[apops] Cisco Security Advisory: Vulnerability in Cisco IOS with OSPF, M

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  • Subject: [apops] Cisco Security Advisory: Vulnerability in Cisco IOS with OSPF, MPLS VPN, and Supervisor 32, Supervisor 720, or Route Switch Processor 720
  • From: Cisco Systems Product Security Incident Response Team <psirt at cisco dot com>
  • Date: Wed, 26 Mar 2008 17:00:00 +0100
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      Cisco Security Advisory: Vulnerability in Cisco IOS with OSPF, MPLS
                               VPN, and Supervisor 32, Supervisor 720, or
                               Route Switch Processor 720
      
      Advisory ID: cisco-sa-20080326-queue
      
      http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml
      
      Revision 1.0
      
      For Public Release 2008 March 26 1600 UTC (GMT)
      
      Summary
      =======
      
      Certain Cisco Catalyst 6500 Series and Cisco 7600 Router devices that
      run branches of Cisco IOS based on 12.2 can be vulnerable to a denial
      of service vulnerability that can prevent any traffic from entering
      an affected interface. For a device to be vulnerable, it must be
      configured for Open Shortest Path First (OSPF) Sham-Link and Multi
      Protocol Label Switching (MPLS) Virtual Private Networking (VPN).
      This vulnerability only affects Cisco Catalyst 6500 Series or
      Catalyst 7600 Series devices with the Supervisor Engine 32 (Sup32),
      Supervisor Engine 720 (Sup720) or Route Switch Processor 720 (RSP720)
      modules. The Supervisor 32, Supervisor 720, Supervisor 720-3B,
      Supervisor 720-3BXL, Route Switch Processor 720, Route Switch
      Processor 720-3C, and Route Switch Processor 720-3CXL are all
      potentially vulnerable.
      
      The OSPF and MPLS VPNs are not enabled by default.
      
      This advisory is posted at 
      http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml
      
      Note: The March 26, 2008 publication includes five Security
      Advisories. The Advisories all affect Cisco IOS. Each Advisory lists
      the releases that correct the vulnerability described in the
      Advisory, and the Advisories also detail the releases that correct
      the vulnerabilities in all five Advisories. Please reference the
      following software table to find a release which fixes all published
      Security Advisories as of March 26th, 2008.
      
        * March 26th bundled IOS Advisory Table
          http://www.cisco.com/warp/public/707/cisco-sa-20080326-bundle.shtml
      
      Individual publication links are listed below:
      
        * Cisco IOS Virtual Private Dial-up Network Denial of Service
          Vulnerability
          http://www.cisco.com/warp/public/707/cisco-sa-20080326-pptp.shtml
         
        * Multiple DLSw Denial of Service Vulnerabilities in Cisco IOS
          http://www.cisco.com/warp/public/707/cisco-sa-20080326-dlsw.shtml
         
        * Cisco IOS User Datagram Protocol Delivery Issue For IPv4/IPv6
          Dual-stack Routers
          http://www.cisco.com/warp/public/707/cisco-sa-20080326-IPv4IPv6.shtml
      
        * Vulnerability in Cisco IOS with OSPF, MPLS VPN, and Supervisor
          32, Supervisor 720, or Route Switch Processor 720
          http://www.cisco.com/warp/public/707/cisco-sa-20080326-queue.shtml
         
        * Cisco IOS Multicast Virtual Private Network (MVPN) Data Leak
          http://www.cisco.com/warp/public/707/cisco-sa-20080326-mvpn.shtml
      
      
      Affected Products
      ================
      
      Vulnerable Products
      +------------------
      
      All Cisco products based on the Supervisor Engine 32 (Sup32),
      Supervisor Engine 720 (Sup720) or Route Switch Processor 720 (RSP720)
      are potentially vulnerable. Cisco Sup720 and RSP720 products have
      support for daughter cards that enhance their functionality. These
      daughter cards attach directly to the Sup720 or RSP720 and have names
      like PFC-3B, PFC-3BXL, PFC-3C, and PFC-3CXL. The product number of
      the Sup720 or RSP720 can change to reflect the daughter card that is
      installed, such as RSP720-3CXL.
      
      Because the vulnerability affects the Sup720 and RSP720, all versions
      of the Sup720 or RSP720 are vulnerable, regardless of the daughter
      card that is installed.
      
        * Cisco Catalyst 6500 Series devices with the Sup32, Sup720,
          Sup720-3B, or Sup720-3BXL
        * Cisco 7600 Series devices with the Sup32, Sup720, Sup720-3B, or
          Sup720-3BXL
        * Cisco 7600 Series devices with the RSP720, RSP720-3C, or
          RSP720-3CXL
        * Cisco ME 6524 Ethernet Switch
      
      Products Confirmed Not Vulnerable
      +--------------------------------
      
      No other Cisco products are currently known to be affected by this
      vulnerability.
      
      Cisco Bug ID CSCsf12082 was integrated into additional IOS releases 
      that do not run on the vulnerable hardware, but only the platforms 
      mentioned in the Vulnerable Products section above are affected by
      this vulnerability.
      
      Details
      =======
      
      Vulnerable Cisco devices, when configured for Multi Protocol Label
      Switching (MPLS) Virtual Private Networking (VPN) and Open Shortest
      Path First (OSPF) sham-link, can suffer from a blocked queue, 
      memory leak and/or restart of the device
      
      This vulnerability is documented in Cisco bug ID CSCsf12082, and has 
      been assigned CVE ID CVE-2008-0057.
      
      The following combination of hardware and software configuration must
      be present for the device to be vulnerable:
      
        * Cisco Catalyst Sup32, Sup720, or RSP720 is present
        * MPLS VPN is configured
        * OSPF sham-link is configured
      
      In order to determine whether you are running this feature, use the 
      show running-config command and search for the address-family vpnv4
      and area sham-link router configuration commands. The following
      command displays all configuration lines that meet the following
      criteria:
      
        * Begins with the word "router," OR
        * Includes "address-family vpnv4," OR
        * Includes "sham-link"
      
          Router# show run | include ^router |address-family vpnv4|sham-link
          router bgp 1
            address-family vpnv4
          router ospf 1 vrf VRFNAME
           area 0 sham-link  192.168.1.1 192.168.100.1
          Router# 
          
      For customers that run versions of IOS that support the section
      modifier, an additional option is available to view the relevant
      sections of the running configuration:
      
          Router# show run | section ^router
          router bgp 1
          [snip]
            address-family vpnv4
          router ospf 1 vrf VRFNAME
           area 0 sham-link  192.168.1.1 192.168.100.1
          [snip]
      
      If certain packets are received by a device that meets the above
      requirements, the input queue of the interface that receives these
      packets can become blocked, which can prohibit additional traffic
      from entering the interface and cause a denial of service condition.
      In addition to a potential blocked interface queue, the device can
      also suffer a memory leak or restart. In the event of a memory leak,
      the device is unable to forward traffic once available memory is
      depleted.
      
      For more information on MPLS VPNs, please reference the following
      document:
      
      http://www.cisco.com/en/US/docs/net_mgmt/vpn_solutions_center/1.1/user/guide/VPN_UG1.html
      
      For more information on OSPF sham-links, please reference the
      following document:
      
      http://www.cisco.com/en/US/docs/ios/12_2t/12_2t8/feature/guide/ospfshmk.html
      
      Identifying a Memory Leak
      +------------------------
      
      This vulnerability can manifest as a leak in the I/O memory pool. The
      following is an example of a system message that indicates an
      exhaustion of the I/O pool:
      
          006029: Aug  10: %SYS-2-MALLOCFAIL: Memory allocation of 808 bytes failed from 0x41613238, alignment 32 
          Pool: I/O Free: 176  Cause: Not enough free memory 
          Alternate Pool: None  Free: 0  Cause: No Alternate pool 
      
      Note that in the above output, the affected memory pool is Pool: I/O,
      and the cause is Cause: Not enough free memory. This output indicates
      that the I/O memory pool has been exhausted.
      
      Additionally, a user with enable-level access can check the device
      through the show buffers command to identify buffer allocation
      failures.
      
          Router#show buffers   
          Buffer elements:   
          496 in free list (500 max allowed)   
          77298300 hits, 0 misses, 0 created   
          
          Public buffer pools:   
          Small buffers, 104 bytes (total 148654, permanent 1024, peak 148654 @ 1d12h):   
          0 in free list (128 min, 2048 max allowed)   
          24688031 hits, 4023203 misses, 0 trims, 147630 created   
          3243434 failures (3182828 no memory) 
      
      The above output shows that buffer allocation failed due to
      insufficient memory.
      
      Identifying a Blocked Interface
      +------------------------------
      
      A symptom of this type of blocked queue is the failure of
      control-plane protocols such as routing protocols (OSPF, Enhanced
      Interior Gateway Routing Protocol (EIGRP), Border Gateway Protocol
      (BGP), Intermediate System to Intermediate System (ISIS), etc.) and
      MPLS TDP/LDP to properly establish connections over an affected
      interface.
      
      In order to identify a blocked input interface, issue the show
      interfaces command, and search for the Input Queue line. The size of
      the input queue can continue to increase. If the current size, which
      is 76 in the example below, is larger than the maximum size (75), the
      input queue is blocked.
      
      It is possible that a device receives a high rate of traffic destined
      to the control plane, and the full queue is only a transient event.
      In order to verify if the interface is actually blocked, shut down
      the interface with the shutdown interface configuration command and
      examine the input queue. If the input queue does not display 0
      packets, the interface is blocked.
      
          Router#show interface ethernet 0/0
          Ethernet0/0 is up, line protocol is up  
            Hardware is AmdP2, address is 0050.500e.f1e0 (bia 0050.500e.f1e0)   
            Internet address is 172.16.1.9/24
            MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
            Encapsulation ARPA, loopback not set, keepalive set (10 sec)
            ARP type: ARPA, ARP Timeout 04:00:00  
            Last input 00:00:41, output 00:00:07, output hang never
            Last clearing of "show interface" counters 00:07:18
            Input queue: 76/75/1091/0 (size/max/drops/flushes); Total output drops: 0  
          
          
          !--- The 76/75 shows that this is blocked
          
      
      Vulnerability Scoring Details
      =============================
      
      Cisco has provided scores for the vulnerabilities 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 
      
      CSCsf12082 - SUP720 facing small buffer leak and crashes
      
        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 - 6.1
      
        Exploitability:         Proof-of-Concept
        Remediation Level:      Official-Fix
        Report Confidence:      Confirmed
      
      Impact
      ======
      
      Exploitation of this vulnerability may result in a blocked interface
      input queue, memory leak, and/or restart of the device. Repeated
      exploitation of this vulnerability may result in an extended denial
      of service.
      
      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  |
      |  Release   |         Releases          |
      |------------+---------------------------|
      |  Affected  | First Fixed | Recommended |
      | 12.0-Based |   Release   |   Release   |
      |  Releases  |             |             |
      |----------------------------------------|
      |    There are no affected 12.0 based    |
      |                releases                |
      |----------------------------------------|
      |  Affected  | First Fixed | Recommended |
      | 12.1-Based |   Release   |   Release   |
      |  Releases  |             |             |
      |----------------------------------------|
      |    There are no affected 12.1 based    |
      |                releases                |
      |----------------------------------------|
      |  Affected  | First Fixed | Recommended |
      | 12.2-Based |   Release   |   Release   |
      |  Releases  |             |             |
      |------------+-------------+-------------|
      | 12.2       | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2B      | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2BC     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2BW     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2BY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2BZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2CX     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2CY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2CZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2DA     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2DD     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2DX     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2EU     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2EW     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2EWA    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2EX     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2EY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2EZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2FX     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2FY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2FZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2IXA    | Vulnerable; |             |
      |            | contact TAC |             |
      |------------+-------------+-------------|
      | 12.2IXB    | Vulnerable; |             |
      |            | contact TAC |             |
      |------------+-------------+-------------|
      | 12.2IXC    | Vulnerable; |             |
      |            | contact TAC |             |
      |------------+-------------+-------------|
      | 12.2IXD    | Vulnerable; |             |
      |            | contact TAC |             |
      |------------+-------------+-------------|
      |            | Vulnerable; | 12.2(18)    |
      |            | migrate to  | IXF;        |
      | 12.2IXE    | any release | Available   |
      |            | in 12.2IXF  | on          |
      |            |             | 31-MAR-2008 |
      |------------+-------------+-------------|
      | 12.2JA     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2JK     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2MB     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2MC     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2S      | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SB     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SBC    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SCA    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SE     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SEA    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SEB    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SEC    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SED    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SEE    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SEF    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SEG    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SG     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SGA    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SL     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SM     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SO     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SRA    | 12.2(33)    | 12.2(33)    |
      |            | SRA4        | SRA7        |
      |------------+-------------+-------------|
      | 12.2SRB    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SRC    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SU     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SV     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SVA    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SVC    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SVD    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SW     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SX     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      |            | Vulnerable; | 12.2(18)    |
      | 12.2SXA    | first fixed | SXF13       |
      |            | in 12.2SXF  |             |
      |------------+-------------+-------------|
      |            | Vulnerable; | 12.2(18)    |
      | 12.2SXB    | first fixed | SXF13       |
      |            | in 12.2SXF  |             |
      |------------+-------------+-------------|
      |            | Vulnerable; | 12.2(18)    |
      | 12.2SXD    | first fixed | SXF13       |
      |            | in 12.2SXF  |             |
      |------------+-------------+-------------|
      |            | Vulnerable; | 12.2(18)    |
      | 12.2SXE    | first fixed | SXF13       |
      |            | in 12.2SXF  |             |
      |------------+-------------+-------------|
      | 12.2SXF    | 12.2(18)    | 12.2(18)    |
      |            | SXF6        | SXF13       |
      |------------+-------------+-------------|
      | 12.2SXH    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2SZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2T      | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2TPC    | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2UZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XA     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XB     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XC     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XD     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XE     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XF     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XG     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XH     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XI     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XJ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XK     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XL     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XM     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XN     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XO     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XQ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XR     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XS     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XT     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XU     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XV     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2XW     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YA     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YB     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YC     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YD     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YE     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YF     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YG     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YH     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YJ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YK     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YL     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YM     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YN     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YO     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YP     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YQ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YR     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YS     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YT     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YU     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YV     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YW     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YX     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2YZ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZA     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZB     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZC     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZD     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZE     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZF     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZG     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZH     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZJ     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZL     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      | 12.2ZP     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      |            | Vulnerable; |             |
      | 12.2ZU     | migrate to  | 12.2(33)    |
      |            | any release | SXH2        |
      |            | in 12.2SXH  |             |
      |------------+-------------+-------------|
      | 12.2ZY     | Not         |             |
      |            | Vulnerable  |             |
      |------------+-------------+-------------|
      |  Affected  | First Fixed | Recommended |
      | 12.3-Based |   Release   |   Release   |
      |  Releases  |             |             |
      |----------------------------------------|
      |    There are no affected 12.3 based    |
      |                releases                |
      |----------------------------------------|
      |  Affected  | First Fixed | Recommended |
      | 12.4-Based |   Release   |   Release   |
      |  Releases  |             |             |
      |----------------------------------------|
      |    There are no affected 12.4 based    |
      |                releases                |
      +----------------------------------------+
      
      Workarounds
      ===========
      
      Once a device interface queue has been exhausted, only a device
      restart can clear OSPF packets in the blocked queue.
      
      Due to the manner in which these packets are processed, the queue
      block occurs prior to the OSPF MD5 check. The OSPF MD5 configuration
      does not protect a device from this vulnerability.
      
      Increasing the Selective Packet Discard (SPD) Headroom
      +-----------------------------------------------------
      
      At the most basic level, the Selective Packet Discard (SPD) provides
      extended buffering for control plane traffic. Known as the SPD
      headroom, this additional queue depth is typically reserved for
      traffic with IP Precedence equal to 6 (such as BGP), the
      Connectionless Network Service (CLNS) based routing protocol
      Intermediate System-to-Intermediate System (IS-IS), OSPF, and Layer 2
      keepalives.
      
      Increasing the SPD headroom provides additional buffering for OSPF
      packets. In the event of a blocked queue, the SPD headroom can be
      increased to allow more control plane traffic buffer space.
      
      More information on SPD can be found in the following white paper:
      
      http://www.cisco.com/web/about/security/intelligence/spd.html
      
      It is possible to expand the queue size to accommodate more packets,
      but packets can still accumulate until the expanded queue is
      exhausted. As a temporary workaround that allows traffic to continue
      to flow, the input hold queue can be increased. Any additional
      malformed packets still fill the queue, but increasing the input
      queue depth can extend the amount of time before the input queue
      fills and traffic ceases flowing. The following example demonstrates
      how to set the input queue size from the default of 75 to the maximum
      of 4096:
      
          Router# configure terminal
          Router(configure)# interface FastEthernet 0/0
          Router(config-if)# hold-queue 4096 in
      
      Removing OSPF Sham-Link Configuration
      +------------------------------------
      
      Because OSPF Sham-Link configuration is required for the
      vulnerability to be present, removing Sham-Link functionality
      eliminates exposure to this vulnerability. In order to remove the
      OSPF Sham-Link configuration from a device, the OSPF configuration
      must be changed on each interface where Sham-Link is configured.
      
      For configuration information on OSPF Sham-Link, please consult the
      following document:
      
      http://www.cisco.com/en/US/docs/ios/12_2t/12_2t8/feature/guide/ospfshmk.html
      
      Cisco IOS Embedded Event Manager
      +-------------------------------
      
      Cisco IOS Embedded Event Manager (EEM) provides event detection and
      reaction capabilities on a Cisco IOS device. It is possible to detect
      blocked interface queues with an EEM policy. EEM can alert
      administrators of blocked interfaces with email, a syslog message, or
      a Simple Network Management Protocol (SNMP) trap.
      
      A sample EEM policy that uses syslog to alert administrators of
      blocked interfaces is available at Cisco Beyond, an online community
      dedicated to EEM. A sample script is available at the following link:
      
      http://forums.cisco.com/eforum/servlet/EEM?page=eem&fn=script&scriptId=981
      
      More information about EEM is available from Cisco.com at the
      following link:
      
      http://www.cisco.com/en/US/products/ps6815/products_ios_protocol_group_home.html
      
      Obtaining Fixed Software
      ========================
      
      Cisco has released free software updates that address this
      vulnerability. 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/products/prod_warranties_item09186a008088e31f.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/warp/public/687/Directory/DirTAC.shtml
      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 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-20080326-queue.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      | 2008-March-26 | 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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