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Cisco Security Advisory: Cisco IOS MPLS Forwarding Infrastructure
Denial of Service Vulnerability

Advisory ID: cisco-sa-20080924-mfi

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

Revision 1.0

For Public Release 2008 September 24 1600 UTC (GMT)

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

Summary
======
Cisco IOS Software Multi Protocol Label Switching (MPLS) Forwarding
Infrastructure (MFI) is vulnerable to a Denial of Service (DoS)
attack from specially crafted packets. Only the MFI is affected by
this vulnerability. Older Label Forwarding Information Base (LFIB)
implementation, which is replaced by MFI, is not affected.

Cisco has released free software updates that address this
vulnerability.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20080924-mfi.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-vpn.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
================
Devices that run Cisco IOS software (including those that support
Cisco IOS Software Modularity) and support MFI are affected if they
are configured for MPLS.

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

A device that runs Cisco IOS software and supports MFI will have
mfi_ios in the output of the show subsys command. The following
example shows output from a device that supports MFI:

    Router#show subsys name mfi_ios
                 Class         Version
    mfi_ios      Protocol    1.000.001
    Router#

The following example shows output from a device that is configured
for MPLS:

    Router#show mpls interface
    Interface      IP           Tunnel  BGP Static Operational
    Ethernet0/0    Yes (ldp)    No      No  No     Yes
    Router#

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

     


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

Devices running Cisco IOS software versions that do not include MFI
are not vulnerable.

Devices that are not configured for MPLS are not vulnerable.

Devices that are running Cisco IOS XR software are not vulnerable.

No other Cisco products are currently known to be affected by these
vulnerabilities.

Details 
======
In newer versions of Cisco IOS software, a new packet forwarding
infrastructure was introduced to improve scalability and performance.
This forwarding infrastructure, called MFI, is transparent to the
user. MFI manages MPLS data structures used for forwarding and
replaces the older implementation, Label Forwarding Information Base
(LFIB). Cisco IOS MFI implementation is vulnerable to a DoS attack
from specially crafted packets that are handled in the software path,
including transit packets that are handled in the software path. Such
packets can be sent from the local segment to the interfaces that are
configured for MPLS or via tunnel interfaces that are configured for
MPLS. To target a remote system in an MPLS network, an attacker needs
to have access to the MPLS network through an MPLS-enabled interface.
MPLS packets are dropped on interfaces that are not configured for
MPLS.

Devices that support MFI will have mfi_ios in the output of the show
subsys command. Interfaces that are enabled for MPLS can be seen by
the show mpls interface command.

More information on MFI can be found at the following link:

http://www.cisco.com/en/US/docs/ios/mpls/configuration/guide/mp_lsc_removed.html 

This vulnerability is documented in the Cisco Bug ID CSCsk93241 
and has been assigned Common Vulnerabilities and Exposures (CVE) 
ID CVE-2008-3804.

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 

CSCsk93241 - Chunk memory corruption on LFDp Input Proc

CVSS Base Score - 7.8

        Access Vector          - Network
        Access Complexity      - Low
        Authentication         - None
        Confidentiality Impact - None
        Integrity Impact       - None
        Availability Impact    - Complete

CVSS Temporal Score - 6.4

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

Impact
=====
Successful exploitation of this vulnerability may result in the
reload of the device, leading to a DoS condition.

Software Versions and Fixes
==========================
When considering software upgrades, also consult 
http://www.cisco.com/go/psirt and any subsequent advisories to 
determine exposure and a complete upgrade solution.

In all cases, customers should exercise caution to be certain the
devices to be upgraded contain sufficient memory and that current
hardware and software configurations will continue to be supported
properly by the new release. If the information is not clear, contact
the Cisco Technical Assistance Center (TAC) or your contracted
maintenance provider for assistance.

Each row of the Cisco IOS software table (below) names a Cisco IOS
release train. If a given release train is vulnerable, then the
earliest possible releases that contain the fix (along with the
anticipated date of availability for each, if applicable) are listed
in the "First Fixed Release" column of the table. The "Recommended
Release" column indicates the releases which have fixes for all the
published vulnerabilities at the time of this Advisory. A device
running a release in the given train that is earlier than the release
in a specific column (less than the First Fixed Release) is known to
be vulnerable. Cisco recommends upgrading to a release equal to or
later than the release in the "Recommended Releases" column of the
table.

+-------------------------------------------------------------------+
|   Major    |          Availability of Repaired Releases           |
|  Release   |                                                      |
|------------+------------------------------------------------------|
|  Affected  |                                      |  Recommended  |
| 12.0-Based |         First Fixed Release          |    Release    |
|  Releases  |                                      |               |
|-------------------------------------------------------------------|
| There are no affected 12.0 based releases                         |
|-------------------------------------------------------------------|
|  Affected  |                                      |  Recommended  |
| 12.1-Based |         First Fixed Release          |    Release    |
|  Releases  |                                      |               |
|-------------------------------------------------------------------|
| There are no affected 12.1 based releases                         |
|-------------------------------------------------------------------|
|  Affected  |                                      |  Recommended  |
| 12.2-Based |         First Fixed Release          |    Release    |
|  Releases  |                                      |               |
|------------+--------------------------------------+---------------|
| 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     | 12.2(44)EY; Available on 16-DEC-08   |               |
|------------+--------------------------------------+---------------|
| 12.2EZ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2FX     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2FY     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2FZ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2IRB    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2IXA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2IXB    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2IXC    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 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                       |               |
|------------+--------------------------------------+---------------|
|            | Releases prior to 12.2(22)S are not  |               |
|            | vulnerable.                          |               |
|            |                                      | 12.2(33)SB2;  |
| 12.2S      | Release 12.2(22)S and later and      | Available on  |
|            | prior to 12.2(30)S are vulnerable,   | 26-SEP-08     |
|            |                                      |               |
|            | release 12.2(30)S and later are not  |               |
|            | vulnerable                           |               |
|------------+--------------------------------------+---------------|
|            | 12.2(31)SB12                         | 12.2(33)SB2;  |
| 12.2SB     |                                      | Available on  |
|            | 12.2(33)SB                           | 26-SEP-08     |
|------------+--------------------------------------+---------------|
|            |                                      | 12.2(33)SB2;  |
| 12.2SBC    | Vulnerable; first fixed in 12.2SB    | Available on  |
|            |                                      | 26-SEP-08     |
|------------+--------------------------------------+---------------|
| 12.2SCA    | 12.2(33)SCA1                         | 12.2(33)SCA1  |
|------------+--------------------------------------+---------------|
|            | 12.2(44)SE3; Available on 30-SEP-08  |               |
| 12.2SE     |                                      | 12.2(46)SE    |
|            | 12.2(46)SE                           |               |
|------------+--------------------------------------+---------------|
| 12.2SEA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SEB    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SEC    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SED    | Vulnerable; first fixed in 12.2SE    | 12.2(46)SE    |
|------------+--------------------------------------+---------------|
| 12.2SEE    | Vulnerable; first fixed in 12.2SE    | 12.2(46)SE    |
|------------+--------------------------------------+---------------|
| 12.2SEF    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
|            | Note: Releases prior to 12.2(25)SEG4 |               |
| 12.2SEG    | are vulnerable, release 12.2(25)SEG4 | 12.2(25)SEG6  |
|            | and later are not vulnerable;        |               |
|------------+--------------------------------------+---------------|
| 12.2SG     | 12.2(50)SG; Available on 24-NOV-08   | 12.2(46)SG1   |
|------------+--------------------------------------+---------------|
| 12.2SGA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SL     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SM     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SO     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
|            |                                      | 12.2(33)SRB4  |
| 12.2SRA    | Vulnerable; first fixed in 12.2SRB   |               |
|            |                                      | 12.2(33)SRC2  |
|------------+--------------------------------------+---------------|
| 12.2SRB    | 12.2(33)SRB4                         | 12.2(33)SRB4  |
|------------+--------------------------------------+---------------|
| 12.2SRC    | 12.2(33)SRC1                         | 12.2(33)SRC2  |
|------------+--------------------------------------+---------------|
| 12.2SU     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SV     | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
| 12.2SVA    | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
| 12.2SVC    | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
| 12.2SVD    | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
|            | Note: Releases prior to 12.2(25)SW4  |               |
| 12.2SW     | are vulnerable, release 12.2(25)SW4  | 12.2(25)SW12  |
|            | and later are not vulnerable;        |               |
|------------+--------------------------------------+---------------|
| 12.2SX     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SXA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SXB    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SXD    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SXE    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SXF    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.2SXH    | 12.2(33)SXH3                         | 12.2(33)SXH3  |
|------------+--------------------------------------+---------------|
| 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                       |               |
|------------+--------------------------------------+---------------|
|            |                                      | 12.2(33)SB2;  |
|            |                                      | Available on  |
|            |                                      | 26-SEP-08     |
| 12.2XN     | Vulnerable; first fixed in 12.2SB    |               |
|            |                                      | 12.2(33)SRC2  |
|            |                                      |               |
|            |                                      | 12.2(33)XNA2  |
|------------+--------------------------------------+---------------|
| 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                       |               |
|------------+--------------------------------------+---------------|
|            |                                      | 12.2(33)SB2;  |
| 12.2ZX     | Vulnerable; first fixed in 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  |                                      |               |
|-------------------------------------------------------------------|
| There are no affected 12.3 based releases                         |
|-------------------------------------------------------------------|
|  Affected  |                                      |  Recommended  |
| 12.4-Based |         First Fixed Release          |    Release    |
|  Releases  |                                      |               |
|------------+--------------------------------------+---------------|
| 12.4       | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 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                       |               |
|------------+--------------------------------------+---------------|
| 12.4SW     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4T      | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XB     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XC     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XD     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XE     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XF     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XG     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XJ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XK     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XL     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XM     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XN     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XP     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XQ     | 12.4(15)XQ1                          | 12.4(15)XQ1   |
|------------+--------------------------------------+---------------|
| 12.4XR     | Vulnerable; migrate to any release   | 12.4(15)T7    |
|            | in 12.4T                             |               |
|------------+--------------------------------------+---------------|
| 12.4XT     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XV     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XW     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XY     | 12.4(15)XY4                          | 12.4(15)XY4   |
|------------+--------------------------------------+---------------|
| 12.4XZ     | 12.4(15)XZ1                          | 12.4(15)XZ2   |
|------------+--------------------------------------+---------------|
| 12.4YA     | Not Vulnerable                       |               |
+-------------------------------------------------------------------+

Workarounds
==========
MPLS is normally enabled on physical and logical interfaces that are
shared with other MPLS-enabled devices. It can be disabled on
interfaces where MPLS is not necessary and from which a potential
attack can be launched. This action may help to limit the exposure of
this vulnerability.

If it is not possible to disable MPLS on interfaces from which an
attack can be launched, there are no workarounds to mitigate this
vulnerability.

Obtaining Fixed Software
=======================
Cisco has released free software updates that address these
vulnerabilities. Prior to deploying software, customers should
consult their maintenance provider or check the software for feature
set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets
they have purchased. By installing, downloading, accessing or
otherwise using such software upgrades, customers agree to be bound
by the terms of Cisco's software license terms found at 
http://www.cisco.com/en/US/products/prod_warranties_item09186a008088e31f.html 
or as otherwise set forth at Cisco.com Downloads at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml 

Do not contact psirt@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 found internally.

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-mfi.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.html 
This includes instructions for press inquiries regarding Cisco 
security notices. All Cisco security advisories are available at 
http://www.cisco.com/go/psirt 
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