[apops] Cisco Security Advisory: Cisco Catalyst 6000, 6500 and Cisco 760

  • To: apops at apops dot net
  • Subject: [apops] Cisco Security Advisory: Cisco Catalyst 6000, 6500 and Cisco 7600 Series MPLS Packet Vulnerability
  • From: Cisco Systems Product Security Incident Response Team <psirt at cisco dot com>
  • Date: Wed, 28 Feb 2007 17:00:00 +0100
  • Cc: psirt at cisco dot com
  • List-archive: <http://www.apnic.net/mailing-lists/apops>
  • List-help: <mailto:apops-request@apops.net?subject=help>
  • List-id: Asia Pacific Operators Forum <apops.apops.net>
  • List-post: <mailto:apops@apops.net>
  • List-subscribe: <http://mailman.apnic.net/mailman/listinfo/apops>, <mailto:apops-request@apops.net?subject=subscribe>
  • List-unsubscribe: <http://mailman.apnic.net/mailman/listinfo/apops>, <mailto:apops-request@apops.net?subject=unsubscribe>
  • Prevent-nondelivery-report:
  • Reply-to: psirt@cisco.com
  • Sender: nobody@cisco.com
    • Hash: SHA1
      Cisco Security Advisory: Cisco Catalyst 6000, 6500 and Cisco 7600
      Series MPLS Packet Vulnerability
      Advisory ID: cisco-sa-20070228-mpls
      Revision 1.0
      For Public Release 2007 February 28 
      - ---------------------------------------------------------------------
      Cisco Catalyst 6500 series systems that are running certain versions
      of Cisco Internetwork Operating System (IOS) are vulnerable to an
      attack from a Multi Protocol Label Switching (MPLS) packet. Only the
      systems that are running in Hybrid Mode (Catalyst OS (CatOS) software
      on the Supervisor Engine and IOS Software on the Multilayer Switch
      Feature Card (MSFC)) or running with Cisco IOS Software Modularity
      are affected.
      MPLS packets can only be sent from the local network segment.
      This advisory is posted at 
      Affected Products
      Vulnerable Products
      The following products are affected by this vulnerability:
        * Cisco Catalyst 6500 systems that run 12.2(18)SXF4 with Cisco IOS
          Software Modularity are affected.
          Images that support Cisco IOS Software Modularity have a "-vz"
          suffix in their image name.
          The following is a conclusive list of all image names that are
          running with Cisco IOS Software Modularity and are affected by
          this vulnerability.
            + s72033-adventerprisek9_wan-vz.122-18.SXF4.bin
            + s72033-advipservicesk9_wan-vz.122-18.SXF4.bin
            + s72033-entservicesk9_wan-vz.122-18.SXF4.bin
            + s72033-ipservices_wan-vz.122-18.SXF4.bin
            + s72033-ipservicesk9_wan-vz.122-18.SXF4.bin
            + s72033-ipservicesk9-vz.122-18.SXF4.bin
        * Cisco Catalyst 6000, 6500 and Cisco 7600 series systems with an
          MSFC2 or MSFC3 that run in Hybrid Mode are affected.
          In Hybrid Mode, Catalyst OS (CatOS) software runs on the
          Supervisor Engine and IOS runs on the MSFC. It is different from
          the Native Mode in which IOS runs both on the Supervisor Engine
          and MSFC.
          This vulnerability affects MSFC2, MSFC2a and MSFC3 that run
          certain images in Hybrid mode.
          In Hybrid Mode, IOS images that run on MSFC start with "c6msfc2",
          "c6msfc2a" or "c6msfc3". Several image names that run on MSFC in
          hybrid mode are provided below for reference:
            + c6msfc2a-adventerprisek9_wan-mz.122-18.SXF
            + c6msfc3-jsv-mz.122-14.SX2
      Products Confirmed Not Vulnerable
        * Systems that are running in Native Mode without Cisco IOS
          Software Modularity are not affected.
        * Systems without an MSFC2, MSFC2a or MSFC3 are not affected.
      No other Cisco products are known to be affected by this
      Cisco IOS Software Modularity combines subsystems into individual
      processes and enhances the Cisco IOS Software memory architecture to
      provide process-level fault isolation and subsystem "In Service
      Software Upgrade" (ISSU) capability. These enhancements are delivered
      in Cisco IOS Software for the Catalyst 6500 Series Supervisor Engine
      720 and Supervisor Engine 32. Cisco IOS Software Modularity was first
      delivered as an option in a Cisco IOS Software Release 12.2(18)SXF4.
      More information on Modular IOS can be found at the following URL:
      Not all 12.2(18)SXF4 images support Modular IOS. Only the images with
      a "-vz" in the image name support Modular IOS and are affected by
      this vulnerability. A conclusive list of all affected image names
      that support Cisco IOS Software Modularity is provided in the
      Affected Products section.
      In Hybrid Mode, a CatOS image is used as the system software to run
      the Supervisor Engine on the Catalyst systems. If an MSFC is
      installed, a separate IOS Software image is used in order to run the
      MSFC. CatOS provides the Layer 2 (L2) switching functionality. The
      Cisco IOS on the MSFC provides the Layer 3 (L3) routing
      functionality. It differs from the Native Mode, in which a single
      Cisco IOS Software image is used as the system software to run both
      the Supervisor Engine and MSFC on the Catalyst systems. IOS software
      that runs on MSFC in Hybrid Mode is also affected by this
      vulnerability. More information about the differences between Hybrid
      and Native Modes can be found at the following URL:
      MPLS packets received by a Route Processor (MSFC) Layer 3 interface
      can potentially trigger this vulnerability. The system in question
      does not need to be configured for MPLS to be vulnerable. MPLS
      packets can only be sent from the local network segment, limiting the
      scope of the exploitation.
      This issue is documented in bug IDs CSCsd37415 ( registered customers
      only) and CSCef90002 ( registered customers only) .
      Vulnerability Scoring Details
      Cisco is providing scores for the vulnerabilities in this advisory
      based on the Common Vulnerability Scoring System (CVSS). Cisco will
      provide a base and temporal score. Customers can then compute
      environmental scores to assist in determining the impact of the
      vulnerability in individual networks.
      Cisco PSIRT will set the bias in all cases to normal. Customers are
      encouraged to apply the bias parameter when determining the
      environmental impact of a particular vulnerability.
      CVSS is a standards-based scoring method that conveys vulnerability
      severity and helps determine urgency and priority of response.
      Cisco has provided an FAQ to answer additional questions regarding
      CVSS at 
      Cisco has also provided a CVSS calculator to help compute the
      environmental impact for individual networks at 
      CSCsd37415 - RP crashed on sending MPLS packet to a interface
      CVSS Base Score: 3.3
      - - Access Vector: Remote
      - - Access Complexity: Low
      - - Authentication: Not Required
      - - Confidentiality Impact: None
      - - Integrity Impact: None
      - - Availability Impact: Complete
      - - Impact Bias: Normal
      CVSS Temporal Score: 2.7
      - - Exploitability: Functional
      - - Remediation Level: Official Fix
      - - Report Confidence: Confirmed
      CSCef90002 - MSFC crashed due to corrupted program counter
      CVSS Base Score: 3.3
      - - Access Vector: Remote
      - - Access Complexity: Low
      - - Authentication: Not Required
      - - Confidentiality Impact: None
      - - Integrity Impact: None
      - - Availability Impact: Complete
      - - Impact Bias: Normal
      CVSS Temporal Score: 2.7
      - - Exploitability: Functional
      - - Remediation Level: Official Fix
      - - Report Confidence: Confirmed
      Successful exploitation of the vulnerability may result in the reload
      of the system on systems that are running with Cisco IOS Software
      Modularity and the reload of MSFC on systems that are running in
      Hybrid Mode.
      Repeated exploitation may lead to a denial of service condition.
      Software Version and Fixes
      When considering software upgrades, also consult 
      http://www.cisco.com/go/psirt and any subsequent advisories to 
      determine exposure and a complete upgrade solution.
      In all cases, customers should exercise caution to be certain that
      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) describes a release
      train and the platforms or products for which it is intended. If a
      given release train is vulnerable, then the earliest possible
      releases that contain the fix (the "First Fixed Release") and the
      anticipated date of availability for each are listed in the "Rebuild"
      and "Maintenance" columns. 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. The release
      should be upgraded at least to the indicated release or a later
      version (greater than or equal to the First Fixed Release label).
      For more information on the terms "Rebuild" and "Maintenance,"
      consult the following URL: 
      |         |    Availability of Fixed    |
      | Trains  |          Releases           |
      |         |-----------------------------|
      |         |    Rebuild    | Maintenance |
      | 12.1E   | Not vulnerable              |
      | 12.2SXA | Vulnerable. Migrate to 12.2 |
      |         | (17d)SXB5 or later          |
      | 12.2SXB | 12.2(17d)SXB5 |             |
      | 12.2SXD | 12.2(18)SXD3  |             |
      | 12.2SXE | Not vulnerable              |
      | 12.2SXF | 12.2(18)SXF5  |             |
      | (*)     |               |             |
      * Only 12.2(18)SXF4 with IOS Software Modularity is affected. 12.2SXF
      releases that run in Hybrid Mode are not affected. Please see the
      Affected Products section for more information.
      A special patch for 12.2(18)SXF4 with Cisco IOS Software Modularity
      is also available.
      Patch Name: MA0045
      Image Name: s72033-AMA0045-patch.122-18.SXF4
      The above patch can be downloaded from the Cisco IOS Software
      Modularity Patch Navigator at 
      There are no workarounds for this vulnerability.
      Additional mitigations that can be deployed on Cisco devices within
      the network are available in the Cisco Applied Intelligence companion
      document for this advisory: 
      Obtaining Fixed Software
      Cisco will make free software available to address this vulnerability
      for affected customers. This advisory will be updated as fixed
      software becomes available. Prior to deploying software, customers
      should consult their maintenance provider or check the software for
      feature set compatibility and known issues specific to their
      Customers may only install and expect support for the feature sets
      they have purchased. By installing, downloading, accessing or
      otherwise using such software upgrades, customers agree to be bound
      by the terms of Cisco's software license terms found at 
      http://www.cisco.com/public/sw-license-agreement.html, or as 
      otherwise set forth at Cisco.com Downloads at 
      Do not contact either "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 agreement with third-party support organizations
      such as Cisco Partners, authorized resellers, or service providers
      should contact that support organization for guidance and assistance
      with the appropriate course of action in regards to this advisory.
      The effectiveness of any workaround or fix is dependent on specific
      customer situations such as product mix, network topology, traffic
      behavior, and organizational mission. Due to the variety of affected
      products and releases, customers should consult with their service
      provider or support organization to ensure any applied workaround or
      fix is the most appropriate for use in the intended network before it
      is deployed.
      Customers without Service Contracts
      Customers who purchase direct from Cisco but who do not hold a Cisco
      service contract and customers who purchase through third-party
      vendors but are unsuccessful at obtaining fixed software through
      their point of sale should get their upgrades by contacting the Cisco
      Technical Assistance Center (TAC). TAC contacts are as follows.
        * +1 800 553 2447 (toll free from within North America)
        * +1 408 526 7209 (toll call from anywhere in the world)
        * e-mail: tac at cisco dot com
      Have your product serial number available and give the URL of this
      notice as evidence of your entitlement to a free upgrade. Free
      upgrades for non-contract customers must be requested through the
      Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
      for additional TAC contact information, including special localized
      telephone numbers and instructions and e-mail addresses for use in
      various languages.
      Exploitation and Public Announcements
      The Cisco PSIRT is not aware of any public announcements or malicious
      use of the vulnerability described in this advisory.
      This vulnerability was reported by a customer.
      Status of this Notice:FINAL
      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.
      This advisory is posted on Cisco's worldwide website at:
      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-teams at 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      | 2007-February-28 | 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 
      This includes instructions for press inquiries regarding Cisco 
      security notices. All Cisco security advisories are available 
      at http://www.cisco.com/go/psirt.
      -----BEGIN PGP SIGNATURE-----
      Version: GnuPG v1.4.6 (GNU/Linux)
      -----END PGP SIGNATURE-----