Date: 02 March 2006
References: ESB-2006.0079
Click here for printable version
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AusCERT Update AU-2006.0009 - [Cisco]
Newer versions also affected by Cisco IOS AAA Command Authorization bypass
vulnerability
2 March 2006
AusCERT Update Summary
----------------------
Product: Cisco IOS version 12.0T and later devices
Publisher: Cisco Systems
Impact: Increased Privileges
Access: Existing Account
CVE Names: CVE-2006-0486
Ref: ESB-2006.0079
Original Bulletin:
http://www.cisco.com/warp/public/707/cisco-response-20060125-aaatcl.shtml
Comment: IOS versions previously thought to be fixed still contain this
vulnerability. Cisco lists the new affected version information
below.
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Cisco Security Notice: Response to AAA Command Authorization by-pass
Document ID: 68840
http://www.cisco.com/warp/public/707/cisco-response-20060125-aaatcl.shtml
Revision 2.0
============
Last Updated 2006 March 01 16:00 UTC (GMT)
For Public Release 2006 January 25 16:00 UTC (GMT)
+--------------------------------------------------------------------
Contents
========
Cisco Response
Additional Information
Status of This Notice: FINAL
Revision History
Cisco Security Procedures
+--------------------------------------------------------------------
Cisco Response
==============
This is an update to the original Cisco Vendor Response posted on
2006 January 25 16:00 UTC at:
http://www.cisco.com/warp/public/707/cisco-response-20060125-aaatcl.shtml
Since the original posting it has been discovered that some versions
of Cisco IOS originally documented as fixed were still affected by
this vulnerability. This new issue is being tracked with Cisco Bug
ID CSCsd28570. An updated Cisco IOS "Software versions and fixes"
table is within. All other relevant information remains unaltered.
A vulnerability exists within Cisco Internetwork Operating System
(IOS) Authentication, Authorization, and Accounting (AAA) command
authorization feature, where command authorization checks are not
performed on commands executed from the Tool Command Language
(Tcl) exec shell. This may allow authenticated users to bypass
command authorization checks in some configurations resulting in
unauthorized privilege escalation.
Devices not running AAA command authorization feature, or do not
support Tcl functionality are not affected by this vulnerability.
We would like to thank Nicolas Fischbach, Senior Manager, Network
Engineering Security of COLT Telecom, for reporting this issue to
Cisco Systems.
We greatly appreciate the opportunity to work with researchers on
security vulnerabilities, and welcome the opportunity to review and
assist in product reports.
Additional Information
======================
Details
+------
Devices that are running AAA command authorization feature and the
IOS has support for the Tcl functionality, may be affected by this
vulnerability.
A device that has Tcl functionality within IOS, will accept the
command "tclsh" and provide a command-line interface (CLI) prompt
back with (tcl) in the CLI prompt.
Example:
router#tclsh
router(tcl)#
If the device does not support Tcl functionality, either an error
message or different output will be displayed.
The (tcl) text within the CLI prompt indicates that the user is
within the Tcl Shell mode.
A system configured for AAA command authorization will have a command
line in "show running-configuration" output which is similar to the
following:
aaa authorization commands <privilege-level> <default|list-name>
<group [group-name]> tacacs+ [additional methods]
Example:
aaa authorization commands 15 default group tacacs+ none
Devices impacted by this vulnerability, will allow users to execute
any IOS EXEC command at the users authenticated privilege level from
within the Tcl shell mode.
This vulnerability is documented in the following bug IDs:
* CSCeh73049 -- tclsh mode bypasses AAA command authorization check
* CSCsd28570 -- tclsh bypass of AAA authorization commands
A separate issue, documented below, exists that exacerbates this
vulnerability. An authenticated user may be placed into Tcl Shell
mode automatically (without the evidence of the (tcl) within the
router prompt), without any intermediate step of manually entering
into Tcl Shell mode via the "tclsh" command, only if a previous user
goes into Tcl Shell mode and terminates the session before leaving
the Tcl Shell mode.
If a privileged user initiates a Tcl Shell and exits the Tcl Shell
mode without issuing the Tcl Shell command "tclquit" then the Tcl
Shell process will remain active and attached to the corresponding
virtual type terminal VTY or teletypewriter (TTY - line). The next
authenticated user that accesses the device over the same line will
have access to the Tcl Shell process, and combined with CSCeh73049
or CSCsd28570 may bypass AAA command authorization checking. This
issue is documented in the following bug ID:
* CSCef77770 -- Type ctrl-c or crtl-z causes tclsh prompt to
disappear
This separate issue is present only in the versions of IOS listed
below:
* 12.3T based trains
* 12.4 based trains
* 12.2(25)S and onward trains
Vulnerable products
+------------------
* All Cisco products that are running Cisco IOS and:
- Have AAA command authorization feature enabled
- The IOS has support for the Tcl functionality
- IOS Version 12.0T or later
Products confirmed not Vulnerable
+--------------------------------
* Products that are not running Cisco IOS are not affected.
* Products running Cisco IOS versions 12.0 Mainline or earlier are
not affected.
* Products running Cisco IOS versions 12.0S are not affected.
* Products that are running Cisco IOS are not affected unless they
are configured for AAA command authorization, and support Tcl
functionality.
* Products that are running Cisco IOS XR are not affected.
No other Cisco products are currently known to be affected by this
vulnerability.
Software versions and fixes
+--------------------------
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).
+---------------------------------------------------------------+
| Major Release | Availability of Repaired Releases |
|--------------------------+------------------------------------|
| Affected 12.0-Based | Rebuild | Maintenance |
| Release | | |
|--------------------------+------------------------------------|
| 12.0T | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.0XH | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.0XK | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.0XL | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.0XN | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.0XR | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| Affected 12.1-Based | Rebuild | Maintenance |
| Release | | |
|--------------------------+------------------------------------|
| 12.1 | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1AA | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1E | 12.1(26)E5 | |
|--------------------------+------------------------------------|
| 12.1EC | Vulnerable; migrate to 12.3BC or |
| | later |
|--------------------------+------------------------------------|
| 12.1EZ | Vulnerable; migrate to 12.1(26)E5 |
| | or later |
|--------------------------+------------------------------------|
| 12.1GA | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1GB | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1T | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XA | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XE | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XH | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XI | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XJ | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XL | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XM | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XP | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XQ | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XS | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XT | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XU | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XV | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XW | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XY | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1XZ | Vulnerable; migrate to 12.2(32) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YA | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YB | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YD | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YE | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YF | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YH | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.1YI | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| Affected 12.2-Based | Rebuild | Maintenance |
| Release | | |
|--------------------------+---------------+--------------------|
| 12.2 | | 12.2(32) |
|--------------------------+------------------------------------|
| 12.2B | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2BW | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2BY | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2DD | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2DX | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2MX | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| | 12.2(14)S16 | |
| |---------------+--------------------|
| | 12.2(18)S11 | |
|12.2S |---------------+--------------------|
| | 12.2(25)S6 | |
| |---------------+--------------------|
| | 12.2(30)S is vulnerable; contact |
| | TAC |
|--------------------------+------------------------------------|
| 12.2SU | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2SW | 12.2(25)SW5 | |
|--------------------------+---------------+--------------------|
| 12.2SXB | 12.2(17d)SXB9 | |
|--------------------------+---------------+--------------------|
| 12.2SXD | 12.2(18)SXD6 | |
|--------------------------+---------------+--------------------|
| 12.2SXE | 12.2(18)SXE3 | |
|--------------------------+------------------------------------|
| 12.2SXF | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2SZ | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2T | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XA | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XB | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XC | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2XD | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XG | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XH | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XJ | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XK | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XL | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XM | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XN | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XQ | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XS | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XT | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XU | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XV | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2XW | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2YB | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2YC | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2YD | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YE | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2YH | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2YK | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YL | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YM | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YN | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YT | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2YU | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YW | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YX | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YY | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2YZ | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2ZB | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2ZC | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2ZD | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2ZE | Vulnerable; migrate to 12.3(16) or |
| | later |
|--------------------------+------------------------------------|
| 12.2ZF | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2ZH | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2ZJ | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2ZL | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.2ZN | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.2ZP | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| Affected 12.3-Based | Rebuild | Maintenance |
| Release | | |
|--------------------------+---------------+--------------------|
| 12.3 | | 12.3(16) |
|--------------------------+------------------------------------|
| 12.3B | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| | 12.3(11)T10; | |
| | available | |
| | 13-March-2006 | |
|12.3T |---------------+--------------------|
| | 12.3(14)T7; | |
| | available | |
| | 3-April-2006 | |
|--------------------------+------------------------------------|
| 12.3XA | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XB | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.3XD | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.3XE | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XF | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.3XG | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XH | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.3XI | vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XJ | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XK | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XM | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.3XQ | Vulnerable; migrate to 12.4(7), |
| | available 14-March-2006 |
|--------------------------+------------------------------------|
| 12.3XR | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XW | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3XY | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| | C828: Vulnerable; migrate to 12.4 |
| | (7), available 14-March-2006 |
| 12.3YA | |
| | SOHO9x, C82x: Vulnerable; contact |
| | TAC |
|--------------------------+------------------------------------|
| 12.3YE | Vulnerable; migrate to 12.3(14)T7, |
| | available 3-April-2006 |
|--------------------------+------------------------------------|
| 12.3YF | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YG | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YH | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YI | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YJ | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YK | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YM | 12.3(14)YM6; available |
| | 26-March-2006 |
|--------------------------+------------------------------------|
| 12.3YQ | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YS | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YT | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YU | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.3YX | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| Affected 12.4-Based | Rebuild | Maintenance |
| Release | | |
|--------------------------+---------------+--------------------|
| | 12.4(3d); | |
| | available | |
| 12.4 | 21-March-2006 | |
| |---------------+--------------------|
| | | 12.4(7); available |
| | | 14-March-2006 |
|--------------------------+------------------------------------|
| 12.4MR | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| | 12.4(2)T4; | |
| | available | |
| | 20-March-2006 | |
| |---------------+--------------------|
| | 12.4(4)T2; | |
| 12.4T | available | |
| | 3-April-2006 | |
| |---------------+--------------------|
| | | 12.4(6)T; |
| | | available |
| | | 13-March-2006 |
|--------------------------+------------------------------------|
| 12.4XA | Vulnerable; contact TAC |
|--------------------------+------------------------------------|
| 12.4XB | Vulnerable; contact TAC |
+---------------------------------------------------------------+
Obtaining Fixed Software
+-----------------------
Cisco has made free software available to address this
vulnerability for affected customers. 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@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 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@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.
* 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.
Workarounds
+----------
The effectiveness of any workaround 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 is the most
appropriate for use in the intended network before it is deployed.
* AAA configuration command checks
Adding IOS configuration command authorization checking with the
global configuration command "aaa authorization config-commands"
forces AAA command authorization to occur within Tcl Shell mode.
Caution: By enabling IOS configuration command authorization all
commands within EXEC configuration mode will be subject to command
authorization checks.
For further information on AAA authorization config-commands please
consult: http://www.cisco.com/univercd/cc/td/doc/product/software/
ios123/123cgcr/secur_r/sec_a1g.htm#wp1086510
* Deny tclsh IOS command within TACACS+ user profile
By ensuring that all user profiles defined within TACACS+ do not have
permission to execute the IOS EXEC command "tclsh" an administrator
can prevent users from gaining additional command privilege
escalation. Seek your vendor's TACACS+ server configuration guides to
ensure this is set correctly.
Caution: This will only be a valid workaround if all users who may
access the device do not have access to "tclsh" command.
A single user who does have access to execute "tclsh" and does not
exit as per the procedure described above, may unknowingly leave a
Tcl Shell process running on one of the VTYs.
* Role Based CLI Views
The Role-Based CLI Access feature allows the network administrator to
define "views," which are a set of operational commands and
configuration capabilities that provide selective or partial access
to Cisco IOS EXEC and configuration (Config) mode commands. Views
restrict user access to Cisco IOS command-line interface (CLI) and
configuration information; that is, a view can define what commands
are accepted and what configuration information is visible. Thus,
network administrators can exercise better control over access to
Cisco networking devices.
For further information on CLI-Views: http://www.cisco.com/univercd/
cc/td/doc/product/software/ios124/124cg/hsec_c/part30/hclivws.htm
Further Information
+-------------------
Cisco IOS introduced the ability to support Tool Command Language
(Tcl) version 7.0 commands as part of Cisco IOS Interactive Voice
Response feature in Cisco IOS version 12.0(6)T and later. See
http://www.cisco.com/univercd/cc/td/doc/product/access/acs_serv/vapp_dev/tclivrpg.htm
for further information.
The Cisco IOS Scripting with Tcl feature provides the ability to run
Tool Command Language (Tcl) version 8.3.4 commands and was introduced
from Cisco IOS version 12.3(2)T. See
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123t/123t_2/gt_tcl.htm
for further information.
Status of This Notice: FINAL
======================
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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.
Revision History
================
+-------------------------------------------------------------------+
| Revision 2.0 | 2006-March-02 | 2.0 Initial Public Release |
|--------------+------------------+---------------------------------|
| Revision 1.1 | 2006-January-25 | Added release 12.2T to software |
| | | table. |
|--------------+------------------+---------------------------------|
| Revision 1.0 | 2006-January-25 | Initial 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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You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
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and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
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organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
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NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
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Contact information for the authors of the original document is included
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Previous advisories and external security bulletins can be retrieved from:
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If you believe that your computer system has been compromised or attacked in
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Incident Reporting Form at:
http://www.auscert.org.au/render.html?it=3192
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
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