the following link:

http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep12.html


Cisco Unified Communications Manager is affected by the vulnerability described in this advisory. A separate Cisco Security Advisory has been published to disclose the vulnerability that affects the Cisco Unified Communications Manager at the following location:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-cucm

Affected Products


Vulnerable Products

Cisco devices that are running affected Cisco IOS Software or Cisco IOS XE Software versions are vulnerable when they are configured to process SIP messages and when pass-through of Session Description Protocol (SDP) is enabled.

Recent versions of Cisco IOS Software do not process SIP messages by default. Creating a dial peer by issuing the dial-peer voice configuration command will start the SIP processes, causing the Cisco IOS device to process SIP messages. In addition, several features within Cisco Unified Communications Manager Express, such as ePhones, will also automatically start the SIP process when they are configured, causing the device to start processing SIP messages. The following is an example of an affected configuration:

dial-peer voice <Voice dial-peer tag> voip
 ...
!

In addition to inspecting the Cisco IOS device configuration for a dial-peer command that causes the device to process SIP messages, administrators can also use the show processes | include SIP command to determine whether Cisco IOS Software is running the processes that handle SIP messages. In the following example, the presence of the processes CCSIP_UDP_SOCKET or CCSIP_TCP_SOCKET indicates that the Cisco IOS device will process SIP messages:

Router# show processes | include SIP
 149 Mwe 40F48254            4          1    400023108/24000  0 CCSIP_UDP_SOCKET
 150 Mwe 40F48034            4          1    400023388/24000  0 CCSIP_TCP_SOCKET

Note: Because there are several ways a device running Cisco IOS Software can start processing SIP messages, it is recommended that the show processes | include SIP command be used to determine whether the device is processing SIP messages instead of relying on the presence of specific configuration commands.

A device is only affected when SIP is enabled and when SDP pass-through is enabled at the global level or dial-peer level. At the global level, SDP pass-through is configured as follows:

voice service voip
 sip
pass-thru content sdp
At the dial-peer level, SDP pass-through is configured as follows:
dial-peer voice <peer ID> voip
voice-class sip pass-thru content sdp
Cisco Unified Border Element (Enterprise) images are also affected by this vulnerability.

Note: The Cisco Unified Border Element feature (CUBE), previously known as the Cisco Multiservice IP-to-IP Gateway, is a special Cisco IOS Software image that runs on Cisco multiservice gateway platforms. It provides a network-to-network interface point for billing, security, call admission control, quality of service, and signaling interworking.

To determine the Cisco IOS Software release that is running on a Cisco product, administrators can log in to the device and issue the show version command to display the system banner. The system banner confirms that the device is running Cisco IOS Software by displaying text similar to "Cisco Internetwork Operating System Software" or "Cisco IOS Software." The image name displays in parentheses, followed by "Version" and the Cisco IOS Software release name. Other Cisco devices do not have the show version command or may provide different output.

The following example identifies a Cisco product that is running Cisco IOS Software Release 15.0(1)M1 with an installed image name of C3900-UNIVERSALK9-M:

Router> show version 
Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.0(1)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Wed 02-Dec-09 17:17 by prod_rel_team
!--- output truncated 

Additional information about Cisco IOS Software release naming conventions is available in "White Paper: Cisco IOS and NX-OS Software Reference Guide" at http://www.cisco.com/web/about/security/intelligence/ios-ref.html.



Cisco IOS XE Software is affected by this vulnerability.

Note: Cisco Unified Communications Manager is affected by the vulnerability described in this advisory. A separate Cisco Security Advisory has been published to disclose the vulnerability that affects the Cisco Unified Communications Manager at the following location:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-cucm

Products Confirmed Not Vulnerable

The SIP Application Layer Gateway (ALG), which is used by the Cisco IOS Network Address Translation (NAT) and firewall features of Cisco IOS Software, is not affected by this vulnerability.

Cisco Unified Border Element (SP Edition) is not affected by this vulnerability.

Cisco IOS XR Software is not affected by this vulnerability.

No other Cisco products are currently known to be affected by this vulnerability.

Details

Session Initiation Protocol (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 has the flexibility to accommodate other applications that require call setup and termination. SIP call signaling can use UDP (port 5060), TCP (port 5060), or Transport Layer Security (TLS; TCP port 5061) as the underlying transport protocol.

A vulnerability exists in the SIP implementation in Cisco IOS Software and Cisco IOS XE Software that could allow a remote attacker to cause an affected device to reload. This vulnerability is triggered when an affected device processes a crafted SIP message that contains a valid Session Description Protocol (SDP) message. Only traffic destined to the device can trigger the vulnerability; transit SIP traffic is not an exploit vector. SDP pass-through must be enabled, either at the global level, or at the dial-peer level, for a device to be affected by this vulnerability.

Note: In cases where SIP is running over TCP transport, a TCP three-way handshake is necessary to exploit this vulnerability.

This vulnerability is documented in Cisco bug IDs CSCtj33003 (registered customers only) and CSCtw84664 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-3949.

Note: This vulnerability also affects Cisco Unified Communications Manager. The corresponding Cisco bug ID is CSCtw66721 (registered customers only). Refer to the separate Cisco Security Advisory for the Cisco Unified Communications Manager for additional details.

Vulnerability Scoring Details

Cisco has scored the vulnerability in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this security advisory is in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps organizations determine the urgency and priority of a response.

Cisco has provided a base and temporal score. Customers can also compute environmental scores that help determine the impact of the vulnerability in their own networks.

Cisco has provided additional information regarding CVSS at the following link:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to compute the environmental impact for individual networks at the following link:

http://intellishield.cisco.com/security/alertmanager/cvss


CSCtj33003 and CSCtw84664 ("CUBE: Crafted SDP message may cause crash or interoperability issue" and "Crafted SDP message may cause crash".)

Calculate the environmental score of CSCtj33003 and CSCtw84664

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed


Impact

Successful exploitation of the vulnerability could cause an affected device to reload. Repeated exploitation could result in a sustained denial of service (DoS) condition.

Software Versions and Fixes

When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.

In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

Cisco IOS Software

Each row of the following Cisco IOS Software table corresponds to a Cisco IOS Software train. If a particular train is vulnerable, the earliest releases that contain the fix are listed in the First Fixed Release column. The First Fixed Release for All Advisories in the September 2012 Bundled Publication column lists the earliest possible releases that correct all the published vulnerabilities in the Cisco IOS Software Security Advisory bundled publication. Cisco recommends upgrading to the latest available release, where possible.

The Cisco IOS Software Checker allows customers to search for Cisco Security Advisories that address specific Cisco IOS Software releases. This tool is available on the Cisco Security Intelligence Operations (SIO) portal at http://tools.cisco.com/security/center/selectIOSVersion.x

Major Release      Availability of Repaired Releases
Affected 12.0-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
There are no affected 12.0 based releases
Affected 12.2-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
12.2 Not vulnerable
Not vulnerable
12.2B Vulnerable; First fixed in Release 12.4
Releases up to and including 12.2(4)B8 are not vulnerable.
Vulnerable; First fixed in Release 12.4
Releases up to and including 12.2(4)B8 are not vulnerable.
12.2BC Not vulnerable
Not vulnerable
12.2BW Not vulnerable
Not vulnerable
12.2BX Vulnerable; migrate to any release in 12.2SB
Releases up to and including 12.2(15)BX are not vulnerable.
12.2(15)BX
Releases up to and including 12.2(2)BX1 are not vulnerable.
12.2BY Not vulnerable
Not vulnerable
12.2BZ Not vulnerable
Not vulnerable
12.2CX Not vulnerable
Not vulnerable
12.2CY Not vulnerable
Not vulnerable
12.2CZ Vulnerable; migrate to any release in 12.2S
Vulnerable; migrate to any release in 12.2S
12.2DA Not vulnerable
Not vulnerable
12.2DD Not vulnerable
Not vulnerable
12.2DX Not vulnerable
Not vulnerable
12.2EU Not vulnerable
Not vulnerable
12.2EW Not vulnerable
Not vulnerable
12.2EWA Not vulnerable
Not vulnerable
12.2EX Not vulnerable
Vulnerable; First fixed in Release 15.0SE
Releases up to and including 12.2(37)EX are not vulnerable.
12.2EY Not vulnerable
Vulnerable; First fixed in Release 15.1EY
Releases up to and including 12.2(46)EY are not vulnerable.
12.2EZ Not vulnerable
Not vulnerable
12.2FX Not vulnerable
Not vulnerable
12.2FY Not vulnerable
Not vulnerable
12.2FZ Not vulnerable
Not vulnerable
12.2IRA Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRB Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRC Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRD Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRE Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRF Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IRH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IRI Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IXA Not vulnerable
Not vulnerable
12.2IXB Not vulnerable
Not vulnerable
12.2IXC Not vulnerable
Not vulnerable
12.2IXD Not vulnerable
Not vulnerable
12.2IXE Not vulnerable
Not vulnerable
12.2IXF Not vulnerable
Not vulnerable
12.2IXG Not vulnerable
Not vulnerable
12.2IXH Not vulnerable
Not vulnerable
12.2JA Not vulnerable
Not vulnerable
12.2JK Not vulnerable
Not vulnerable
12.2MB Not vulnerable
Not vulnerable
12.2MC Releases up to and including 12.2(15)MC1 are not vulnerable.
Releases 12.2(15)MC2b and later are not vulnerable. First fixed in Release 12.4
Releases up to and including 12.2(15)MC1 are not vulnerable. Releases 12.2(15)MC2b and later are not vulnerable. First fixed in Release 12.4
12.2MRA Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2MRB Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2S Not vulnerable
Not vulnerable
12.2SB Not vulnerable
12.2(33)SB13
12.2SBC Not vulnerable
Vulnerable; First fixed in Release 12.2SB
12.2SCA Not vulnerable
Vulnerable; First fixed in Release 12.2SCF
12.2SCB Not vulnerable
Vulnerable; First fixed in Release 12.2SCF
12.2SCC Not vulnerable
Vulnerable; First fixed in Release 12.2SCF
12.2SCD Not vulnerable
Vulnerable; First fixed in Release 12.2SCF
12.2SCE Not vulnerable
Vulnerable; First fixed in Release 12.2SCF
12.2SCF Not vulnerable
12.2(33)SCF4
12.2SCG Not vulnerable
Not vulnerable
12.2SE Not vulnerable
12.2(46)SE1
12.2(55)SE6
12.2SEA Not vulnerable
Not vulnerable
12.2SEB Not vulnerable
Not vulnerable
12.2SEC Not vulnerable
Not vulnerable
12.2SED Not vulnerable
Not vulnerable
12.2SEE Not vulnerable
Not vulnerable
12.2SEF Not vulnerable
Not vulnerable
12.2SEG Not vulnerable
Not vulnerable
12.2SG Not vulnerable
12.2(53)SG8
Vulnerable; releases up to and including 12.2(46)SG1 are not vulnerable.
12.2SGA Not vulnerable
Not vulnerable
12.2SM Not vulnerable
Not vulnerable
12.2SO Not vulnerable
Not vulnerable
12.2SQ Not vulnerable
Releases up to and including 12.2(44)SQ2 are not vulnerable.
12.2SRA Not vulnerable
Not vulnerable
12.2SRB Not vulnerable
Not vulnerable
12.2SRC Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2SRD Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2SRE Not vulnerable
12.2(33)SRE7
12.2STE Not vulnerable
Not vulnerable
12.2SU Not vulnerable
Not vulnerable
12.2SV Not vulnerable
Not vulnerable
12.2SVA Not vulnerable
Not vulnerable
12.2SVC Not vulnerable
Not vulnerable
12.2SVD Not vulnerable
Not vulnerable
12.2SVE Not vulnerable
Not vulnerable
12.2SW Not vulnerable
Not vulnerable
12.2SX Not vulnerable
Not vulnerable
12.2SXA Not vulnerable
Not vulnerable
12.2SXB Not vulnerable
Not vulnerable
12.2SXD Not vulnerable
Not vulnerable
12.2SXE Not vulnerable
Not vulnerable
12.2SXF Not vulnerable
Not vulnerable
12.2SXH Not vulnerable

Vulnerable; releases up to and including 12.2(33)SXH7 are not vulnerable
12.2SXI Not vulnerable
12.2(33)SXI10
12.2SXJ Not vulnerable
12.2(33)SXJ4
12.2SY Not vulnerable
12.2(50)SY3
12.2SZ Not vulnerable
Not vulnerable
12.2T Vulnerable; First fixed in Release 12.4
Releases up to and including 12.2(8)T10 are not vulnerable.
Vulnerable; First fixed in Release 12.4
Releases up to and including 12.2(8)T10 are not vulnerable.
12.2TPC Not vulnerable
Not vulnerable
12.2WO Not vulnerable
Vulnerable; First fixed in Release 15.0SG
12.2XA Not vulnerable
Not vulnerable
12.2XB Not vulnerable
Not vulnerable
12.2XC Not vulnerable
Not vulnerable
12.2XD Not vulnerable
Not vulnerable
12.2XE Not vulnerable
Not vulnerable
12.2XF Not vulnerable
Not vulnerable
12.2XG Not vulnerable
Not vulnerable
12.2XH Not vulnerable
Not vulnerable
12.2XI Not vulnerable
Not vulnerable
12.2XJ Not vulnerable
Not vulnerable
12.2XK Not vulnerable
Not vulnerable
12.2XL Not vulnerable
Not vulnerable
12.2XM Not vulnerable
Not vulnerable
12.2XNA Please see Cisco IOS-XE Software Availability
Please see Cisco IOS-XE Software Availability
12.2XNB Please see Cisco IOS-XE Software Availability
Please see Cisco IOS-XE Software Availability
12.2XNC Please see Cisco IOS-XE Software Availability
Please see Cisco IOS-XE Software Availability
12.2XND Please see Cisco IOS-XE Software Availability
Please see Cisco IOS-XE Software Availability
12.2XNE Please see Cisco IOS-XE Software Availability
Please see Cisco IOS-XE Software Availability
12.2XNF Please see Cisco IOS-XE Software Availability
Please see Cisco IOS-XE Software Availability
12.2XO Not vulnerable
Vulnerable; First fixed in Release 12.2SG
Releases up to and including 12.2(40)XO are not vulnerable.
12.2XQ Not vulnerable
Not vulnerable
12.2XR Not vulnerable
Not vulnerable
12.2XS Not vulnerable
Not vulnerable
12.2XT Not vulnerable
Not vulnerable
12.2XU Not vulnerable
Not vulnerable
12.2XV Not vulnerable
Not vulnerable
12.2XW Not vulnerable
Not vulnerable
12.2YA Not vulnerable
Not vulnerable
12.2YC Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2YD Not vulnerable
Not vulnerable
12.2YE Not vulnerable
Not vulnerable
12.2YK Not vulnerable
Not vulnerable
12.2YO Not vulnerable
Not vulnerable
12.2YP Not vulnerable
Not vulnerable
12.2YT Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2YW Not vulnerable
Not vulnerable
12.2YX Not vulnerable
Not vulnerable
12.2YY Not vulnerable
Not vulnerable
12.2YZ Not vulnerable
Not vulnerable
12.2ZA Not vulnerable
Not vulnerable
12.2ZB Not vulnerable
Not vulnerable
12.2ZC Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2ZD Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2ZE Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.2ZH Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.2ZJ Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2ZP Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2ZU Not vulnerable
Not vulnerable
12.2ZX Not vulnerable
Vulnerable; First fixed in Release 12.2SB
12.2ZY Not vulnerable
Not vulnerable
12.2ZYA Not vulnerable
Not vulnerable
Affected 12.3-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
12.3 Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3B Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3BC Not vulnerable
Not vulnerable
12.3BW Not vulnerable
Not vulnerable
12.3JA Not vulnerable

Not vulnerable
12.3JEA Not vulnerable
Not vulnerable
12.3JEB Not vulnerable
Not vulnerable
12.3JEC Not vulnerable
Not vulnerable
12.3JED Not vulnerable
Not vulnerable
12.3JEE Not vulnerable
Not vulnerable
12.3JK Releases up to and including 12.3(2)JK3 are not vulnerable.
Releases 12.3(8)JK1 and later are not vulnerable. First fixed in Release 12.4
Releases up to and including 12.3(2)JK3 are not vulnerable. Releases 12.3(8)JK1 and later are not vulnerable. First fixed in Release 12.4
12.3JL Not vulnerable
Not vulnerable
12.3JX Not vulnerable
Not vulnerable
12.3T Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3TPC Releases up to and including 12.3(4)TPC11a are not vulnerable.
Releases up to and including 12.3(4)TPC11a are not vulnerable.
12.3VA Not vulnerable
Not vulnerable
12.3XA Releases prior to 12.3(2)XA7 are vulnerable; Releases 12.3(2)XA7 and later are not vulnerable. First fixed in Release 12.4
Releases prior to 12.3(2)XA7 are vulnerable; Releases 12.3(2)XA7 and later are not vulnerable. First fixed in Release 12.4
12.3XB Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3XC Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XD Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XE Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XF Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3XG Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XI Vulnerable; migrate to any release in 12.2SB
12.3(7)XI1b
12.3XJ Vulnerable; migrate to any release in 12.4XN
Vulnerable; First fixed in Release 12.4T
12.3XK Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XL Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3XQ Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XR Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XU Vulnerable; First fixed in Release 12.4T
Releases up to and including 12.3(8)XU1 are not vulnerable.
Vulnerable; First fixed in Release 12.4T
Releases up to and including 12.3(8)XU1 are not vulnerable.
12.3XW Vulnerable; migrate to any release in 12.4XN
Vulnerable; First fixed in Release 12.4T
12.3XX Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XY Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3XZ Vulnerable; First fixed in Release 12.4
Vulnerable; First fixed in Release 12.4
12.3YD Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YF Vulnerable; migrate to any release in 12.4XN
Vulnerable; First fixed in Release 12.4T
12.3YG Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3YI Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YJ Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YK Releases prior to 12.3(11)YK3 are vulnerable; Releases 12.3(11)YK3 and later are not vulnerable. First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3YM Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3YQ Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3YS Vulnerable; First fixed in Release 12.4T
Releases up to and including 12.3(11)YS1 are not vulnerable.
Vulnerable; First fixed in Release 12.4T
12.3YT Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3YU Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.3YX Vulnerable; migrate to any release in 12.4XN
Vulnerable; First fixed in Release 12.4T
12.3YZ Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3ZA Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
Affected 12.4-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
12.4 12.4(25g)
12.4(25g)
12.4GC Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JA Not vulnerable
Not vulnerable
12.4JAL Not vulnerable
Not vulnerable
12.4JAX Not vulnerable
Not vulnerable
12.4JAY Not vulnerable
Not vulnerable
12.4JDA Not vulnerable
Not vulnerable
12.4JDC Not vulnerable
Not vulnerable
12.4JDD Not vulnerable
Not vulnerable
12.4JDE Not vulnerable
Not vulnerable
12.4JHA Not vulnerable
Not vulnerable
12.4JHB Not vulnerable
Not vulnerable
12.4JHC Not vulnerable
Not vulnerable
12.4JK Not vulnerable
Not vulnerable
12.4JL Not vulnerable
Not vulnerable
12.4JX Not vulnerable
Not vulnerable
12.4JY Not vulnerable
Not vulnerable
12.4JZ Not vulnerable
Not vulnerable
12.4MD Not vulnerable
12.4(24)MD7
12.4MDA Not vulnerable

Releases up to and including 12.4(22)MDA6 are not vulnerable
12.4MDB Not vulnerable
12.4(24)MDB10
12.4MR Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRA Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRB Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4SW Not vulnerable
Not vulnerable
12.4T 12.4(15)T17
12.4(24)T7
12.4(24)T8
12.4XA Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XB Releases prior to 12.4(2)XB12 are vulnerable; Releases 12.4(2)XB12 and later are not vulnerable. First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XC Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XD Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XE Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XF Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XG Releases up to and including 12.4(9)XG1 are not vulnerable.
Releases 12.4(9)XG3 and later are not vulnerable. First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XJ Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XK Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XL Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XM Releases up to and including 12.4(15)XM are not vulnerable.
Releases 12.4(15)XM3 and later are not vulnerable. First fixed in Release 12.4T
Releases up to and including 12.4(15)XM are not vulnerable. Releases 12.4(15)XM3 and later are not vulnerable. First fixed in Release 12.4T
12.4XN Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XP Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XQ Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XR Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XT Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XV Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XW Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XY Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XZ Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4YA Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4YB Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4YD Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4YE Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4YG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Affected 15.0-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
15.0EX Not vulnerable
Not vulnerable
15.0EY Not vulnerable
Not vulnerable
15.0M 15.0(1)M9
15.0(1)M9
15.0MR Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.0MRA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.0S Not vulnerable

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0(1)S6

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SE Not vulnerable

15.0(2)SE
15.0SG Not vulnerable

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0(2)SG5
15.0(2)SG6; Available on 11-OCT-12

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SY Not vulnerable
15.0(1)SY2
15.0XA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.0XO Cisco IOS XE devices: Please see Cisco IOS-XE Software Availability

Cisco IOS XE devices: Please see Cisco IOS-XE Software Availability
Affected 15.1-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
15.1EY Not vulnerable
15.1(2)EY4
15.1GC Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.1M 15.1(4)M5
15.1(4)M5
15.1MR Not vulnerable
15.1(3)MR; Available on 01-OCT-12
15.1S Not vulnerable

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

15.1(3)S
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1SG Not vulnerable

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1(1)SG1

15.1(2)SG 12-NOV-12
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1SNG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SNH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SNI Not vulnerable
Vulnerable; migrate to any release in 15.2SNG
15.1SV Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1T Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.1XB Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
Affected 15.2-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
15.2GC Releases prior to 15.2(3)GC are vulnerable; Releases 15.2(3)GC and later are not vulnerable. First fixed in Release 15.2T
Releases prior to 15.2(3)GC are vulnerable; Releases 15.2(3)GC and later are not vulnerable. First fixed in Release 15.2T
15.2JA Not vulnerable
Not Vulnerable
15.2M Not vulnerable

Not vulnerable
15.2S Not vulnerable

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.2(1)S2
15.2(2)S1
15.2(4)S

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.2SNG Not vulnerable
Not vulnerable
15.2T 15.2(1)T3
15.2(2)T2
15.2(3)T
15.2(1)T3
15.2(2)T2
15.2(3)T2; Available on 12-OCT-12

Cisco IOS XE Software

Cisco IOS XE Software Release First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication
2.1.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.2.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.3.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.4.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.5.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
2.6.x Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.1.xS Not vulnerable 3.1.4S
3.1.xSG Not vulnerable Vulnerable; migrate to 3.2.5SG or later.
3.2.xS Not vulnerable Not vulnerable
3.2.xSG Not vulnerable 3.2.5SG
3.2.xXO Not vulnerable Vulnerable; migrate to 3.3.1SG or later.
3.3.xS Not vulnerable Vulnerable; migrate to 3.6.0S or later.
3.3.x.SG 3.3.1SG 3.3.1SG
3.4.xS Vulnerable; migrate to 3.6.0S or later. Vulnerable; migrate to 3.6.0S or later.
3.5.xS Vulnerable; migrate to 3.6.0S or later. Vulnerable; migrate to 3.6.0S or later.
3.6.xS Not vulnerable Not vulnerable
3.7.xS Not vulnerable Not vulnerable

For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to Cisco IOS XE 2 Release Notes, Cisco IOS XE 3S Release Notes, and Cisco IOS XE 3SG Release Notes.

Cisco IOS XR Software

Cisco IOS XR Software is not affected by the vulnerability that is disclosed in this document.



Workarounds

If the affected Cisco IOS device requires SIP and pass-through of SDP for VoIP services, then SIP and SDP pass-through cannot be disabled and no workarounds are available. Users are advised to apply mitigation techniques to help limit exposure to the vulnerabilities. Mitigation consists of allowing only legitimate devices to connect to affected devices. To increase effectiveness, the mitigation must be coupled with anti-spoofing measures on the network edge. This action is required because SIP can use UDP as the transport protocol.

Additional mitigations that can be deployed on Cisco devices within the network are available in the companion document "Identifying and Mitigating Exploitation of the Cisco Unified Communications Manager and Cisco IOS Software Session Initiation Protocol Denial of Service Vulnerability", which is available at the following link:
 
http://tools.cisco.com/security/center/viewAMBAlert.x?alertId=26765

Disabling SIP Listening Ports

For devices that do not require SIP to be enabled, the simplest and most effective workaround is to disable SIP processing on the device. Some versions of Cisco IOS Software allow administrators to disable SIP with the following commands:

sip-ua
 no transport udp
 no transport tcp
 no transport tcp tls

warningWarning: When applying this workaround to devices that are processing Media Gateway Control Protocol (MGCP) or H.323 calls, the devices will not stop SIP processing while active calls are being processed. Under these circumstances, this workaround should be implemented during a maintenance window when active calls can be briefly stopped.

The show udp connections, show tcp brief all, and show processes | include SIP commands can be used to confirm that the SIP UDP and TCP ports are closed after applying this workaround.

Depending on the Cisco IOS Software version in use, when SIP is disabled the output from the show ip sockets command may still show the SIP ports open, but sending traffic to them will cause the SIP process to emit the following message:

*Jul 27 15:22:41.251: sip_udp_sock_process_read: SIP UDP Listener is DISABLED

Disabling SDP Pass-Through

If SIP must remain enabled, but SDP pass-through is not required, then disabling SDP pass-through can be used as a workaround. SDP pass-through is disabled by default. SDP pass-through can be enabled at the global level, or at the dial peer level. Refer to the section "Affected Products" for details on how to disable SDP pass-through.

Control Plane Policing

For devices that must offer SIP services, it is possible to use Control Plane Policing (CoPP) to block SIP traffic to the device from untrusted sources. Cisco IOS Releases 12.0S, 12.2SX, 12.2S, 12.3T, 12.4, and 12.4T support the CoPP feature. CoPP may be configured on a device to protect the management and control planes to minimize the risk and effectiveness of direct infrastructure attacks by explicitly permitting only authorized traffic sent to infrastructure devices in accordance with existing security policies and configurations. The following example can be adapted to specific network configurations:

!-- The 192.168.1.0/24 network and the 172.16.1.1 host are trusted.
!-- Everything else is not trusted. The following access list is used
!-- to determine what traffic needs to be dropped by a control plane
!-- policy (the CoPP feature): if the access list matches (permit)
!-- then traffic will be dropped and if the access list does not
!-- match (deny) then traffic will be processed by the router.
access-list 100 deny udp 192.168.1.0 0.0.0.255 any eq 5060
access-list 100 deny tcp 192.168.1.0 0.0.0.255 any eq 5060
access-list 100 deny tcp 192.168.1.0 0.0.0.255 any eq 5061
access-list 100 deny udp host 172.16.1.1 any eq 5060
access-list 100 deny tcp host 172.16.1.1 any eq 5060
access-list 100 deny tcp host 172.16.1.1 any eq 5061
access-list 100 permit udp any any eq 5060
access-list 100 permit tcp any any eq 5060
access-list 100 permit tcp any any eq 5061

!-- Permit (Police or Drop)/Deny (Allow) all other Layer3 and Layer4
!-- traffic in accordance with existing security policies and
!-- configurations for traffic that is authorized to be sent
!-- to infrastructure devices.
!-- Create a Class-Map for traffic to be policed by
!-- the CoPP feature.
class-map match-all drop-sip-class
  match access-group 100

!-- Create a Policy-Map that will be applied to the
!-- Control-Plane of the device.
policy-map control-plane-policy
 class drop-sip-class
  drop

!-- Apply the Policy-Map to the Control-Plane of the
!-- device.
control-plane
 service-policy input control-plane-policy

Note: Because SIP can use UDP as a transport protocol, it is possible to spoof the source address of an IP packet, which may bypass access control lists that permit communication to these ports from trusted IP addresses.

In the preceding CoPP example, the access control entries (ACEs) that match the potential exploit packets with the permit action result in these packets being discarded by the policy-map drop function, while packets that match the deny action (not shown) are not affected by the policy-map drop function. Additional information on the configuration and use of the CoPP feature can be found at http://www.cisco.com/web/about/security/intelligence/coppwp_gs.html and http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gtrtlimt.html.

Obtaining Fixed Software

Cisco has released free software updates that address the vulnerability described in this advisory. Prior to deploying software, customers are advised to consult their maintenance providers or check the software for feature set compatibility and known issues that are specific to their environments.

Customers may only install and expect support for feature sets they have purchased. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license at http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html.

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, upgrades should be obtained through the Software Navigator on Cisco.com at http://www.cisco.com/cisco/software/navigator.html.

Customers Using Third-Party Support Organizations

Customers with Cisco products that 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 organization for assistance with the appropriate course of action.

The effectiveness of any workaround or fix depends on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Because of the variety of affected products and releases, customers should consult their service providers or support organizations to ensure that any applied workaround or fix is the most appropriate in the intended network before it is deployed.

Customers Without Service Contracts

Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC):

  • +1 800 553 2447 (toll free from within North America)
  • +1 408 526 7209 (toll call from anywhere in the world)
  • e-mail: tac@cisco.com

Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Customers without service contracts should request free upgrades through the TAC.

Refer to Cisco Worldwide Contacts at http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, instructions, and e-mail addresses for support in various languages.

Exploitation and Public Announcements

The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

This vulnerability was found during troubleshooting of TAC service requests.

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 Security Intelligence Operations at the following link:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-sip

Additionally, a text version of this advisory is clear signed with the Cisco PSIRT PGP key and circulated among the following e-mail addresses:

  • cust-security-announce@cisco.com
  • first-bulletins@lists.first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk

Future updates of this advisory, if any, will reside on Cisco.com but may not be announced on mailing lists. Users can monitor this advisory's URL for any updates.


Revision History

Revision 1.1 2012-October-03 Clarify that Cisco Unified Border Element (SP Edition) is not affected.
Revision 1.0 2012-September-26 Initial public release.

Cisco Security Procedures

Complete information about reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco is available on Cisco.com at http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html. This web page includes instructions for press inquiries regarding Cisco Security Advisories. All Cisco Security Advisories are available at http://www.cisco.com/go/psirt.
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