[c-nsp] Cisco Security Advisory: DLSw Vulnerability

Cisco Systems Product Security Incident Response Team psirt at cisco.com
Wed Jan 10 12:08:09 EST 2007


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Cisco Security Advisory: DLSw Vulnerability

Advisory ID: cisco-sa-20070110-dlsw

http://www.cisco.com/warp/public/707/cisco-sa-20070110-dlsw.shtml

Revision 1.0

For Public Release 2007 January 10 1600 UTC (GMT)

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

Summary
=======

A vulnerability exists in the Data-link Switching (DLSw) feature in
Cisco IOS where an invalid value in a DLSw message could result in a
reload of the DLSw device. Successful exploitation of this
vulnerability requires that an attacker be able to establish a DLSw
connection to the device.

There are workarounds available for this vulnerability, as detailed in
the Workarounds section below.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20070110-dlsw.shtml

Affected Products
=================

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

This security advisory applies to all Cisco products that run Cisco IOS
Software versions 11.0 through 12.4 configured for DLSw. A system which
contains the DLSw feature, but does not have it enabled, is not
affected.

A router which is configured for DLSw will have a line in the
configurations defining a local DLSw peer. This definition can be seen
by issuing the command "show running-config" and looking for lines
similar to the following:

    dlsw local-peer peer-id


To determine if DLSw is enabled on your Cisco IOS device, it is also
possible to issue the "show dlsw statistics" command while in enable mode
and look for output similar to:

    Router#show dlsw statistics
    DLSw+ Control Queue Statistics:
     SNA Control Queue (count/max/dropped):     (0/0/0)
     Netbios Control Queue (count/max/dropped): (0/0/0)
     Other Control Queue (count/max/dropped):   (0/100/0)
     Critical Control Queue (count/max):        (0/0)

    DLSw+ Border Peer Caching Statistics:

           0 Border Peer Frames processed
           0 Border frames found Local
           0 Border frames found Remote
           0 Border frames found Group Cache


A device which is not configured for DLSw will simply return to a
command prompt with no output.

A device which does not support the DLSw feature will return output
similar to:

    Router#show dlsw statistics
                  ^
    % Invalid input detected at '^' marker.


Any version of Cisco IOS prior to the versions which will be listed in
the Software Versions and Fixes section below may be vulnerable.

To determine the version of Cisco IOS 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 running IOS release
12.3(6) with an installed image name of C3640-I-M:

    Cisco Internetwork Operating System Software
    IOS (tm) 3600 Software (C3640-I-M), Version 12.3(6), RELEASE SOFTWARE (fc3)


The next example shows a product running IOS release 12.3(11)T3 with an
image name of C3845-ADVIPSERVICESK9-M:

    Cisco IOS Software, 3800 Software (C3845-ADVIPSERVICESK9-M), Version 12.3(11)T3,
     RELEASE SOFTWARE (fc4)
    Technical Support: http://www.cisco.com/techsupport
    Copyright (c) 1986-2005 by Cisco Systems, Inc.


Additional information about Cisco IOS release naming can be found at
http://www.cisco.com/warp/public/620/1.html.

No other Cisco products are currently known to be affected by the
vulnerability addressed in this advisory.

Products Confirmed Not Vulnerable
+--------------------------------

Products confirmed not to be vulnerable include devices which are not
configured for DLSw.

Details
=======

Data-link switching (DLSw) provides a means of transporting IBM Systems
Network Architecture (SNA) and network basic input/output system
(NetBIOS) traffic over an IP network.

Establishing DLSw communications involves several operational stages.

 1. In phase one, DLSw peers establish two TCP connections with each
    other via TCP ports 2065 or 2067. Those TCP connections provide the
    foundation for the DLSw communication.
 2. After a connection is established, the DLSw partners exchange a
    list of supported capabilities in phase two. This helps to ensure
    that the peers use the same options. This is particularly vital
    when the DLSw partners are manufactured by different vendors.
 3. Next, the DLSw partners establish circuits between SNA or NetBIOS
    end systems, and information frames can flow over the circuit.

A vulnerability exists in certain Cisco IOS software releases when
configured for DLSw. After the connection is established, it is
possible for a reload to occur should the device receive an invalid
option during the capabilities exchange.

This vulnerability is documented in Cisco Bug ID CSCsf28840.


Vulnerability Scoring Details
+----------------------------

Cisco is providing scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS).

Cisco will provide a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of the
vulnerability in individual networks.

Cisco PSIRT will set the bias in all cases to normal. Customers are
encouraged to apply the bias parameter when determining the
environmental impact of a particular vulnerability.

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

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.


Cisco Bug IDs:

CSCsf28840

CVSS Base Score: 3.3
    Access Vector: Remote
    Access Complexity: Low
    Authentication: Not Required
    Confidentiality Impact: None
    Integrity Impact: None
    Availability Impact: Complete
    Impact Bias: Normal

CVSS Temporal Score: 2.7
    Exploitability: Functional
    Remediation Level: Official Fix
    Report Confidence: Confirmed


Impact
======

Successful exploitation of the vulnerability may result in a reload of
the device.

Software Version 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) describes a release
train and the platforms or products for which it is intended. If a
given release train is vulnerable, then the earliest possible releases
that contain the fix (the "First Fixed Release") and the anticipated
date of availability for each are listed in the "Rebuild" and
"Maintenance" columns. 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. The release should be
upgraded at least to the indicated release or a later version (greater
than or equal to the First Fixed Release label).

For more information on the terms "Rebuild" and "Maintenance," consult
the following URL: http://www.cisco.com/warp/public/620/1.html.

+------------------------------------------------------------------------------+
|        Major Release        |       Availability of Repaired Releases        |
|-----------------------------+------------------------------------------------|
| Affected 12.0-Based Release | Rebuild             | Maintenance              |
|-----------------------------+------------------------------------------------|
| 12.0                        | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0S                       |                     | 12.0(18)S                |
|-----------------------------+------------------------------------------------|
| 12.0SZ                      | Vulnerable; migrate to 12.0(23)S or later      |
|-----------------------------+------------------------------------------------|
| 12.0T                       | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0WC                      | 12.0(5)WC17;        |                          |
|                             | available 29-Mar-07 |                          |
|-----------------------------+------------------------------------------------|
| 12.0XA                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XC                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XD                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XE                      | Vulnerable; migrate to 12.1(26)E8; available   |
|                             | 20-Jan-07                                      |
|-----------------------------+------------------------------------------------|
| 12.0XG                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XH                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XI                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XJ                      | 12.0(4)XJ5          |                          |
|-----------------------------+------------------------------------------------|
| 12.0XK                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XN                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XQ                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XR                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.0XT                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| Affected 12.1-Based Release | Rebuild             | Maintenance              |
|-----------------------------+------------------------------------------------|
| 12.1                        | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1AA                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
|                             | 12.1(26)E8;         |                          |
|                             | available 20-Jan-07 |                          |
|12.1E                        |---------------------+--------------------------|
|                             | 12.1(27b)E2;        |                          |
|                             | available 25-Jun-07 |                          |
|-----------------------------+------------------------------------------------|
| 12.1EC                      | Vulnerable; migrate to 12.2(4)BC1 or later     |
|-----------------------------+------------------------------------------------|
| 12.1EX                      | Vulnerable; migrate to 12.1(26)E8; available   |
|                             | 20-Jan-07                                      |
|-----------------------------+------------------------------------------------|
| 12.1EZ                      | Vulnerable; migrate to 12.1(26)E8; available   |
|                             | 20-Jan-07                                      |
|-----------------------------+------------------------------------------------|
| 12.1T                       | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XA                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XC                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XD                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XE                      | 12.1(1)XE1          |                          |
|-----------------------------+------------------------------------------------|
| 12.1XG                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1XH                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XI                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XJ                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1XM                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1XP                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1XQ                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1XS                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XT                      | 12.1(3)XT2          |                          |
|-----------------------------+---------------------+--------------------------|
| 12.1XV                      | 12.1(5)XV1          |                          |
|-----------------------------+------------------------------------------------|
| 12.1XW                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XX                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XY                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1XZ                      | Vulnerable; migrate to 12.2(43); available     |
|                             | 8-Mar-07                                       |
|-----------------------------+------------------------------------------------|
| 12.1YA                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1YB                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1YD                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.1YI                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| Affected 12.2-Based Release | Rebuild             | Maintenance              |
|-----------------------------+---------------------+--------------------------|
| 12.2                        |                     | 12.2(43); available      |
|                             |                     | 8-Mar-07                 |
|-----------------------------+------------------------------------------------|
| 12.2B                       | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2BW                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2BY                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2DD                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2DX                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2IXA                     | Vulnerable; migrate to 12.2(18)IXC or later    |
|-----------------------------+------------------------------------------------|
| 12.2IXB                     | Vulnerable; migrate to 12.2(18)IXC or later    |
|-----------------------------+------------------------------------------------|
| 12.2MC                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2S                       |                     | 12.2(30)S                |
|-----------------------------+---------------------+--------------------------|
|                             | 12.2(28)SB6;        |                          |
| 12.2SB                      | available 12-Jan-07 |                          |
|                             |---------------------+--------------------------|
|                             | 12.2(31)SB2         |                          |
|-----------------------------+------------------------------------------------|
| 12.2SBC                     | Vulnerable; migrate to 12.2(31)SB2 or later    |
|-----------------------------+------------------------------------------------|
| 12.2SRA                     | 12.2(33)SRA2        |                          |
|-----------------------------+------------------------------------------------|
| 12.2SU                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2SV                      |                     | 12.2(26)SV               |
|-----------------------------+---------------------+--------------------------|
| 12.2SW                      | 12.2(25)SW9;        |                          |
|                             | available 29-Jan-07 |                          |
|-----------------------------+------------------------------------------------|
| 12.2SX                      | Vulnerable; migrate to 12.2(18)SXE6b;          |
|                             | available 31-Jan-07                            |
|-----------------------------+------------------------------------------------|
| 12.2SXA                     | Vulnerable; migrate to 12.2(18)SXE6b;          |
|                             | available 31-Jan-07                            |
|-----------------------------+------------------------------------------------|
| 12.2SXB                     | Vulnerable; migrate to 12.2(18)SXE6b;          |
|                             | available 31-Jan-07                            |
|-----------------------------+------------------------------------------------|
| 12.2SXD                     | Vulnerable; migrate to 12.2(18)SXE6b;          |
|                             | available 31-Jan-07                            |
|-----------------------------+------------------------------------------------|
| 12.2SXE                     | 12.2(18)SXE6b;      |                          |
|                             | available 31-Jan-07 |                          |
|-----------------------------+---------------------+--------------------------|
| 12.2SXF                     | 12.2(18)SXF8;       |                          |
|                             | available 9-Mar-07  |                          |
|-----------------------------+------------------------------------------------|
| 12.2SY                      | Vulnerable; migrate to 12.2(18)SXE6b;          |
|                             | available 31-Jan-07                            |
|-----------------------------+------------------------------------------------|
| 12.2SZ                      | Vulnerable; migrate to 12.2(30)S or later      |
|-----------------------------+------------------------------------------------|
| 12.2T                       | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2TPC                     | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.2XA                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XB                      | 12.2(2)XB17         |                          |
|-----------------------------+------------------------------------------------|
| 12.2XC                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XD                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XG                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XH                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XJ                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XK                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XL                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XM                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XN                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XQ                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XT                      | Vulnerable; migrate to 12.3(21) or later |     |
|-----------------------------+------------------------------------------------|
| 12.2XU                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XV                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2XW                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YA                      | 12.2(4)YA10         |                          |
|-----------------------------+------------------------------------------------|
| 12.2YB                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YC                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YD                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YE                      | Vulnerable; migrate to 12.2(30)S or later      |
|-----------------------------+------------------------------------------------|
| 12.2YF                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YH                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YJ                      | 12.2(8)YJ1          |                          |
|-----------------------------+------------------------------------------------|
| 12.2YL                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YM                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YN                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YT                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YU                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YV                      | 12.2(11)YV1         |                          |
|-----------------------------+------------------------------------------------|
| 12.2YW                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YX                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YY                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2YZ                      | Vulnerable; migrate to 12.2(30)S or later      |
|-----------------------------+------------------------------------------------|
| 12.2ZA                      | Vulnerable; migrate to 12.2(18)SXE6b;          |
|                             | available 31-Jan-07                            |
|-----------------------------+------------------------------------------------|
| 12.2ZB                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2ZD                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.2ZE                      | Vulnerable; migrate to 12.3(21) or later       |
|-----------------------------+------------------------------------------------|
| 12.2ZF                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2ZH                      | 12.2(13)ZH6         |                          |
|-----------------------------+------------------------------------------------|
| 12.2ZJ                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2ZL                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.2ZN                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.2ZP                      | Migrate to 12.2(20)S7 or later                 |
|-----------------------------+------------------------------------------------|
| 12.2ZU                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.2ZV                      | 12.2(28a)ZV1        |                          |
|-----------------------------+------------------------------------------------|
| 12.2ZW                      | Vulnerable; migrate to 12.2(33)SRB; available  |
|                             | 22-Jan-07                                      |
|-----------------------------+------------------------------------------------|
| 12.2ZX                      |                     | 12.2(28)ZX               |
|-----------------------------+---------------------+--------------------------|
| Affected 12.3-Based Release | Rebuild             | Maintenance              |
|-----------------------------+---------------------+--------------------------|
| 12.3                        |                     | 12.3(21)                 |
|-----------------------------+------------------------------------------------|
| 12.3B                       | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3BW                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3T                       | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XA                      | 12.3(2)XA5          |                          |
|-----------------------------+------------------------------------------------|
| 12.3XB                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XC                      | 12.3(2)XC3          |                          |
|-----------------------------+------------------------------------------------|
| 12.3XD                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XE                      | 12.3(2)XE2          |                          |
|-----------------------------+------------------------------------------------|
| 12.3XF                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XG                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.3XH                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XI                      | 12.3(7)XI8a         |                          |
|-----------------------------+------------------------------------------------|
| 12.3XJ                      | Vulnerable; migrate to 12.4(11)T1; available   |
|                             | 8-Jan-07                                       |
|-----------------------------+------------------------------------------------|
| 12.3XK                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XQ                      | Vulnerable; migrate to 12.4(12) or later       |
|-----------------------------+------------------------------------------------|
| 12.3XR                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.3XU                      | Vulnerable; migrate to 12.4(4)T7 or later      |
|-----------------------------+------------------------------------------------|
| 12.3XW                      | Vulnerable; migrate to 12.4(11)T1; available   |
|                             | 8-Jan-07                                       |
|-----------------------------+------------------------------------------------|
| 12.3XX                      | 12.3(8)XX2          |                          |
|-----------------------------+------------------------------------------------|
| 12.3YF                      | Vulnerable; migrate to 12.4(11)T1; available   |
|                             | 8-Jan-07                                       |
|-----------------------------+------------------------------------------------|
| 12.3YG                      | 12.3(8)YG5          |                          |
|-----------------------------+------------------------------------------------|
| 12.3YH                      | Vulnerable; migrate to 12.4(4)T7 or later      |
|-----------------------------+------------------------------------------------|
| 12.3YI                      | Vulnerable; migrate to 12.4(4)T7 or later      |
|-----------------------------+------------------------------------------------|
| 12.3YJ                      | Vulnerable; migrate to 12.4(6)T6 or later      |
|-----------------------------+------------------------------------------------|
| 12.3YK                      | Vulnerable; migrate to 12.4(4)T7 or later      |
|-----------------------------+------------------------------------------------|
| 12.3YM                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.3YQ                      | Vulnerable; migrate to 12.4(6)T6 or later      |
|-----------------------------+------------------------------------------------|
| 12.3YT                      | Vulnerable; migrate to 12.4(4)T7 or later      |
|-----------------------------+------------------------------------------------|
| 12.3YU                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.3YX                      | Vulnerable; migrate to 12.4(11)T1; available   |
|                             | 8-Jan-07                                       |
|-----------------------------+------------------------------------------------|
| 12.3YZ                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| Affected 12.4-Based Release | Rebuild             | Maintenance              |
|-----------------------------+---------------------+--------------------------|
|                             | 12.4(7d); available |                          |
|                             | 4-Jan-07            |                          |
|12.4                         |---------------------+--------------------------|
|                             | 12.4(8c)            |                          |
|                             |---------------------+--------------------------|
|                             | 12.4(10a)           | 12.4(12)                 |
|-----------------------------+---------------------+--------------------------|
|                             | 12.4(4)T7           |                          |
|                             |---------------------+--------------------------|
|                             | 12.4(6)T6           |                          |
|                             |---------------------+--------------------------|
| 12.4T                       | 12.4(9)T3;          |                          |
|                             | available 12-Mar-07 |                          |
|                             |---------------------+--------------------------|
|                             | 12.4(11)T1;         |                          |
|                             | available 8-Jan-07  |                          |
|-----------------------------+------------------------------------------------|
| 12.4XA                      | Vulnerable; migrate to 12.4(6)T6 or later      |
|-----------------------------+------------------------------------------------|
| 12.4XB                      | Vulnerable; contact TAC                        |
|-----------------------------+------------------------------------------------|
| 12.4XC                      | 12.4(4)XC6;         |                          |
|                             | available 29-Jan-07 |                          |
|-----------------------------+---------------------+--------------------------|
| 12.4XD                      | 12.4(4)XD5          |                          |
|-----------------------------+------------------------------------------------|
| 12.4XE                      | Vulnerable; contact TAC                        |
+------------------------------------------------------------------------------+

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

The effectiveness of any mitigation 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 mitigation or
fix is the most appropriate for use in the intended network before it
is deployed.

Additional mitigations that can be deployed on Cisco devices within the
network are available in the Cisco Applied Intelligence companion
document for this advisory: 

  http://www.cisco.com/warp/public/707/cisco-air-20070110-dlsw.shtml

Configure Explicitly Defined DLSw Peers
+--------------------------------------

If DLSw is configured with no remote peers defined, then it must be
operating in promiscuous mode on one end of the connection. Promiscuous
mode could allow for any device to attempt to establish a DLSw peer
with the router. To prevent malicious connections, DLSw peers may be
explicitly defined with the "dlsw remote-peer" command removing the need
for promiscuous mode.

Obtaining Fixed Software
========================

Cisco will make free software available to address this vulnerability
for affected customers. This advisory will be updated as fixed software
becomes available. 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/public/sw-license-agreement.html,
or as otherwise set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "psirt at cisco.com" or "security-alert at 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 agreement 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 who do not hold a Cisco
service contract and customers who purchase through third-party vendors
but are unsuccessful at obtaining fixed software through their point of
sale should get their upgrades by contacting the Cisco Technical
Assistance Center (TAC). TAC contacts are as follows.

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

Have your product serial number available and give the URL of this
notice as evidence of your 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 special localized
telephone numbers and instructions and e-mail addresses for use in
various languages.

Exploitation and Public Announcements
=====================================

This vulnerability was reported to Cisco by Martyn Ruks of MWR
InfoSecurity and was originally presented at DEFCON in August 2006.

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-20070110-dlsw.shtml

In addition to worldwide web posting, a text version of this notice is
clear-signed with the Cisco PSIRT PGP key and is posted to the
following e-mail and Usenet news recipients.

  * cust-security-announce at cisco.com
  * first-teams at first.org
  * bugtraq at securityfocus.com
  * vulnwatch at vulnwatch.org
  * cisco at spot.colorado.edu
  * cisco-nsp at puck.nether.net
  * full-disclosure at lists.grok.org.uk
  * comp.dcom.sys.cisco at 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      | 2007-January-10 | 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.

- -----------------------------------------------------------------------
All contents are Copyright 1992-2007 Cisco Systems, Inc. All rights
reserved. 
- -----------------------------------------------------------------------

Updated: Jan 10, 2007                                Document ID: 77859

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