[apops] Cisco Security Advisory: Cisco IOS XR Software IP Packet Vulnera

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  • Subject: [apops] Cisco Security Advisory: Cisco IOS XR Software IP Packet Vulnerability
  • From: Cisco Systems Product Security Incident Response Team <psirt at cisco dot com>
  • Date: Wed, 25 May 2011 11:15:36 -0400
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      Cisco Security Advisory: Cisco IOS XR Software IP Packet
      Advisory ID: cisco-sa-20110525-iosxr
      Revision 1.0
      For Public Release 2011 May 25 1600 UTC (GMT)
      Cisco IOS XR Software Releases 3.8.3, 3.8.4, and 3.9.1 are affected
      by a vulnerability that an unauthenticated, remote user can trigger
      by sending specific IP version 4 (IPv4) packets to or through an
      affected device.
      Successful exploitation could cause the NetIO process to restart.
      Under a sustained attack, the Cisco CRS Modular Services Card (MSC)
      on a Cisco Carrier Routing System (CRS) or a Line Card on a Cisco
      12000 Series Router or Cisco ASR 9000 Series Aggregation Services
      Router will reload.
      Cisco has released free Software Maintenance Units (SMU) that address
      this vulnerability.
      There are no workarounds for this vulnerability.
      This advisory is posted at: 
      Affected Products
      This vulnerability affects any device that is running Cisco IOS XR
      Software Releases 3.8.3, 3.8.4, or 3.9.1 and has an IPv4 address
      configured on one of the interfaces of a Cisco Line Card or Cisco CRS
      Vulnerable Products
      Cisco IOS XR Software Releases 3.8.3, 3.8.4, and 3.9.1 are affected
      when they are running on the following Cisco hardware platforms:
        * Cisco ASR 9000 Series Aggregation Services Routers
        * Cisco Carrier Routing System
        * Cisco XR 12000 Series Routers
      To determine the Cisco IOS XR 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 XR Software by
      displaying text similar to "Cisco IOS XR Software". The software
      version is displayed after the text "Cisco IOS XR Software".
      The following example identifies a Cisco XR 12000 Series Router that
      is running Cisco IOS XR Software Release 3.9.1:
          RP/0/0/CPU0:example#show version
          Wed Dec 15 10:16:47.117 singa
          Cisco IOS XR Software, Version 3.9.1[00]
          Copyright (c) 2010 by Cisco Systems, Inc.
          ROM: System Bootstrap, Version 12.0(20090302:133850) [rtauro-sw30346-33S 1.23dev(0.36)] DEVELOPMENT SOFTWARE
          Copyright (c) 1994-2009 by cisco Systems,  Inc.
          example uptime is 26 minutes
          System image file is "disk0:c12k-os-mbi-3.9.1/mbiprp-rp.vm"
          cisco 12404/PRP (7457) processor with 3145728K bytes of memory.
          7457 processor at 1266Mhz, Revision 1.2
          1 Cisco 12000 Series Performance Route Processor
          1 Cisco 12000 Series SPA Interface Processor-601/501/401
          1 Cisco 12000 4 Port Gigabit Ethernet Controller (4 GigabitEthernet)
          3 Management Ethernet
          5 PLIM_QOS
          8 FastEthernet
          4 GigabitEthernet/IEEE 802.3 interface(s)
          1019k bytes of non-volatile configuration memory.
          982304k bytes of disk0: (Sector size 512 bytes).
          62420k bytes of disk1: (Sector size 512 bytes).
          65536k bytes of Flash internal SIMM (Sector size 256k).
          !--- output truncated
      Products Confirmed Not Vulnerable
      No other releases of Cisco IOS XR Software are affected.
      The following products are not affected by this vulnerability:
        * Cisco IOS Software
        * Cisco IOS XE Software for Cisco ASR 1000 Series Routers
        * Cisco NX-OS Software
      No other Cisco products are currently known to be affected by this
      Cisco IOS XR Software, which is part of the Cisco IOS Software
      family, uses a microkernel-based distributed operating system
      infrastructure. Cisco IOS XR Software runs on the Cisco CRS, Cisco
      12000 Series Routers, and Cisco ASR 9000 Series Aggregation Services
      More information on Cisco IOS XR Software is available at the
      following link:
      This vulnerability affects any device that is running affected
      releases of Cisco IOS XR Software and has an IPv4 address configured
      on one of the interfaces of a Cisco Line Card or Cisco CRS MSC.
      When a Cisco Line Card or Cisco CRS MSC sends a specific IPv4 packet,
      the NetIO process will restart. If the NetIO process is restarted
      several times, the Cisco Line Card or Cisco CRS MSC will reload,
      which could cause a denial of service (DoS) condition for traffic
      that is transiting the affected line cards.
      Although a crash is caused by a packet that originates from the Cisco
      Line Card or Cisco CRS MSC, an unauthenticated, remote user can
      trigger the vulnerability by sending specific IP packets to or
      through the device. In the latter scenario, the Cisco Line Card or
      Cisco CRS MSC will create the specific IPv4 packet response that
      triggers the vulnerability
      This vulnerability is documented in Cisco bug ID CSCth44147 ( 
      registered customers only) and has been assigned CVE ID
      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:
      Cisco has also provided a CVSS calculator to help compute the
      environmental impact for individual networks at
      * CSCth44147: NetIO Process crashes when generating specific IP packet
      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
      Successful exploitation of the vulnerability may result in a reload
      of the Cisco CRS MSC on a Cisco CRS or the line cards on a Cisco
      12000 Series Router or Cisco ASR 9000 Series Aggregation Services
      Router. Repeated exploitation could result in a sustained DoS
      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.
      |   Major   |         Availability of Repaired Releases         |  |
      |  Release  |                                                   |  |
      | Affected  |          |                             |          |  |
      | 3.2.X     |          |                             | First    |  |
      | through   | SMU ID   | SMU NAME                    | Fixed    |  |
      | 3.7.X -   |          |                             | Release  |  |
      | Based     |          |                             |          |  |
      | Releases  |          |                             |          |  |
      | There are no affected 3.2.X through 3.7.X - based releases    |  |
      | Affected  |          |                             | First    |  |
      | 3.8.X     | SMU ID   | SMU NAME                    | Fixed    |  |
      | Based     |          |                             | Release  |  |
      | Releases  |          |                             |          |  |
      | 3.8.0     | Not Vulnerable.                                      |
      | 3.8.1     | Not Vulnerable.                                      |
      | 3.8.2     | Not Vulnerable.                                      |
      |           | CRS:     |                             | No first |  |
      |           | AA04566  | hfr-base-3.8.3.CSCth44147   | fixed    |  |
      |           |          |                             | release; |  |
      |           |----------+-----------------------------|migrate   |--|
      | 3.8.3     | ASR9K    | Not Applicable              | to       |  |
      |           |          |                             | 3.9.X,   |  |
      |           |----------+-----------------------------|4.0.X,    |--|
      |           | XR12000  | Not Applicable              | or       |  |
      |           |          |                             | later.   |  |
      |           | CRS:     |                             | No first |  |
      |           | AA04565  | hfr-base-3.8.4.CSCth44147   | fixed    |  |
      |           |          |                             | release; |  |
      |           |----------+-----------------------------|migrate   |--|
      | 3.8.4     | ASR9K    | Not Applicable              | to       |  |
      |           |          |                             | 3.9.2,   |  |
      |           |----------+-----------------------------|4.X.0,    |--|
      |           | XR12000: |                             | or       |  |
      |           | AA04567  | c12k-base-3.8.4.CSCth44147  | later.   |  |
      |           |          |                             |          |  |
      | Affected  |          |                             | First    |  |
      | 3.9.X     | SMU ID   | SMU NAME                    | Fixed    |  |
      | Based     |          |                             | Release  |  |
      | Releases  |          |                             |          |  |
      | 3.9.0     | Not Vulnerable.                                      |
      |           | CRS:     | hfr-base-3.9.1.CSCth44147   |          |  |
      |           | AA04564  |                             |          |  |
      |           |----------+-----------------------------|          |--|
      | 3.9.1     | ASR9K:   | asr9k-base-3.9.1.CSCth44147 | 3.9.2    |  |
      |           | AA04563  |                             |          |  |
      |           |----------+-----------------------------|          |--|
      |           | XR12000: | c12k-base-3.9.1.CSCth44147  |          |  |
      |           | AA04530  |                             |          |  |
      | 3.9.2     | Not Vulnerable.                                      |
      | Affected  |                                                   |  |
      | 4.0.X -   | There are no affected 4.0.X - based releases      |  |
      | based     |                                                   |  |
      | Releases. |                                                   |  |
      | Affected  |                                                   |  |
      | 4.1.X     | There are no affected 4.1.X based releases.       |  |
      | Based     |                                                   |  |
      | Releases  |                                                   |  |
      There are no workarounds for this vulnerability.
      Using Infrastructure Access Control Lists (iACLs) may help limit the
      attack surface of this vulnerability. Although it is often difficult
      to block traffic that transits a network, it is possible to identify
      traffic that should never be allowed to target infrastructure devices
      and block that traffic at the border of networks. iACLs are a network
      security best practice and should be considered as a long-term
      addition to good network security. Because some packets that may be
      used to exploit this vulnerability could utilize UDP as a transport,
      an attacker could spoof the sender's IP address, which may defeat
      ACLs that permit communication to these ports from trusted IP
      addresses. To provide a better mitigation solution, administrators
      should consider using Unicast Reverse Path Forwarding (Unicast RPF)
      in conjunction with iACLs.
      For more information on iACLs, consult the document "Limit Network
      Access with Access Control Lists" at the following link: 
      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:
      or as otherwise set forth at Cisco.com Downloads at:
      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: 
      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 during the handling of customer
      support calls.
      Status of this Notice: FINAL
      A stand-alone copy or Paraphrase of the text of this document that
      omits the distribution URL in the following section is an
      uncontrolled copy, and may lack important information or contain
      factual errors.
      This advisory is posted on Cisco's worldwide website at :
      In addition to worldwide web posting, a text version of this notice
      is clear-signed with the Cisco PSIRT PGP key and is posted to the
      following e-mail and Usenet news recipients.
        * cust-security-announce at cisco dot com
        * first-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      | 2011-May-25 | public       |
      |          |             | release.     |
      Cisco Security Procedures
      Complete information on reporting security vulnerabilities in Cisco
      products, obtaining assistance with security incidents, and
      registering to receive security information from Cisco, is available
      on Cisco's worldwide website at 
      This includes instructions for press inquiries regarding Cisco security notices.
      All Cisco security advisories are available at http://www.cisco.com/go/psirt
      Copyright 2010-2011 Cisco Systems, Inc. All rights reserved.
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