Cisco Security Advisory: Cisco IOS MPLS VPN May Leak Information

24 Sep 2008

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Hash: SHA1

Cisco Security Advisory: Cisco IOS MPLS VPN May Leak Information

Advisory ID: cisco-sa-20080924-vpn

http://www.cisco.com/warp/public/707/cisco-sa-20080924-vpn.shtml

Revision 1.0

For Public Release 2008 September 24 1600 UTC (GMT)

- ---------------------------------------------------------------------

Summary
=======

Devices running Cisco IOS versions 12.0S, 12.2, 12.3 or 12.4 and
configured for Multiprotocol Label Switching (MPLS) Virtual Private
Networks (VPNs) or VPN Routing and Forwarding Lite (VRF Lite) and
using Border Gateway Protocol (BGP) between Customer Edge (CE) and
Provider Edge (PE) devices may permit information to propagate
between VPNs.

Workarounds are available to help mitigate this vulnerability.

This issue is triggered by a logic error when processing extended
communities on the PE device.

This issue cannot be deterministically exploited by an attacker.

Cisco has released free software updates that address these
vulnerabilities. Workarounds that mitigate these vulnerabilities are
available.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20080924-vpn.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-iosips.shtml
  * 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-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
=================

Products running Cisco IOS versions 12.0S, 12.2, 12.3 or 12.4 and
configured for MPLS VPNs or VRF Lite are potentially affected.

Cisco IOS releases based on 12.1 are not affected.

Vulnerable Products
+------------------

Cisco IOS devices are vulnerable if they are configured for MPLS VPN
or VRF Lite and have a BGP session between the CE and PE devices, and
process extended communities. If a device is configured for MPLS VPN
or VRF Lite the command address-family ipv4 vrf <vrf-name> or
address-family ipv6 vrf <vrf-name> will be present in the device
configuration.

The following shows a command executed on a device configured for
MPLS VPN:

    router#show running-config | include address-family [ipv4|ipv6]

    address-family ipv4 vrf <vrf-name>

The following shows a PE device configured for an IPv4 BGP session
between the PE and the CE:

    router bgp <Local AS>
     address-family ipv4 vrf one
     neighbor <neighbor IP> remote-as < Remote AS>
     neighbor <neighbor IP> activate

To determine the 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 that is running
Cisco IOS release 12.4(11)T2:

    Router#show version
    Cisco IOS Software, 7200 Software (C7200-ADVSECURITYK9-M), Version 12.4(11)T2, RELEASE SOFTWARE (fc4)
    Technical Support: http://www.cisco.com/techsupport
    Copyright (c) 1986-2007 by Cisco Systems, Inc.
    Compiled Tue 01-May-07 04:19 by prod_rel_team

    <output truncated>

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
+--------------------------------

Cisco products not configured for MPLS VPNs or VRF Lite are
unaffected by this vulnerability.

Cisco products that do not run IOS are unaffected by this
vulnerability.

Cisco IOS-XR is not affected.

No other Cisco products are currently known to be affected by this
vulnerability.

Details
=======

MPLS VPNs allow for the creation of 'virtual networks' that customers
can use to segregate traffic into multiple, isolated VPNs. Traffic
within each MPLS VPN is kept separate from the others, thereby
maintaining a virtual private network.

More information on MPLS and MPLS VPNs is available at the following
link:

http://www.cisco.com/en/US/products/ps6557/products_ios_technology_home.html

A bug exists when processing extended communities with MPLS VPNs. If
extended communities are used, MPLS VPN may incorrectly use a
corrupted route target (RT) to forward traffic. If this occurs,
traffic can leak from one MPLS VPN to another.

This vulnerability exists whenever an affected PE device has a BGP
session running in the MPLS VPN Virtual Routing and Forwarding (VRF).
The following two examples of this scenario are the most common:

1) MPLS VPN configuration with BGP running inside the VRF between the
PE and CE devices.

2) MPLS Inter-AS option A with BGP running between the Autonomous
System Border Routers (ASBR).

The mitigation in the Workarounds section filters extended
communities on a PE device, preventing them from being received by
devices configured for MPLS VPN.

This vulnerability was introduced with Cisco bug ID CSCee83237. Cisco
IOS images that do not include CSCee83237 are not vulnerable to this
issue.

It is important to note that this condition cannot be triggered by an
attacker and that the condition does not provide ways to determine
the flow of traffic between VPNs.

This vulnerability is documented in the Cisco Bug ID CSCec12299 
and has been assigned Common Vulnerabilities and Exposures (CVE) ID
CVE-2008-3803.

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 

CVSS Base Score - 5.1

        Access Vector          - Network
        Access Complexity      - High
        Authentication         - None
        Confidentiality Impact - Partial
        Integrity Impact       - Partial
        Availability Impact    - Partial

CVSS Temporal Score - 4.2

        Exploitability          - Functional
        Remediation Level       - Official-Fix
        Report Confidence       - Confirmed

Impact
======

This vulnerability may cause traffic to be improperly routed between
MPLS VPNs, which may lead to a breach of confidentiality.

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   |                                  |                 |
|--------------+----------------------------------+-----------------|
| 12.0         | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0DA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0DB       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0DC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              | 12.0(30)S5                       |                 |
|              |                                  | 12.0(32)S11     |
| 12.0S        | 12.0(31)S3                       |                 |
|              |                                  | 12.0(33)S1      |
|              | 12.0(32)S                        |                 |
|--------------+----------------------------------+-----------------|
| 12.0SC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0SL       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0SP       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0ST       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              |                                  | 12.0(32)S11     |
| 12.0SX       | Vulnerable; first fixed in 12.0S |                 |
|              |                                  | 12.0(33)S1      |
|--------------+----------------------------------+-----------------|
| 12.0SY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              |                                  | 12.0(32)S11     |
| 12.0SZ       | 12.0(30)SZ4                      |                 |
|              |                                  | 12.0(33)S1      |
|--------------+----------------------------------+-----------------|
| 12.0T        | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0W        | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0WC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0WT       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XB       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XD       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XE       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XF       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XG       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XH       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XI       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XJ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XK       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XL       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XM       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XN       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XQ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XR       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XS       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XT       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.0XV       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|   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   |                                  |                 |
|--------------+----------------------------------+-----------------|
| 12.2         | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2B        | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2BC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2BW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2BX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2BY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2BZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2CX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2CY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2CZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2DA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2DD       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2DX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2EW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2EWA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2EX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2EY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2EZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2FX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2FY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2FZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2IRB      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXA      | Vulnerable; migrate to any       | 12.2(18)IXG     |
|              | release in 12.2IXD               |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXB      | Vulnerable; migrate to any       | 12.2(18)IXG     |
|              | release in 12.2IXD               |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXC      | Vulnerable; migrate to any       | 12.2(18)IXG     |
|              | release in 12.2IXD               |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXD      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXE      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXF      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2IXG      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2JA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2JK       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2MB       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2MC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              | 12.2(30)S and later are          | 12.2(33)SB2;    |
| 12.2S        | vulnerable. 12.2(25)S and before | Available on    |
|              | are not vulnerable               | 26-SEP-08       |
|--------------+----------------------------------+-----------------|
|              | 12.2(28)SB5                      |                 |
|              |                                  | 12.2(33)SB2;    |
| 12.2SB       | 12.2(31)SB2                      | Available on    |
|              |                                  | 26-SEP-08       |
|              | 12.2(31)SB3x                     |                 |
|--------------+----------------------------------+-----------------|
|              | Vulnerable; first fixed in       | 12.2(33)SB2;    |
| 12.2SBC      | 12.2SB                           | Available on    |
|              |                                  | 26-SEP-08       |
|--------------+----------------------------------+-----------------|
| 12.2SCA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SE       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SEA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SEB      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SEC      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SED      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SEE      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SEF      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SEG      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SG       | 12.2(37)SG                       | 12.2(46)SG1     |
|--------------+----------------------------------+-----------------|
| 12.2SGA      | 12.2(31)SGA8                     | 12.2(31)SGA8    |
|--------------+----------------------------------+-----------------|
| 12.2SL       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SM       | 12.2(29)SM2                      | 12.2(29)SM4     |
|--------------+----------------------------------+-----------------|
| 12.2SO       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SRA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SRB      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SRC      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SU       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SV       | 12.2(29b)SV1                     |                 |
|--------------+----------------------------------+-----------------|
| 12.2SVA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SVC      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SVD      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SXA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SXB      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SXD      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SXE      | Vulnerable; first fixed in       | 12.2(18)SXF15   |
|              | 12.2SXF                          |                 |
|--------------+----------------------------------+-----------------|
| 12.2SXF      | 12.2(18)SXF3                     | 12.2(18)SXF15   |
|--------------+----------------------------------+-----------------|
| 12.2SXH      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2SZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2T        | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2TPC      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XB       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XD       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XE       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XF       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XG       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XH       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XI       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XJ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XK       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XL       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XM       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XN       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XNA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XNB      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XO       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XQ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XR       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XS       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XT       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XU       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XV       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2XW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YB       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YD       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YE       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YF       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YG       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YH       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YJ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YK       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YL       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YM       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YN       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YO       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YP       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YQ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YR       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YS       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YT       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YU       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YV       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2YZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZB       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZC       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZD       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZE       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZF       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZG       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZH       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZJ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZL       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZP       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZU       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              | Vulnerable; first fixed in       | 12.2(33)SB2;    |
| 12.2ZX       | 12.2SB                           | Available on    |
|              |                                  | 26-SEP-08       |
|--------------+----------------------------------+-----------------|
| 12.2ZY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.2ZYA      | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|   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)       |
|--------------+----------------------------------+-----------------|
| 12.3XQ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XR       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XS       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XU       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XX       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3XZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3YA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3YD       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              | Vulnerable; first fixed in       | 12.3(14)YX13    |
| 12.3YF       | 12.3YX                           |                 |
|              |                                  | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.3YG       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3YH       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3YI       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.3YJ       | Vulnerable; first fixed in 12.4T | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.3YK       | 12.3(11)YK3                      | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
|              |                                  | 12.3(14)YM13;   |
| 12.3YM       | 12.3(14)YM10                     | Available on    |
|              |                                  | 30-SEP-08       |
|--------------+----------------------------------+-----------------|
| 12.3YQ       | Vulnerable; first fixed in 12.4T | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.3YS       | 12.3(11)YS2                      | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.3YT       | Vulnerable; first fixed in 12.4T | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
|              |                                  | 12.4(2)XB10     |
|              | Vulnerable; first fixed in       |                 |
| 12.3YU       | 12.4XB                           | 12.4(9)XG3      |
|              |                                  |                 |
|              |                                  | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.3YX       | 12.3(14)YX7                      | 12.3(14)YX13    |
|--------------+----------------------------------+-----------------|
| 12.3YZ       | 12.3(11)YZ2                      |                 |
|--------------+----------------------------------+-----------------|
| 12.3ZA       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|   Affected   |                                  |   Recommended   |
|  12.4-Based  |       First Fixed Release        |     Release     |
|   Releases   |                                  |                 |
|--------------+----------------------------------+-----------------|
|              | 12.4(10c)                        |                 |
|              |                                  |                 |
|              | 12.4(12a)                        |                 |
|              |                                  |                 |
|              | 12.4(13)                         |                 |
|              |                                  |                 |
| 12.4         | 12.4(3h)                         | 12.4(18c)       |
|              |                                  |                 |
|              | 12.4(5c)                         |                 |
|              |                                  |                 |
|              | 12.4(7e)                         |                 |
|              |                                  |                 |
|              | 12.4(8d)                         |                 |
|--------------+----------------------------------+-----------------|
| 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       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
|              |                                  | 12.4(15)SW2;    |
| 12.4SW       | 12.4(11)SW1                      | Available on    |
|              |                                  | 28-SEP-08       |
|--------------+----------------------------------+-----------------|
|              | 12.4(11)T2                       |                 |
|              |                                  |                 |
|              | 12.4(15)T                        |                 |
|              |                                  |                 |
|              | 12.4(2)T6                        |                 |
| 12.4T        |                                  | 12.4(15)T7      |
|              | 12.4(4)T8                        |                 |
|              |                                  |                 |
|              | 12.4(6)T7                        |                 |
|              |                                  |                 |
|              | 12.4(9)T3                        |                 |
|--------------+----------------------------------+-----------------|
| 12.4XA       | Vulnerable; first fixed in 12.4T | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.4XB       | 12.4(2)XB6                       | 12.4(2)XB10     |
|--------------+----------------------------------+-----------------|
| 12.4XC       | 12.4(4)XC7                       | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
|              |                                  | 12.4(4)XD11;    |
| 12.4XD       | 12.4(4)XD7                       | Available on    |
|              |                                  | 26-SEP-08       |
|--------------+----------------------------------+-----------------|
| 12.4XE       | 12.4(6)XE3                       | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.4XF       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4XG       | 12.4(9)XG2                       | 12.4(9)XG3      |
|--------------+----------------------------------+-----------------|
| 12.4XJ       | 12.4(11)XJ2                      | 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       | Vulnerable; contact TAC          |                 |
|--------------+----------------------------------+-----------------|
| 12.4XQ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4XR       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4XT       | 12.4(6)XT1                       | 12.4(15)T7      |
|--------------+----------------------------------+-----------------|
| 12.4XV       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4XW       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4XY       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4XZ       | Not Vulnerable                   |                 |
|--------------+----------------------------------+-----------------|
| 12.4YA       | Not Vulnerable                   |                 |
+-------------------------------------------------------------------+

Workarounds
===========

Customers running versions of Cisco IOS that support filtering of
extended communities can prevent the corruption of the route target
(RT) by applying a BGP route-map that removes RT entries on inbound
BGP sessions.

The following configuration example applied in the ipv4 address
family of a PE device removes extended communities from the CE
router:

    router bgp <Local AS>
     address-family ipv4 vrf one
     neighbor <neighbor IP>
     remote-as <Remote AS>
     neighbor <neighbor IP>
     activate neighbor <neighbor IP>
     route-map FILTER in exit-address-family
     !
    ip extcommunity-list 100 permit _RT.*_
    !
    !
    route-map FILTER permit 10
     set extcomm-list 100 delete
    !

The following configuration example applied in the ipv6 address
family of a PE device removes extended communities from the CE
router:

    router bgp <Local AS>
     address-family ipv6 vrf one
     neighbor <neighbor IP>
     remote-as <Remote AS>
     neighbor <neighbor IP>
     activate neighbor <neighbor IP>
     route-map FILTER in exit-address-family
    !
    ip extcommunity-list 100 permit _RT.*_
    !
    !
    route-map FILTER permit 10
     set extcomm-list 100 delete
    !

Note: The capability of filtering extended communities is only
available in certain 12.0S and 12.2S based Cisco IOS releases.

BGP session between the PE and the CE needs to cleared to make this
configuration change effective.

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.htm...
or as otherwise set forth at Cisco.com Downloads at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml

Do not contact psirt@cisco.com or security-alert@cisco.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@cisco.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.

This vulnerability cannot be deterministically triggered by an
attacker.

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-vpn.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@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
  * comp.dcom.sys.cisco@newsgate.cisco.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-Sep-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.h...
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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Cisco Security Advisory: Cisco IOS MPLS VPN May Leak Information

Cisco Systems Product Security Incident Response Team