[apops] Cisco Security Advisory: Cisco IOS Software Session Initiation P

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  • Subject: [apops] Cisco Security Advisory: Cisco IOS Software Session Initiation Protocol Denial of Service Vulnerability
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  • Date: Wed, 23 Sep 2009 12:15:00 -0400
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      Cisco Security Advisory: Cisco IOS Software Session Initiation
      Protocol Denial of Service Vulnerability
      
      Advisory ID: cisco-sa-20090923-sip
      
      Revision 1.0
      
      For Public Release 2009 September 23
      
      +---------------------------------------------------------------------
      
      Summary
      =======
      
      A vulnerability exists in the Session Initiation Protocol (SIP)
      implementation in Cisco IOS® Software that could allow an
      unauthenticated attacker to cause a denial of service (DoS) condition
      on an affected device when the Cisco Unified Border Element feature
      is enabled.
      
      Cisco has released free software updates that address this
      vulnerability. For devices that must run SIP there are no
      workarounds; however, mitigations are available to limit exposure of
      the vulnerability.
      
      This advisory is posted at:
      
      http://www.cisco.com/warp/public/707/cisco-sa-20090923-sip.shtml
      
      Note: The September 23, 2009, Cisco IOS Security Advisory bundled
      publication includes eleven Security Advisories. Ten of the
      advisories address vulnerabilities in Cisco IOS Software, and one
      advisory addresses a vulnerability in Cisco Unified Communications
      Manager. Each advisory lists the releases that correct the
      vulnerability or vulnerabilities detailed in the advisory. The
      following table lists releases that correct all Cisco IOS Software
      vulnerabilities that have been published on September 23, 2009, or
      earlier.
      
      http://www.cisco.com/warp/public/707/cisco-sa-20090923-bundle.shtml
      
      Individual publication links are in "Cisco Event Response: Semiannual
      Cisco IOS Software Advisory Bundled Publication" at the following
      link:
      
      http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep09.html
      
      Affected Products
      =================
      
      This vulnerability only affects devices running Cisco IOS Software
      with SIP voice services enabled.
      
      Vulnerable Products
      +------------------
      
      Cisco devices running affected Cisco IOS Software versions that are
      configured to process SIP messages with the Cisco Unified Border
      Element feature are affected. Cisco IOS devices that are not
      configured for SIP and Cisco Unified Border Element feature are not
      affected by this vulnerability.
      
      Note: Cisco Unified Border Element feature (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.
      
      Cisco Unified Border Element feature requires the "voice service voip" 
      command and the "allow-connections" subcommand. An example of an
      affected configuration is as follows:
      
           voice service voip
             allow-connections from-type to to-type 
          ...
          !
      
      Recent versions of Cisco IOS Software do not process SIP messages by
      default. Creating a dial peer by issuing the command "dial-peer voice"
      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, once configured will
      also automatically start the SIP process, which will cause the device
      to start processing SIP messages. An example of an affected
      configuration is as follows:
      
          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 command show processes | include SIP
      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 is processing 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
      
      warning Warning: Since 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.
      
      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 12.3(26) with an installed image name of
      C2500-IS-L:
      
          Router#show version
          Cisco Internetwork Operating System Software
          IOS (tm) 2500 Software (C2500-IS-L), Version 12.3(26), RELEASE SOFTWARE (fc2)
          Technical Support: http://www.cisco.com/techsupport
          Copyright (c) 1986-2008 by cisco Systems, Inc.
          Compiled Mon 17-Mar-08 14:39 by dchih
          
          
          !--- output truncated
          
      
      The following example identifies a Cisco product that is running
      Cisco IOS Software Release 12.4(20)T with an installed image name of
      C1841-ADVENTERPRISEK9-M:
      
          Router#show version
          Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 12.4(20)T, RELEASE SOFTWARE (fc3)
          Technical Support: http://www.cisco.com/techsupport
          Copyright (c) 1986-2008 by Cisco Systems, Inc.
          Compiled Thu 10-Jul-08 20:25 by prod_rel_team
          
          
          !--- output truncated
          
      
      Additional information about Cisco IOS Software release naming
      conventions is available in "White Paper: Cisco IOS Reference Guide"
      at the following link:
      
      http://www.cisco.com/warp/public/620/1.html
      
      Products Confirmed Not Vulnerable
      +--------------------------------
      
      The SIP Application Layer Gateway (ALG), which is used by the Cisco
      IOS NAT and firewall features of Cisco IOS Software, is not affected
      by this vulnerability. Cisco IOS XE Software and Cisco IOS XR
      Software are not affected by this vulnerability. No other Cisco
      products are currently known to be affected by this vulnerability.
      
      Details
      =======
      
      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 TLS (TCP port
      5061) as the underlying transport protocol.
      
      The Cisco Unified Border Element (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.
      
      For more information about Cisco Unified Border Element refer to the
      following link:
      
      http://www.cisco.com/en/US/products/sw/voicesw/ps5640/index.html
      
      A DoS vulnerability exists in the SIP implementation in Cisco IOS
      Software when devices are running a Cisco IOS image that contains the
      Cisco Unified Border Element feature. This vulnerability is triggered
      by processing a series of crafted SIP messages.
      
      This vulnerability is documented in Cisco Bug ID CSCsx25880 and has been
      assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2009-2870.
      
      Vulnerability Scoring Details
      =============================
      
      Cisco has provided scores for the vulnerability 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
      
      CSCsx25880 - Crafted SIP packet may cause device reload
      
      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 vulnerability described in this
      document may result in a reload of the device. The issue could be
      repeatedly exploited to cause an extended DoS condition.
      
      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.
      
      Each row of the Cisco IOS Software table (below) names a Cisco IOS
      release train. If a given release train is vulnerable, then the
      earliest possible releases that contain the fix (along with the
      anticipated date of availability for each, if applicable) are listed
      in the "First Fixed Release" column of the table. The "Recommended
      Release" column indicates the releases which have fixes for all the
      published vulnerabilities at the time of this Advisory. A device
      running a release in the given train that is earlier than the release
      in a specific column (less than the First Fixed Release) is known to
      be vulnerable. Cisco recommends upgrading to a release equal to or
      later than the release in the "Recommended Releases" column of the
      table.
      
      +-------------------------------------------------------------------+
      |   Major    |          Availability of Repaired Releases           |
      |  Release   |                                                      |
      |------------+------------------------------------------------------|
      |  Affected  |                                       | Recommended  |
      | 12.0-Based |          First Fixed Release          |   Release    |
      |  Releases  |                                       |              |
      |-------------------------------------------------------------------|
      | There are no affected 12.0 based releases.                        |
      |-------------------------------------------------------------------|
      |  Affected  |                                       | Recommended  |
      | 12.1-Based |          First Fixed Release          |   Release    |
      |  Releases  |                                       |              |
      |-------------------------------------------------------------------|
      | There are no affected 12.1 based releases.                        |
      |-------------------------------------------------------------------|
      |  Affected  |                                       | Recommended  |
      | 12.2-Based |          First Fixed Release          |   Release    |
      |  Releases  |                                       |              |
      |-------------------------------------------------------------------|
      | There are no affected 12.2 based releases.                        |
      |-------------------------------------------------------------------|
      |  Affected  |                                       | Recommended  |
      | 12.3-Based |          First Fixed Release          |   Release    |
      |  Releases  |                                       |              |
      |------------+---------------------------------------+--------------|
      | 12.3       | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3B      | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3BC     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3BW     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3EU     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JA     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JEA    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JEB    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JEC    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JK     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JL     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3JX     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3T      | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3TPC    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3VA     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XA     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XB     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XC     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XD     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XE     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XF     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XG     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XI     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XJ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XK     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XL     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XQ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XR     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XS     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XU     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XW     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XX     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XY     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3XZ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YA     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YD     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YF     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YG     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YH     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YI     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YJ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            | Releases prior to 12.3(11)YK3 are     | 12.4(20)T4   |
      |            | vulnerable, release 12.3(11)YK3 and   |              |
      | 12.3YK     | later are not vulnerable; first fixed | 12.4(22)T3   |
      |            | in 12.4T                              |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      | 12.3YM     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YQ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            | Vulnerable; first fixed in 12.4T      | 12.4(20)T4   |
      |            |                                       |              |
      | 12.3YS     | Releases up to and including 12.3(11) | 12.4(22)T3   |
      |            | YS1 are not vulnerable.               |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.3YT     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      | 12.3YU     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YX     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3YZ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.3ZA     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |  Affected  |                                       | Recommended  |
      | 12.4-Based |          First Fixed Release          |   Release    |
      |  Releases  |                                       |              |
      |------------+---------------------------------------+--------------|
      | 12.4       | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4GC     | 12.4(24)GC1                           |              |
      |------------+---------------------------------------+--------------|
      | 12.4JA     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JDA    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JDC    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JDD    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JK     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JL     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JMA    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JMB    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4JX     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4MD     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4MDA    | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4MR     | 12.4(19)MR3                           | 12.4(19)MR3  |
      |------------+---------------------------------------+--------------|
      | 12.4SW     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            | 12.4(24)T1                            |              |
      |            |                                       | 12.4(20)T4   |
      |            | 12.4(15)T10                           |              |
      | 12.4T      |                                       | 12.4(22)T3   |
      |            | 12.4(20)T3                            |              |
      |            |                                       | 12.4(24)T2;  |
      |            | 12.4(22)T2                            | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XA     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XB     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XC     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XD     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XE     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      | 12.4XF     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4XG     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XJ     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      | 12.4XK     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4XL     | 12.4(15)XL5                           |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            | Vulnerable; first fixed in 12.4T      | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XM     | Releases up to and including 12.4(15) | 12.4(22)T3   |
      |            | XM are not vulnerable.                |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      | 12.4XN     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |            | Vulnerable; Contact your support      |              |
      | 12.4XP     | organization per the instructions in  |              |
      |            | Obtaining Fixed Software section of   |              |
      |            | this advisory                         |              |
      |------------+---------------------------------------+--------------|
      | 12.4XQ     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4XR     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XT     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            | Vulnerable; Contact your support      |              |
      | 12.4XV     | organization per the instructions in  |              |
      |            | Obtaining Fixed Software section of   |              |
      |            | this advisory                         |              |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XW     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XY     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4XZ     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      |            |                                       | 12.4(15)T10  |
      |            |                                       |              |
      |            |                                       | 12.4(20)T4   |
      |            |                                       |              |
      | 12.4YA     | Vulnerable; first fixed in 12.4T      | 12.4(22)T3   |
      |            |                                       |              |
      |            |                                       | 12.4(24)T2;  |
      |            |                                       | Available on |
      |            |                                       | 23-OCT-2009  |
      |------------+---------------------------------------+--------------|
      | 12.4YB     | 12.4(22)YB1                           | 12.4(22)YB4  |
      |------------+---------------------------------------+--------------|
      | 12.4YD     | Not Vulnerable                        |              |
      |------------+---------------------------------------+--------------|
      | 12.4YE     | Not Vulnerable                        |              |
      +-------------------------------------------------------------------+
      
      Note: No Cisco IOS-XE or Cisco IOS Software Modularity releases are
      affected by this vulnerability.
      
      Workarounds
      ===========
      
      If the affected Cisco IOS device requires SIP for VoIP services, SIP
      cannot be disabled, and therefore, no workarounds are available.
      Users are advised to apply mitigation techniques to help limit
      exposure to the vulnerability. Mitigation consists of allowing only
      legitimate devices to connect to the routers. 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 "Cisco Applied
      Mitigation Bulletin: Identifying and Mitigating Exploitation of the
      Denial of Service Vulnerabilities in Cisco Unified Communications
      Manager and Cisco IOS Software", which is available at the following
      location:
      
      http://www.cisco.com/warp/public/707/cisco-amb-20090923-voice.shtml
      
      Disable 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
      accomplish this with the following commands:
      
          sip-ua
           no transport udp
           no transport tcp
           no transport tcp tls
      
      Warning: When applying this workaround to devices that are
      processing Media Gateway Control Protocol (MGCP) or H.323 calls, the
      device 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, the output of
      "show ip sockets" still showed UDP port 5060 open, but sending
      something to that port caused the SIP process to emit the following
      message:
      
          *Feb  2 11:36:47.691: sip_udp_sock_process_read: SIP UDP Listener is
          DISABLED 
      
      Control Plane Policing
      +---------------------
      
      For devices that need to 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 the network
      
          
          !-- 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 drop-sip-traffic
           class drop-sip-class
            drop
          
          
          !-- Apply the Policy-Map to the Control-Plane of the
          !-- device.
          
          
          control-plane
           service-policy input drop-sip-traffic
      
      Warning: Because SIP can use UDP as a transport protocol, it
      is possible to easily spoof the IP address of the sender, which may
      defeat access control lists that permit communication to these ports
      from trusted IP addresses.
      
      In the above 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 these
      vulnerabilities. Prior to deploying software, customers should
      consult their maintenance provider or check the software for feature
      set compatibility and known issues specific to their environment.
      
      Customers may only install and expect support for the feature sets
      they have purchased. By installing, downloading, accessing or
      otherwise using such software upgrades, customers agree to be bound
      by the terms of Cisco's software license terms found at:
      
      http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.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 at cisco dot com or security-alert at cisco dot com 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 at cisco dot com
      
      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/en/US/support/tsd_cisco_worldwide_contacts.html
      
      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 vulnerability described in this advisory.
      
      This vulnerability was discovered during internal testing.
      
      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-20090923-sip.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 at cisco dot com
        * first-bulletins at lists dot first dot org
        * bugtraq at securityfocus dot com
        * vulnwatch at vulnwatch dot org
        * cisco at spot dot colorado dot edu
        * cisco-nsp at puck dot nether dot net
        * full-disclosure at lists.grok dot org dot uk
        * comp.dcom.sys.cisco at newsgate dot cisco dot com
      
      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      | 2009-September-23 | 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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