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Cisco Security Advisory: Cisco Catalyst Enable Password Bypass Vulnerability
Revision 1.0
For Public Release 2003 April 24 08:00 (GMT)

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Contents
Summary
Affected Products
Details
Impact
Software Versions and Fixes
Obtaining Fixed Software
Workarounds
Exploitation and Public Announcements
Status of This Notice
Distribution
Revision History
Cisco Security Procedures


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Summary
Cisco Catalyst software permits unauthorized access to the enable mode in the 7.5(1) 
release. Once initial access is granted, access can be obtained for the higher level 
"enable" mode without a password. This problem is resolved in version 7.6(1). Customers 
with vulnerable releases are urged to upgrade as soon as possible.

This issue is documented in Cisco Bug ID CSCea42030.

This advisory is available at 
http://www.cisco.com/warp/public/707/cisco-sa-20030424-catos.shtml.

Affected Products
All users of Cisco Catalyst 4000, 6000, and 6500 with the Catalyst OS software version 
7.5(1) only.

No other releases of Cisco Catalyst OS software are affected by this vulnerability. 
Additionally, Catalyst hardware running Cisco IOS® software is not affected by this 
vulnerability.

No other Cisco products are affected by this vulnerability.

Details
Anyone who can obtain command line access to an affected switch can bypass password 
authentication to obtain "enable" mode access without knowledge of the "enable" p
assword. 
If local user authentication is enabled, a valid username can be used to gain access to 
the switch without a valid password. This same local user could then enter enable without 
a valid password.

Command line access is provided through the console, telnet access, or ssh access methods; 
http access mode is not affected.

This problem was introduced with the local user authentication feature in software version 
7.5(1), and is corrected in version 7.6(1).

Bug ID
CSCea42030
Impact
This vulnerability permits unauthorized access to the configuration mode and unauthorized 
configuration changes on a Catalyst switch.

Software Versions and Fixes
This vulnerability is repaired in version 7.6(1) which is currently available.

Obtaining Fixed Software
Cisco is offering free software upgrades to remedy this vulnerability for all affected 
customers. Customers may only install and expect support for the feature sets they have 
purchased.
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 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 assistance 
with the upgrade, which should be free of charge.

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)
email: tac@cisco.com.
See 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.

Please 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.

Please do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for 
software 
upgrades

Workarounds
Strictly limiting telnet and/or ssh access to the device will prevent the initial 
connection required to exploit this vulnerability. Telnet and/or ssh access can be 
controlled with the following command set:

set ip permit <address> <mask> telnet
set ip permit <address> <mask> ssh

set ip permit enable
This command set will deny all traffic not specified in the permit statements for each 
protocol.

Additionally, out-of-band management solutions, isolated management VLAN configurations, 
and AAA authentication services can help mitigate this vulnerability by limiting the 
initial access necessary for exploitation.

Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use of the 
vulnerabilities described in this advisory.

Status of This Notice: Draft
This is a draft notice. Although Cisco cannot guarantee the accuracy of all statements in 
this notice, all the facts have been checked to the best of our ability. Cisco does not 
anticipate issuing updated versions of this notice unless there is some material change in 
the facts. Should there be a significant change in the facts, Cisco may update this notice.

Distribution
This notice will be posted on Cisco's worldwide website at 
http://www.cisco.com/warp/public/707/cisco-sa-20030424-catos.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
bugtraq@securityfocus.com
full-disclosure@lists.netsys.com
first-teams@first.org (includes CERT/CC)
cisco@spot.colorado.edu
cisco-nsp@puck.nether.net
comp.dcom.sys.cisco
Various internal Cisco mailing lists
Future updates of this notice, if any, will be placed on Cisco's worldwide web. Users 
concerned about this problem are encouraged to check the URL given above for any updates.

Revision History

Revision 1.0 24-April-2003 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/warp/public/707/sec_incident_response.shtml. 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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This notice is Copyright 2003 by Cisco Systems, Inc. This notice may be redistributed 
freely after the release date given at the top of the text, provided that redistributed 
copies are complete and unmodified, and include all date and version information.