[apops] Cisco Security Advisory: Cisco IOS IPS Denial of Service Vulnera

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  • Subject: [apops] Cisco Security Advisory: Cisco IOS IPS Denial of Service Vulnerability
  • From: Cisco Systems Product Security Incident Response Team <psirt at cisco dot com>
  • Date: Wed, 24 Sep 2008 17:50:00 +0200
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      Cisco Security Advisory: Cisco IOS IPS Denial of Service
      Vulnerability
      
      Advisory ID: cisco-sa-20080924-iosips
      
      http://www.cisco.com/warp/public/707/cisco-sa-20080924-iosips.shtml
      
      Revision 1.0
      
      For Public Release 2008 September 24 1600 UTC (GMT)
      
      - ---------------------------------------------------------------------
      
      Summary
      =======
      
      The Cisco IOS Intrusion Prevention System (IPS) feature contains a
      vulnerability in the processing of certain IPS signatures that use
      the SERVICE.DNS engine. This vulnerability may cause a router to
      crash or hang, resulting in a denial of service condition.
      
      Cisco has released free software updates that address this
      vulnerability. There is a workaround for this vulnerability.
      
      Note: This vulnerability is not related in any way to CVE-2008-1447 -
      Cache poisoning attacks. Cisco Systems has published a Cisco Security
      Advisory for that vulnerability, which can be found at 
      http://www.cisco.com/en/US/products/products_security_advisory09186a00809c2168.shtml
      
      This advisory is posted at 
      http://www.cisco.com/warp/public/707/cisco-sa-20080924-iosips.shtml
      
      Note: The September 24, 2008 IOS Advisory bundled publication
      includes twelve Security Advisories. Eleven of the advisories address
      vulnerabilities in Cisco's IOS software, and one advisory addresses
      vulnerabilities in Cisco Unified Communications Manager. Each
      Advisory lists the releases that correct the vulnerability described
      in the Advisory. Please reference the following software table to
      find a release that fixes all published IOS software Advisories as of
      September 24th, 2008:
      
      http://www.cisco.com/warp/public/707/cisco-sa-20080924-bundle.shtml
      
      Individual publication links are listed below:
      
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-ssl.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-sip.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-cucm.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-vpn.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-mfi.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-ipc.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-ubr.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-multicast.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-sccp.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-iosfw.shtml
        * http://www.cisco.com/warp/public/707/cisco-sa-20080924-l2tp.shtml
      
      Affected Products
      =================
      
      Vulnerable Products
      +------------------
      
      Any Cisco IOS device configured with the Cisco IOS IPS feature is
      vulnerable, regardless if it is configured to use the built-in
      signatures or an external signature file. Devices using either
      version 4 or version 5 signatures are affected by this vulnerability.
      
      The Cisco IOS IPS feature is not enabled by default. The command show
      ip ips interfaces can be used to determine if the Cisco IOS IPS
      feature has been configured and applied to any interface on the
      device, as in the following example:
      
          Router#show ip ips interfaces
              Interface Configuration
                Interface FastEthernet0/0
                  Inbound IPS rule is ios-ips-incoming
                  Outgoing IPS rule is not set
                Interface FastEthernet0/1
                  Inbound IPS rule is not set
                  Outgoing IPS rule is ios-ips-outgoing
          Router#
      
      The output of the show ip ips interfaces command when the Cisco IOS
      IPS feature has not been configured is dependent on which Cisco IOS
      release is installed and running on the device. It may be similar to
      the following example:
      
          Router#show ip ips interfaces
      
          Router#
      
      or it may be similar to the following:
      
          Router#show ip ips interfaces
          Interface Configuration
            IPS is not configured on any interface
          Router#
      
      Any version of Cisco IOS prior to the versions which are listed in
      the Software Versions and Fixes section below is vulnerable.
      
      To determine the version of the Cisco IOS software running on a Cisco
      product, log in to the device and issue the show version command to
      display the system banner. Cisco IOS software will identify itself as
      "Internetwork Operating System Software" or simply "IOS". On the next
      line of output, the image name will be displayed between parentheses,
      followed by "Version" and the IOS release name. Other Cisco devices
      will not have the show version command or will give different output.
      
      The following example identifies a Cisco product 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>
          Router#
      
      The next example shows a product running Cisco IOS Software release
      12.4(20)T with an 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>
          Router#
      
      Additional information on the Cisco IOS release naming conventions
      can be found on the document entitled "White Paper: Cisco IOS
      Reference Guide", which is available at 
      http://www.cisco.com/warp/public/620/1.html
      
      Products Confirmed Not Vulnerable
      +--------------------------------
      
      The following Cisco products are confirmed not vulnerable:
      
        * Cisco IOS devices running the Intrusion Detection System feature
        * Cisco ASA Security Appliances running the Intrusion Detection
          System feature
        * Cisco PIX 500 Series Security Appliances running the Intrusion
          Detection System feature
        * Cisco IPS 4200 Sensors
        * Cisco AIP-SSM for ASA 5500 Series Adaptive Security Appliances
        * Cisco Catalyst 6500 Series Intrusion detection System (IDSM-2)
          Services Module
        * Cisco IPS Advanced Integration Module for Integrated Services
          Routers
      
      No other Cisco products are currently known to be affected by this
      vulnerability.
      
      Details
      =======
      
      Cisco IOS Intrusion Prevention System (IPS) is an inline, deep-packet
      inspection feature that effectively mitigates a wide range of network
      attacks. A component of the Cisco IOS Integrated Threat Control
      framework and complemented by Cisco IOS Flexible Packet Matching
      feature, Cisco IOS IPS provides your network with the intelligence to
      accurately identify, classify, and stop or block malicious traffic in
      real time. Additional information on the Cisco IOS IPS feature can be
      found at 
      http://www.cisco.com/en/US/docs/ios/12_3t/12_3t8/feature/guide/gt_fwids.html
      
      Previous to the introduction of the Cisco IOS IPS feature, Cisco IOS
      provided a similar feature, the Cisco IOS Intrusion Detection System
      (IDS). The Cisco IOS IDS feature is not affected by this
      vulnerability. Additional information on the Cisco IOS IDS feature
      can be found at 
      http://www.cisco.com/en/US/docs/ios/12_0t/12_0t5/feature/guide/ios_ids.html
      
      Certain network traffic can trigger IPS signatures on the SERVICE.DNS
      signature engine which may cause the Cisco IOS device to crash or
      hang. This may cause a denial of service that results in disruption
      of network traffic. This vulnerability is documented in Cisco Bug ID
      CSCsq13348.
      
      This vulnerability has been assigned Common Vulnerabilities and
      Exposures (CVE) ID CVE-2008-2739.
      
      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
      
      CSCsq13348 - Watchdog timeout with IPS configured
      
      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 this vulnerability may cause a Cisco IOS
      device configured with the Cisco IOS IPS feature to crash or hang,
      resulting in a denial of service 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                       |               |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3T      | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      | 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                       |               |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3XL     | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3XQ     | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3XR     | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3XS     | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      | 12.3XU     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3XW     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3XX     | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      | 12.3XY     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3XZ     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(15)T7    |
      | 12.3YA     | Vulnerable; first fixed in 12.4      |               |
      |            |                                      | 12.4(18c)     |
      |------------+--------------------------------------+---------------|
      | 12.3YD     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.3YF     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      |            | Releases prior to 12.3(8)YG7 are     |               |
      | 12.3YG     | vulnerable, release 12.3(8)YG7 and   | 12.4(15)T7    |
      |            | later are not vulnerable; first      |               |
      |            | fixed in 12.4T                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3YH     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.3YI     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.3YJ     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3YK     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.3(14)YM13; |
      | 12.3YM     | 12.3(14)YM13; Available on 30-SEP-08 | Available on  |
      |            |                                      | 30-SEP-08     |
      |------------+--------------------------------------+---------------|
      | 12.3YQ     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3YS     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.3YT     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.3YU     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3YX     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.3YZ     | Vulnerable; contact TAC              |               |
      |------------+--------------------------------------+---------------|
      | 12.3ZA     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      |  Affected  |                                      |  Recommended  |
      | 12.4-Based |         First Fixed Release          |    Release    |
      |  Releases  |                                      |               |
      |------------+--------------------------------------+---------------|
      |            | 12.4(18b)                            |               |
      |            |                                      |               |
      | 12.4       | 12.4(19a)                            | 12.4(18c)     |
      |            |                                      |               |
      |            | 12.4(21)                             |               |
      |------------+--------------------------------------+---------------|
      | 12.4JA     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4JK     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4JL     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4JMA    | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4JMB    | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4JMC    | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4JX     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4MD     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4MR     | 12.4(19)MR                           | 12.4(19)MR    |
      |------------+--------------------------------------+---------------|
      | 12.4SW     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      |            | 12.4(15)T6                           |               |
      | 12.4T      |                                      | 12.4(15)T7    |
      |            | 12.4(20)T                            |               |
      |------------+--------------------------------------+---------------|
      | 12.4XA     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.4XB     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XC     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      |            |                                      | 12.4(4)XD11;  |
      | 12.4XD     | 12.4(4)XD11; Available on 26-SEP-08  | Available on  |
      |            |                                      | 26-SEP-08     |
      |------------+--------------------------------------+---------------|
      | 12.4XE     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.4XF     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.4XG     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XJ     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.4XK     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.4XL     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XM     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XN     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XP     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XQ     | Not Vulnerable                       |               |
      |------------+--------------------------------------+---------------|
      | 12.4XT     | Vulnerable; first fixed in 12.4T     | 12.4(15)T7    |
      |------------+--------------------------------------+---------------|
      | 12.4XV     | Vulnerable; contact TAC              |               |
      |------------+--------------------------------------+---------------|
      | 12.4XW     | 12.4(11)XW9                          | 12.4(11)XW9   |
      |------------+--------------------------------------+---------------|
      | 12.4XY     | 12.4(15)XY4                          | 12.4(15)XY4   |
      |------------+--------------------------------------+---------------|
      | 12.4XZ     | 12.4(15)XZ2                          | 12.4(15)XZ2   |
      |------------+--------------------------------------+---------------|
      | 12.4YA     | 12.4(20)YA1                          | 12.4(20)YA1   |
      +-------------------------------------------------------------------+
      
      Workarounds
      ===========
      
      The workaround consists of adding an Access Control List (ACL) to
      every Cisco IOS IPS policy configured on the device so that traffic
      destined to ports 53/udp or 53/tcp is not inspected by the Cisco IOS
      IPS feature. The following ACL would need to be added to the device
      configuration:
      
          ! deny inspection of traffic with a destination port of 53/udp
          access-list 177 deny   udp any any eq 53
          ! deny inspection of traffic with a destination port of 53/tcp
          access-list 177 deny   tcp any any eq 53
          ! allow all other traffic to be inspected
          access-list 177 permit ip any any
      
      Every instance of a Cisco IOS IPS policy on the device would then
      need to be modified in order to reference the previous ACL. In order
      to determine which Cisco IOS IPS policies are configured on the
      device, execute the command show running-config | include ip ips name
      as in the following example:
      
          Router#show running-config | include ip ips name
          ip ips name ios-ips-incoming
          ip ips name ios-ips-outgoing
          Router#
      
      In the previous example, two Cisco IOS IPS policies are configured on
      the device. The following example shows the addition of an ACL to
      each one of the Cisco IOS IPS policies previously identified:
      
          Router#configure terminal
          Enter configuration commands, one per line.  End with CNTL/Z.
          Router(config)#ip ips name ios-ips-incoming list 177
          Router(config)#ip ips name ios-ips-outgoing list 177
          Router(config)#end
          Router#
      
      As a verification step, the command show ip ips interfaces can be
      executed again to verify the ACL has been properly attached to each
      one of the Cisco IOS IPS policies:
      
          Router#show ip ips interfaces
              Interface Configuration
                Interface FastEthernet0/0
                  Inbound IPS rule is ios-ips-incoming
              acl list 177
                  Outgoing IPS rule is not set
                Interface FastEthernet0/1
                  Inbound IPS rule is not set
                  Outgoing IPS rule is ios-ips-outgoing
              acl list 177
          Router#
      
      Note: Disabling or deleting individual or all signatures using the
      SERVICE.DNS engine of the Cisco IOS IPS feature is not a recommended
      workaround. The previous workaround is the only Cisco-recommended
      workaround for this vulnerability.
      
      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/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-20080924-iosips.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      | 2008-September-24 | 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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