[apops] Cisco Security Advisory: Cisco IOS Software Zone-Based Policy Fi

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  • Subject: [apops] Cisco Security Advisory: Cisco IOS Software Zone-Based Policy Firewall Vulnerability
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  • Date: Wed, 23 Sep 2009 12:15:00 -0400
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      Cisco Security Advisory: Cisco IOS Software Zone-Based Policy
      Firewall Vulnerability
      
      Advisory ID: cisco-sa-20090923-ios-fw
      
      Revision 1.0
      
      For Public Release 2009 September 23
      
      +---------------------------------------------------------------------
      
      Summary
      =======
      
      Cisco IOS® devices that are configured with Cisco IOS Zone-Based
      Policy Firewall Session Initiation Protocol (SIP) inspection are
      vulnerable to denial of service (DoS) attacks when processing a
      specific SIP transit packet. Exploitation of the vulnerability could
      result in a reload of the affected device.
      
      Cisco has released free software updates that address this
      vulnerability.
      
      Workarounds that mitigate this vulnerability are available.
      
      This advisory is posted at:
      
      http://www.cisco.com/warp/public/707/cisco-sa-20090923-ios-fw.shtml
      
      Note: The September 23, 2009, Cisco IOS Security Advisory bundled
      publication includes eleven Security Advisories. Ten of the
      advisories address vulnerabilities in Cisco IOS Software, and one
      advisory addresses a vulnerability in Cisco Unified Communications
      Manager. Each advisory lists the releases that correct the
      vulnerability or vulnerabilities detailed in the advisory. The
      following table lists releases that correct all Cisco IOS Software
      vulnerabilities that have been published on September 23, 2009, or
      earlier.
      
      http://www.cisco.com/warp/public/707/cisco-sa-20090923-bundle.shtml
      
      Individual publication links are in "Cisco Event Response: Semiannual
      Cisco IOS Software Advisory Bundled Publication" at the following
      link:
      
      http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep09.html
      
      Affected Products
      =================
      
      This vulnerability affects a limited number of Cisco IOS Software
      releases. Consult the "Software Versions and Fixes" section of this
      advisory for the details of affected releases.
      
      Only devices that are configured with Cisco IOS Zone-Based Policy
      Firewall SIP inspection (UDP port 5060, TCP ports 5060, and 5061) are
      vulnerable. Cisco IOS devices that are configured with legacy Cisco
      IOS Firewall Support for SIP (context-based access control (CBAC))
      are not vulnerable.
      
      Vulnerable Products
      +------------------
      
      To determine the Cisco IOS Software release that is running on a
      Cisco product, administrators can log in to the device and issue the 
      "show version" command to display the system banner. The system banner
      confirms that the device is running Cisco IOS Software by displaying
      text similar to "Cisco Internetwork Operating System Software" or
      "Cisco IOS Software." The image name displays in parentheses,
      followed by "Version" and the Cisco IOS Software release name. Other
      Cisco devices do not have the "show version" command or may provide
      different output.
      
      The following example identifies a Cisco product that is running
      Cisco IOS Software Release 12.3(26) with an installed image name of
      C2500-IS-L:
      
          Router#show version
          Cisco Internetwork Operating System Software
          IOS (tm) 2500 Software (C2500-IS-L), Version 12.3(26), RELEASE SOFTWARE (fc2)
          Technical Support: http://www.cisco.com/techsupport
          Copyright ©) 1986-2008 by cisco Systems, Inc.
          Compiled Mon 17-Mar-08 14:39 by dchih
          
          <output truncated>
      
      The following example identifies a Cisco product that is running
      Cisco IOS Software Release 12.4(20)T with an installed image name of
      C1841-ADVENTERPRISEK9-M:
      
          Router#show version
          Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 12.4(20)T, RELEASE SOFTWARE (fc3)
          Technical Support: http://www.cisco.com/techsupport
          Copyright ©) 1986-2008 by Cisco Systems, Inc.
          Compiled Thu 10-Jul-08 20:25 by prod_rel_team
          
          <output truncated>
      
      Additional information about Cisco IOS Software release naming
      conventions is available in "White Paper: Cisco IOS Reference Guide"
      at the following link:
      
      http://www.cisco.com/warp/public/620/1.html
      
      The device is vulnerable if the configuration has either a layer 3 or
      layer 7 SIP application-specific policy configured, and these
      policies are applied to any firewall zone. To determine whether the
      device is running a vulnerable configuration, log in to the device
      and issue the command line interface (CLI) command "show policy-map
      type inspect zone-pair | include atch: access|protocol sip". If the
      output contains "Match: protocol sip", the device is vulnerable. If
      the output contains "Match: access-group number", then the device is
      only vulnerable "if", the referenced access list permits the SIP
      protocol (UDP port 5060, or TCP ports 5060 and 5061). The following
      example shows a vulnerable device configured with Cisco IOS
      Zone-Based Policy Firewall SIP inspection:
      
          Router#show policy-map type inspect zone-pair | include atch: access|protocol sip
                Match: protocol sip
          Router#
      
      The following example shows a vulnerable device configured with SIP
      inspection by way of an applied access list:
      
          Router#show policy-map type inspect zone-pair | include atch: access|protocol sip
                Match: access-group 102
          Router#
          Router#show access-list 102
          Extended IP access list 102
              10 permit udp any any eq 5060
              20 permit tcp any any eq 5060
              30 permit tcp any any eq 5061
          Router#
      
      A device that is not configured for SIP inspection or does not
      support this configuration will return either a blank line or an
      error message. The following is an example of a device that supports
      Cisco IOS Firewall but does not have SIP inspection enabled:
      
          Router#show policy-map type inspect zone-pair | include atch: access|protocol sip
          Router#
      
      Products Confirmed Not Vulnerable
      +--------------------------------
      
      No other Cisco products are currently known to be affected by this
      vulnerability. Products confirmed not vulnerable include:
      
        * Cisco PIX 500 Series Firewall
        * Cisco ASA 5500 Series Adaptive Security Appliance
        * Firewall Services Module (FWSM) for Catalyst 6500 Series Switches
          and 7600 Series Routers
        * Virtual Firewall (VFW) application on the multiservice blade
          (MSB) on the Cisco XR 12000 Series Router
        * Cisco ACE Application Control Engine Module
        * Cisco IOS devices NOT configured with Cisco IOS Zone-Based Policy
          Firewall SIP inspection.
        * Cisco IOS devices configured with legacy Cisco IOS Firewall
          Support for SIP (CBAC)
        * Cisco IOS XE Software
        * Cisco IOS XR Software
      
      Details
      =======
      
      Firewalls are networking devices that control access to the network
      assets of an organization. Firewalls are often positioned at the
      entrance points into networks. Cisco IOS software provides a set of
      security features that enable you to configure a simple or elaborate
      firewall policy, according to your particular requirements.
      
      SIP inspection in the Cisco IOS Firewall provides basic SIP inspect
      functionality (SIP packet inspection and pinhole opening) as well as
      protocol conformance and application security.
      
      Cisco IOS Software that is configured with Cisco IOS Zone-Based
      Policy Firewall SIP inspection are vulnerable to a DoS attack when
      processing a specific SIP transit packet. Exploitation of this
      vulnerability will result in a reload of the affected device.
      
      Cisco IOS Zone-Based Policy Firewall SIP inspection was first
      introduced in Cisco IOS Software versions 12.4(15)XZ and 12.4(20)T.
      
      Cisco IOS Firewall CBAC support for SIP inspection by way of the "ip
      inspect name [inspection_name] sip" is not vulnerable. Additional
      information regarding Cisco IOS Firewall CBAC support for SIP
      inspection is available in the document "Firewall Support for SIP" at
      the following link:
      
      http://www.cisco.com/en/US/docs/ios/sec_data_plane/configuration/guide/sec_fwall_sip_supp.html
      
      Additional information regarding Cisco IOS Zone-Based Policy Firewall
      SIP inspection is available in the document "Cisco IOS Firewall: SIP
      Enhancements: ALG and AIC" at the following link:
      
      http://www.cisco.com/en/US/docs/ios/security/configuration/guide/sec_sip_alg_aic.html
      
      This vulnerability is documented in the following Cisco Bug ID: 
      CSCsr18691 and has been assigned the Common Vulnerabilities and Exposures
      (CVE) identifier CVE-2009-2867.
      
      Vulnerability Scoring Details
      =============================
      
      Cisco has provided scores for the vulnerability in this advisory
      based on the Common Vulnerability Scoring System (CVSS). The CVSS
      scoring in this Security Advisory is done in accordance with CVSS
      version 2.0.
      
      CVSS is a standards-based scoring method that conveys vulnerability
      severity and helps determine urgency and priority of response.
      
      Cisco has provided a base and temporal score. Customers can then
      compute environmental scores to assist in determining the impact of
      the vulnerability in individual networks.
      
      Cisco has provided an FAQ to answer additional questions regarding
      CVSS at:
      
      http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html
      
      Cisco has also provided a CVSS calculator to help compute the
      environmental impact for individual networks at:
      
      http://intellishield.cisco.com/security/alertmanager/cvss
      
      CSCsr18691 - Cisco IOS Software Zone-Based Policy Firewall
      
      CVSS Base Score - 7.8
      
      Access Vector           - Network
      Access Complexity       - Low
      Authentication          - None
      Confidentiality Impact  - None
      Integrity Impact        - None
      Availability Impact     - Complete
      
      CVSS Temporal Score - 6.4
      
      Exploitability          - Functional
      Remediation Level       - Official-Fix
      Report Confidence       - Confirmed
      
      Impact
      ======
      
      Successful exploitation of the vulnerability may result in a reload
      of the affected device. Repeated exploit attempts may result in a
      sustained DoS attack.
      
      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 Release  |        Availability of Repaired Releases        |
      |-----------------+-------------------------------------------------|
      |    Affected     |                           |                     |
      |   12.0-Based    |    First Fixed Release    | Recommended Release |
      |    Releases     |                           |                     |
      |-------------------------------------------------------------------|
      | There are no affected 12.0 based releases                         |
      |-------------------------------------------------------------------|
      |    Affected     |                           |                     |
      |   12.1-Based    |    First Fixed Release    | Recommended Release |
      |    Releases     |                           |                     |
      |-------------------------------------------------------------------|
      | There are no affected 12.1 based releases                         |
      |-------------------------------------------------------------------|
      |    Affected     |                           |                     |
      |   12.2-Based    |    First Fixed Release    | Recommended Release |
      |    Releases     |                           |                     |
      |-------------------------------------------------------------------|
      | There are no affected 12.2 based releases                         |
      |-------------------------------------------------------------------|
      |    Affected     |                           |                     |
      |   12.3-Based    |    First Fixed Release    | Recommended Release |
      |    Releases     |                           |                     |
      |-------------------------------------------------------------------|
      | There are no affected 12.3 based releases                         |
      |-------------------------------------------------------------------|
      |    Affected     |                           |                     |
      |   12.4-Based    |    First Fixed Release    | Recommended Release |
      |    Releases     |                           |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4            | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4GC          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JA          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JDA         | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JDC         | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JDD         | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JK          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JL          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JMA         | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JMB         | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4JX          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4MD          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4MDA         | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4MR          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4SW          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      |                 | Releases prior to 12.4    | 12.4(20)T4          |
      |                 | (20)T are not vulnerable; |                     |
      |                 |                           | 12.4(22)T3          |
      | 12.4T           | 12.4(20)T2                |                     |
      |                 |                           | 12.4(24)T2;         |
      |                 | 12.4(22)T1                | Available on        |
      |                 |                           | 23-OCT-2009         |
      |                 | 12.4(24)T                 |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XA          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XB          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XC          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XD          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XE          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XF          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XG          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XJ          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XK          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XL          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XM          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XN          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XP          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XQ          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XR          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XT          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XV          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XW          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4XY          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      |                 |                           | 12.4(20)T4          |
      |                 |                           |                     |
      |                 | Vulnerable; first fixed   | 12.4(22)T3          |
      | 12.4XZ          | in 12.4T                  |                     |
      |                 |                           | 12.4(24)T2;         |
      |                 |                           | Available on        |
      |                 |                           | 23-OCT-2009         |
      |-----------------+---------------------------+---------------------|
      |                 |                           | 12.4(22)T3          |
      |                 | Vulnerable; first fixed   |                     |
      | 12.4YA          | in 12.4T                  | 12.4(24)T2;         |
      |                 |                           | Available on        |
      |                 |                           | 23-OCT-2009         |
      |-----------------+---------------------------+---------------------|
      |                 |                           | 12.4(22)YB4         |
      |                 |                           |                     |
      | 12.4YB          | 12.4(22)YB4               | 12.4(22)YB5;        |
      |                 |                           | Available on        |
      |                 |                           | 19-OCT-2009         |
      |-----------------+---------------------------+---------------------|
      | 12.4YD          | Not Vulnerable            |                     |
      |-----------------+---------------------------+---------------------|
      | 12.4YE          | Not Vulnerable            |                     |
      +-------------------------------------------------------------------+
      
      Workarounds
      ===========
      
      The only workaround for this vulnerability is to disable Cisco IOS
      zone-based policy firewall SIP inspection in the affected device's
      configuration. Disabling SIP inspection will allow the rest of the
      firewall features to continue to function until a software upgrade
      can be implemented. All other firewall features will continue to
      perform normally. Disabling SIP Inspection will vary depending on the
      implementation of the SIP inspection firewall.
      
      Obtaining Fixed Software
      ========================
      
      Cisco has released free software updates that address these
      vulnerabilities. Prior to deploying software, customers should
      consult their maintenance provider or check the software for feature
      set compatibility and known issues specific to their environment.
      
      Customers may only install and expect support for the feature sets
      they have purchased. By installing, downloading, accessing or
      otherwise using such software upgrades, customers agree to be bound
      by the terms of Cisco's software license terms found at:
      
      http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html
      
      or as otherwise set forth at Cisco.com Downloads at:
      
      http://www.cisco.com/public/sw-center/sw-usingswc.shtml
      
      Do not contact psirt at cisco dot com or security-alert at cisco dot com for
      software upgrades.
      
      Customers with Service Contracts
      +-------------------------------
      
      Customers with contracts should obtain upgraded software through
      their regular update channels. For most customers, this means that
      upgrades should be obtained through the Software Center on Cisco's
      worldwide website at http://www.cisco.com.
      
      Customers using Third Party Support Organizations
      +------------------------------------------------
      
      Customers whose Cisco products are provided or maintained through
      prior or existing agreements with third-party support organizations,
      such as Cisco Partners, authorized resellers, or service providers
      should contact that support organization for guidance and assistance
      with the appropriate course of action in regards to this advisory.
      
      The effectiveness of any workaround or fix is dependent on specific
      customer situations, such as product mix, network topology, traffic
      behavior, and organizational mission. Due to the variety of affected
      products and releases, customers should consult with their service
      provider or support organization to ensure any applied workaround or
      fix is the most appropriate for use in the intended network before it
      is deployed.
      
      Customers without Service Contracts
      +----------------------------------
      
      Customers who purchase direct from Cisco but do not hold a Cisco
      service contract, and customers who purchase through third-party
      vendors but are unsuccessful in obtaining fixed software through
      their point of sale should acquire upgrades by contacting the Cisco
      Technical Assistance Center (TAC). TAC contacts are as follows.
      
        * +1 800 553 2447 (toll free from within North America)
        * +1 408 526 7209 (toll call from anywhere in the world)
        * e-mail: tac at cisco dot com
      
      Customers should have their product serial number available and be
      prepared to give the URL of this notice as evidence of entitlement to
      a free upgrade. Free upgrades for non-contract customers must be
      requested through the TAC.
      
      Refer to:
      
      http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html
      
      for additional TAC contact information, including localized telephone
      numbers, and instructions and e-mail addresses for use in various
      languages.
      
      Exploitation and Public Announcements
      =====================================
      
      The Cisco PSIRT is not aware of any public announcements or malicious
      use of the vulnerability described in this advisory.
      
      This vulnerability was discovered by Cisco internal testing.
      
      Status of this Notice: FINAL
      ============================
      
      THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY
      KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF
      MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE
      INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS
      AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS
      DOCUMENT AT ANY TIME.
      
      A stand-alone copy or Paraphrase of the text of this document that
      omits the distribution URL in the following section is an
      uncontrolled copy, and may lack important information or contain
      factual errors.
      
      Distribution
      ============
      
      This advisory is posted on Cisco's worldwide website at :
      
      http://www.cisco.com/warp/public/707/cisco-sa-20090923-ios-fw.shtml
      
      In addition to worldwide web posting, a text version of this notice
      is clear-signed with the Cisco PSIRT PGP key and is posted to the
      following e-mail and Usenet news recipients.
      
        * cust-security-announce at cisco dot com
        * first-bulletins at lists dot first dot org
        * bugtraq at securityfocus dot com
        * vulnwatch at vulnwatch dot org
        * cisco at spot dot colorado dot edu
        * cisco-nsp at puck dot nether dot net
        * full-disclosure at lists.grok dot org dot uk
        * comp.dcom.sys.cisco at newsgate dot cisco dot com
      
      Future updates of this advisory, if any, will be placed on Cisco's
      worldwide website, but may or may not be actively announced on
      mailing lists or newsgroups. Users concerned about this problem are
      encouraged to check the above URL for any updates.
      
      Revision History
      ================
      
      +----------------------------------------+
      | Revision |                   | Initial |
      | 1.0      | 2009-September-23 | public  |
      |          |                   | release |
      +----------------------------------------+
      
      Cisco Security Procedures
      =========================
      
      Complete information on reporting security vulnerabilities in Cisco
      products, obtaining assistance with security incidents, and
      registering to receive security information from Cisco, is available
      on Cisco's worldwide website at:
      
      http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
      
      This includes instructions for press inquiries regarding Cisco security
      notices. All Cisco security advisories are available at:
      
      http://www.cisco.com/go/psirt
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