Cisco Security Advisory

Cisco IOS Software IPv6 Virtual Fragmentation Reassembly Denial of Service Vulnerability

Advisory ID: cisco-sa-20130925-ipv6vfr

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ipv6vfr

Revision 1.0

For Public Release 2013 September 25 16:00  UTC (GMT)


Summary

A vulnerability in the implementation of the virtual fragmentation reassembly (VFR) feature for IP version 6 (IPv6) in Cisco IOS Software could allow an unauthenticated, remote attacker to cause an affected device to hang or reload, resulting in a denial of service (DoS) condition.

The vulnerability is due to a race condition while accessing the reassembly queue for IPv6 fragments. An attacker could exploit this vulnerability by sending a crafted stream of valid IPv6 fragments. Repeated exploitation may result in a sustained DoS condition.

Cisco has released free software updates that address this vulnerability. There are no workarounds for this vulnerability.

This advisory is available at the following link:http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ipv6vfr

Note: The September 25, 2013, Cisco IOS Software Security Advisory bundled publication includes eight Cisco Security Advisories. All advisories address vulnerabilities in Cisco IOS Software. Each Cisco IOS Software Security Advisory lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as well as the Cisco IOS Software releases that correct all Cisco IOS Software vulnerabilities in the September 2013 bundled publication.

Individual publication links are in "Cisco Event Response: Semiannual Cisco IOS Software Security Advisory Bundled Publication" at the following link:

http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep13.html

Affected Products

Vulnerable Products

Cisco devices running an affected Cisco IOS Software release are vulnerable if the IPv6 VFR feature is enabled.

The show ipv6 virtual-reassembly | include Interface|drop privileged EXEC command can be used to determine whether the IPv6 VFR feature has been enabled on a Cisco IOS device. The following is the output from the show ipv6 virtual-reassembly | include Interface|drop command executed on a device running Cisco IOS Software that has the IPv6 VFR feature enabled on multiple interfaces:
Router#show ipv6 virtual-reassembly | include Interface|drop
%Interface FastEthernet0/0 [in]
   IPv6 configured drop fragments: ON
%Interface FastEthernet0/1 [in]
   IPv6 configured drop fragments: ON
%Interface Serial0/0/0 [in]
   IPv6 configured drop fragments: ON
%Interface Serial0/0/1 [in]
   IPv6 configured drop fragments: OFF
%Interface FastEthernet0/1 [out]
   IPv6 configured drop fragments: OFF
%Interface Serial0/1/0 [out]
   IPv6 configured drop fragments: ON
Router#

The previous example shows the IPv6 VFR feature enabled both on the ingress direction (displayed as [in] after the interface name) and on the egress direction (displayed as [out] after the interface name).

The IPv6 VFR feature allows the use of a drop-fragments option to the ipv6 virtual-reassembly command. In this configuration, the IPv6 VFR feature will not perform virtual fragmentation reassembly, but will drop the fragments. Devices using the drop-fragments option on every interface configured for IPv6 VFR are not affected by this vulnerability. This vulnerability applies only to those devices that are configured for IPv6 VFR for either ingress or egress traffic that have at least one interface with the drop-fragments option disabled.

The IPv6 VFR feature is not enabled by default.

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 15.0(1)M1 with an installed image name of C3900-UNIVERSALK9-M:

Router> show version 
Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.0(1)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Wed 02-Dec-09 17:17 by prod_rel_team
!--- output truncated 

Additional information about Cisco IOS Software release naming conventions is available in "White Paper: Cisco IOS and NX-OS Software Reference Guide" at http://www.cisco.com/web/about/security/intelligence/ios-ref.html.

Products Confirmed Not Vulnerable

The following products are confirmed not affected by this vulnerability:
  • Cisco IOS XR Software
  • Cisco IOS XE Software
No other Cisco products are currently known to be affected by this vulnerability.

Details

Fragmentation is a process of breaking down an IP datagram into smaller packets that are transmitted over different types of network media. Non-initial fragments of a fragmented IPv6 packet previously passed through other Cisco IOS features without any examination because of the lack of the Layer 4 (L4) header, which is only available on the initial fragment. The IPv6 VFR feature provides the ability to collect the fragments and provide L4 information for other Cisco IOS features.

A vulnerability in the implementation of the virtual fragmentation reassembly (VFR) feature for IP version 6 (IPv6) in Cisco IOS Software could allow an unauthenticated, remote attacker to cause an affected device to hang or reload, resulting in a denial of service (DoS) condition.

The vulnerability is due to a race condition while accessing the reassembly queue for IPv6 fragments. An attacker could exploit this vulnerability by sending a crafted stream of valid IPv6 fragments. Repeated exploitation may result in a sustained DoS condition.

Note: both transit traffic and traffic to the device itself can trigger this vulnerability.

This vulnerability has been documented in Cisco Bug ID
CSCud64812 (registered customers only) and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2013-5474

Vulnerability Scoring Details

Cisco has scored the vulnerability in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this security advisory is in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps organizations determine the urgency and priority of a response.

Cisco has provided a base and temporal score. Customers can also compute environmental scores that help determine the impact of the vulnerability in their own networks.

Cisco has provided additional information regarding CVSS at the following link:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to compute the environmental impact for individual networks at the following link:

http://intellishield.cisco.com/security/alertmanager/cvss

CSCud64812 : Cisco IOS Software IPv6 Virtual Fragmentation Reassembly Denial of Service Vulnerability

Calculate the environmental score of CSCud64812

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed


Impact

Successful exploitation of this vulnerability may cause the affected device to hang or reload, resulting in a DoS condition.

Software Versions and Fixes

When considering software upgrades, customers are advised to consult the Cisco Security Advisories, Responses, and Notices archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.

In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

Cisco IOS Software

Each row of the following Cisco IOS Software table corresponds to a Cisco IOS Software train. If a particular train is vulnerable, the earliest releases that contain the fix are listed in the First Fixed Release column. The First Fixed Release for All Advisories in the September 2013 Bundled Publication column lists the earliest possible releases that correct all the published vulnerabilities in the Cisco IOS Software Security Advisory bundled publication. Cisco recommends upgrading to the latest available release where possible.

The Cisco IOS Software Checker allows customers to search for Cisco Security Advisories that address specific Cisco IOS Software releases. This tool is available on the Cisco Security Intelligence Operations (SIO) portal at http://tools.cisco.com/security/center/selectIOSVersion.x



Major Release      Availability of Repaired Releases
Affected 12.0-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
There are no affected 12.0 based releases
Affected 12.2-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
12.2EX Not vulnerable
Vulnerable; First fixed in Release 15.0SE
12.2EY Not vulnerable
Vulnerable; First fixed in Release 15.2S
12.2EZ Not vulnerable
Releases prior to 12.2(60)EZ2 are vulnerable; Releases 12.2(60)EZ2 and later are not vulnerable. First fixed in Release 15.0SE
12.2IRB Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRC Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRD Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRE Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRF Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2IRG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IRH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IRI Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IXG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2IXH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2MC Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.2MRA Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2MRB Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SB Not vulnerable
12.2(33)SB15
12.2SCA Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCB Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCC Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCD Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCE Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCF Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCG Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.2SCH Not vulnerable
12.2(33)SCH1
12.2SE Not vulnerable
12.2(55)SE8
12.2SEG Not vulnerable
Vulnerable; First fixed in Release 15.0SE
12.2SG Not vulnerable

12.2(53)SG10; available December 2013 *
12.2SGA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SM Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SQ Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SRA Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2SRB Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2SRC Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2SRD Not vulnerable
Vulnerable; First fixed in Release 12.2SRE
12.2SRE Not vulnerable
12.2(33)SRE9
12.2STE Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SV Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SVD Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SVE Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SW Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.2SXF Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SXH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2SXI Not vulnerable
12.2(33)SXI12
12.2SXJ Not vulnerable
12.2(33)SXJ6
12.2SY Not vulnerable
Vulnerable; First fixed in Release 15.0SY
12.2WO Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2XNA Please see Cisco IOS XE Software Availability
Please see Cisco IOS XE Software Availability
12.2XNB Please see Cisco IOS XE Software Availability
Please see Cisco IOS XE Software Availability
12.2XNC Please see Cisco IOS XE Software Availability
Please see Cisco IOS XE Software Availability
12.2XND Please see Cisco IOS XE Software Availability
Please see Cisco IOS XE Software Availability
12.2XNE Please see Cisco IOS XE Software Availability
Please see Cisco IOS XE Software Availability
12.2XNF Please see Cisco IOS XE Software Availability
Please see Cisco IOS XE Software Availability
12.2XO Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.2ZYA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Affected 12.3-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
12.3BC Not vulnerable
Vulnerable; First fixed in Release 12.2SCH
12.3JEC Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3JED Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3JEE Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3JX Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3XI Not vulnerable
Vulnerable; First fixed in Release 12.2SB
12.3XJ Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3XK Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3XL Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3XQ Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3XR Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3XU Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3XW Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3XX Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YD Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YF Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3YG Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YI Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YJ Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3YK Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YM Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YQ Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3YS Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YT Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.3YU Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3YX Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.3YZ Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3ZA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
Affected 12.4-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
12.4 Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4GC Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JA Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4JAL Not vulnerable
Vulnerable; First fixed in Release 12.4JAM
12.4JAM Not vulnerable
12.4(25e)JAM2
12.4JAN Not vulnerable
Not vulnerable
12.4JAX Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4JAZ Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JDA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JDC Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JDD Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JDE Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4JHA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JHB Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JHC Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4JK Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JL Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JX Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4JY Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4JZ Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4MD Not vulnerable
Vulnerable; First fixed in Release 12.4MDB
12.4MDA Vulnerable; migrate to any release in 12.4MD
Releases up to and including 12.4(22)MDA6 are not vulnerable.
Vulnerable; First fixed in Release 12.4MDB
12.4MDB 12.4(24)MDB15
12.4(24)MDB15
12.4MR Releases up to and including 12.4(16)MR are not vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRA Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRB Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4SW Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4T Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XB Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4XC Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XD Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XE Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XF Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XG Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4XJ Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XK Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XL Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XM Not vulnerable
Vulnerable; First fixed in Release 15.1M
12.4XN Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XP Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XQ Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XR Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XT Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XV Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XW Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XY Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4XZ Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4YA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4YB Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4YD Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4YE Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
12.4YG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Affected 15.0-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
15.0EA Not vulnerable
15.0(2)EA1
15.0EB Not vulnerable
Vulnerable; migrate to any release in 15.2E
15.0EC Not vulnerable
Vulnerable; migrate to any release in 15.2E
15.0ED Not vulnerable
Note: Releases prior to 15.0(2)ED1 are vulnerable; Releases 15.0(2)ED1 and later are not vulnerable.
15.0EH Not vulnerable
Not vulnerable
15.0EJ Not vulnerable
Not vulnerable
15.0EX Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0EY Not vulnerable
15.0(2)EY2
15.0EZ Not vulnerable

Only Release 15.0(2)EZ is vulnerable
15.0M Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.0MR Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.0S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Vulnerable; First fixed in Release 15.1S
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SE Not vulnerable
15.0(2)SE4
15.0SG Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SQA Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SQB Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SY Not vulnerable
15.0(1)SY5
15.0XA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.0XO Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Affected 15.1-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
15.1EY Not vulnerable
Vulnerable; First fixed in Release 15.2S
15.1GC Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.1M 15.1(4)M7
15.1(4)M7
15.1MR Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1MRA Not vulnerable
15.1(3)MRA2
15.1S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1(3)S6
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1SG Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1(2)SG1
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1SNG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SNH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SNI Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SVD Not vulnerable
Not vulnerable
15.1SVE Not vulnerable
Not vulnerable
15.1SVF Not vulnerable
Not vulnerable
15.1SY Not vulnerable

15.1(1)SY2; Available on 28-OCT-13
15.1(2)SY
15.1T Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.1XO Not vulnerable
Not vulnerable
Affected 15.2-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
15.2E Not vulnerable
Not vulnerable
15.2GC 15.2(3)GC1
15.2(4)GC
Vulnerable; migrate to any release in 15.4T
15.2JA Not vulnerable
15.2(4)JA1
15.2JAX Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.2JB Not vulnerable
15.2(2)JB2
15.2JN Not vulnerable
Not vulnerable
15.2M 15.2(4)M4
15.2(4)M4
15.2S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.2(4)S4
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.2SA Not vulnerable
15.2(2)SA
15.2SNG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.2SNH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.2SNI Not vulnerable
Vulnerable; First fixed in Release 15.3S
15.2T 15.2(2)T4
15.2(3)T3
15.2(3)T4
Affected 15.3-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2013 Bundled Publication
15.3M Not vulnerable
Not vulnerable
15.3S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.3(2)S2
15.3(3)S
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.3T 15.3(1)T1
15.3(2)T

15.3(1)T2
15.3(2)T1

* Cisco Catalyst 4500 Series Switches with Cisco Catalyst 4500 Supervisor Engines 6-E or 6L-E can migrate to Cisco IOS Software Release 15.1SG.

Cisco IOS XE Software

Cisco IOS XE Software is not affected by the vulnerability that is disclosed in this document.

Cisco IOS XR Software

Cisco IOS XR Software is not affected by the vulnerability that is disclosed in this document.


Workarounds

There are no workarounds for this vulnerability.

Obtaining Fixed Software

Cisco has released free software updates that address the vulnerability described in this advisory. Prior to deploying software, customers are advised to consult their maintenance providers or check the software for feature set compatibility and known issues that are specific to their environments.

Customers may only install and expect support for feature sets they have purchased. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license at http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html.

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, upgrades should be obtained through the Software Navigator on Cisco.com at http://www.cisco.com/cisco/software/navigator.html.

Customers Using Third-Party Support Organizations

Customers with Cisco products that 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 organization for assistance with the appropriate course of action.

The effectiveness of any workaround or fix depends on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Because of the variety of affected products and releases, customers should consult their service providers or support organizations to ensure that any applied workaround or fix is the most appropriate in the intended network before it is deployed.

Customers Without Service Contracts

Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC):

  • +1 800 553 2447 (toll free from within North America)
  • +1 408 526 7209 (toll call from anywhere in the world)
  • e-mail: tac@cisco.com

Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Customers without service contracts should request free upgrades through the TAC.

Refer to Cisco Worldwide Contacts at http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, instructions, and e-mail addresses for support in various languages.

Exploitation and Public Announcements

The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

This vulnerability was discovered by Cisco during 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 Security Intelligence Operations at the following link:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ipv6vfr

Additionally, a text version of this advisory is clear signed with the Cisco PSIRT PGP key and circulated among the following e-mail addresses:

  • cust-security-announce@cisco.com
  • first-bulletins@lists.first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk

Future updates of this advisory, if any, will reside on Cisco.com but may not be announced on mailing lists. Users can monitor this advisory's URL for any updates.


Revision History

Revision 1.0 2013-September-25 Initial public release

Cisco Security Procedures

Complete information about reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco is available on Cisco.com at http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html. This web page includes instructions for press inquiries regarding Cisco Security Advisories. All Cisco Security Advisories are available at http://www.cisco.com/go/psirt.


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