[apops] Cisco Security Advisory: Cisco IOS XR MPLS Vulnerabilities

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  • Subject: [apops] Cisco Security Advisory: Cisco IOS XR MPLS Vulnerabilities
  • From: Cisco Systems Product Security Incident Response Team <psirt at cisco dot com>
  • Date: Wed, 19 Apr 2006 17:00:00 +0200
  • Cc: psirt at cisco dot com
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      Cisco Security Advisory: Cisco IOS XR MPLS Vulnerabilities
      
      Advisory ID: cisco-sa-20060419-xr
      
      http://www.cisco.com/warp/public/707/cisco-sa-20060419-xr.shtml
      
      Revision 1.0
      
      For Public Release 2006 April 19 1500 UTC (GMT)
      
      - ---------------------------------------------------------------------
      
      Contents
      ========
      
          Summary
          Affected Products
          Details
          Impact
          Software Version and Fixes
          Workarounds
          Obtaining Fixed Software
          Exploitation and Public Announcements
          Status of this Notice: FINAL
          Distribution
          Revision History
          Cisco Security Procedures
      
      - ---------------------------------------------------------------------
      
      Summary
      =======
      
      Multiple Multi Protocol Label Switching (MPLS) related
      vulnerabilities exist on Cisco IOS  XR. Only systems that are running
      Cisco IOS XR and configured for MPLS are affected by these
      vulnerabilities.
      
      Upon successful exploitation a Modular Services Card (MSC) on a Cisco
      Carrier Routing System 1 (CRS-1) or a Line Card (LC) on a Cisco 12000
      series router may reload affecting switched traffic.
      
      Cisco has made free software available to address this vulnerability
      for affected customers.
      
      This advisory is posted at 
      http://www.cisco.com/warp/public/707/cisco-sa-20060419-xr.shtml.
      
      Affected Products
      =================
      
      Vulnerable Products
      +------------------
      
      Only systems that are running Cisco IOS XR and configured for MPLS
      are affected by this vulnerability.
      
      Systems that are running Cisco IOS XR and configured for MPLS can be
      identified by the show mpls interfaces command. A sample output of
      this command on a CRS-1 that is configured for MPLS is given below.
      
            RP/0/RP1/CPU0:crs1#show mpls interfaces
            Interface                  LDP      Tunnel   Enabled
            -------------------------- -------- -------- --------
            POS0/2/0/0                 Yes      Yes      Yes
            POS0/2/0/1                 No       Yes      Yes
            POS0/2/0/2                 Yes      No       Yes
            POS0/2/0/3                 Yes      Yes      Yes
            GigabitEthernet0/3/1/0     Yes      No       Yes
            GigabitEthernet0/3/1/3     Yes      No       Yes
            POS0/3/0/1                 Yes      Yes      Yes
            TenGigE0/6/0/0             Yes      No       Yes
            RP/0/RP1/CPU0:crs#
      
      
      In the above output, the fourth column labeled Enabled identifies
      MPLS enabled interfaces.
      
      Products Confirmed Not Vulnerable
      +--------------------------------
      
      Cisco IOS XR only runs on CRS-1 or Cisco 12000 series routers. Other
      Cisco products, including systems that run Cisco IOS are not
      affected.
      
      Details
      =======
      
      Cisco IOS XR Software is a member of the Cisco IOS Software Family
      that uses a microkernel based distributed operating system
      infrastructure. Cisco IOS XR runs both on Cisco CRS-1 and Cisco 12000
      series routers.
      
      More information on Cisco IOS XR can be found at the following URL:
      
      http://www.cisco.com/en/US/products/ps5845/index.html
      
      Modular Services Cards (MSC), also called the line cards are Layer-3
      forwarding engines on Cisco CRS-1. An MSC is paired with a physical
      layer interface module (PLIM) which provides layer-1 and layer-2
      services.
      
      More information on Cisco CRS-1 architecture can be found at the
      following URL:
      
      http://www.cisco.com/en/US/products/ps5763/index.html
      
      Specific MPLS packets that are switched by a Cisco CRS-1 or a 12000
      series system will restart the NetIO process. If the NetIO process is
      restarted several times consecutively, the line card will reload
      causing a Denial of Service (DoS) condition for the traffic that is
      being switched on that line card.
      
      MPLS packets will be forwarded through the MPLS network. Therefore,
      packets that can trigger this vulnerability can be sent from remote
      systems that are in the MPLS network. Such packets can not be
      received on interfaces that are not configured for MPLS.
      
      This vulnerability is addressed by the following Cisco bug IDs:
      
        * CSCsd15970 -- MSC crash upon receipt of specific MPLS packets
          This bug only affects CRS-1 and does not affect Cisco 12000
          series routers that are running Cisco IOS XR.
      
        * CSCsd55531 -- MPLS packet handling problems
          This bug only affects CRS-1 and does not affect Cisco 12000
          series routers that are running Cisco IOS XR.
      
        * CSCsc77475 -- Line card crash upon receipt of specific MPLS
          packets
          This bug affects both CRS-1 and Cisco 12000 series routers that
          are running Cisco IOS XR.
      
      
      Impact
      ======
      
      Successful exploitation of the vulnerability may result in a reload
      of the Modular Services Card (MSC) on a CRS-1 or the line cards on a
      Cisco 12000 series router. Repeated exploitation could result in a
      sustained DoS attack.
      
      Software Version and Fixes
      ==========================
      
      When considering software upgrades, also consult 
      http://www.cisco.com/go/psirt and any subsequent advisories to 
      determine exposure and a complete upgrade solution.
      
      In all cases, customers should exercise caution to be certain the
      devices to be upgraded contain sufficient memory and that current
      hardware and software configurations will continue to be supported
      properly by the new release. If the information is not clear, contact
      the Cisco Technical Assistance Center ("TAC") or your contracted
      maintenance provider for assistance.
      
      +---------------------------------------+
      | Cisco IOS XR  | SMU ID                |
      | Version       |                       |
      |---------------+-----------------------|
      | 3.2.0         | AA01447               |
      |---------------+-----------------------|
      | 3.2.1         | AA01446               |
      |---------------+-----------------------|
      | 3.2.2         | AA01448               |
      |---------------+-----------------------|
      | 3.2.3 for     | AA01444               |
      | CRS-1         |                       |
      |---------------+-----------------------|
      | 3.2.3 for PRP | AA01451               |
      |---------------+-----------------------|
      | 3.2.4         | AA01449               |
      |---------------+-----------------------|
      | 3.2.50        | AA01450               |
      |---------------+-----------------------|
      | 3.3           | Cisco IOS XR 3.3 is   |
      |               | not vulnerable        |
      +---------------------------------------+
      
      Workarounds
      ===========
      
      There is no workaround to mitigate the effects of these
      vulnerabilities.
      
      Obtaining Fixed Software
      ========================
      
      Cisco will make free software available to address this vulnerability
      for affected customers. This advisory will be updated as fixed
      software becomes available. Prior to deploying software, customers
      should consult their maintenance provider or check the software for
      feature set compatibility and known issues specific to their
      environment.
      
      Customers may only install and expect support for the feature sets
      they have purchased. By installing, downloading, accessing or
      otherwise using such software upgrades, customers agree to be bound
      by the terms of Cisco's software license terms found at 
      http://www.cisco.com/public/sw-license-agreement.html , or as otherwise 
      set forth at Cisco.com Downloads at 
      http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
      
      Do not contact either "psirt 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
      TAC.
      
      Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
      for additional TAC contact information, including special localized
      telephone numbers and instructions and e-mail addresses for use in
      various languages.
      
      Exploitation and Public Announcements
      =====================================
      
      The Cisco PSIRT is not aware of any public announcements or malicious
      use of the vulnerability described in this advisory.
      
      This vulnerability was reported to Cisco by a customer.
      
      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-20060419-xr.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-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      | 2006-April-19 | 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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