Home Programs Emergency management Response CCIRC Analytical releases2 AV06-033: Cisco CatOS and Cisco IOS VLAN Trunking Protocol remote command execution vulnerability

Cisco CatOS and Cisco IOS VLAN Trunking Protocol remote command execution vulnerability

Number: AV06-033
Date: 14 September 2006

Purpose

The purpose of this advisory is to bring attention to a vulnerability has been identified in Cisco CatOS and Cisco IOS.

Assessment

- Cisco CatOS

A vulnerability has been identified in Cisco CatOS, which could be exploited by attackers to execute arbitrary commands or cause a denial of service. This flaw is due to a buffer overflow error in the VTP feature when processing a summary advertisement received on a trunk enabled port with a Type-Length-Value (TLV) containing an overly long VLAN name (more than 100 characters).

This vulnerability affects Cisco CatOS (with VTP Operating Mode as "server" or "client").

- Cisco IOS

Multiple vulnerabilities have been identified in Cisco IOS, which could be exploited by attackers to execute arbitrary commands or cause a denial of service.

The first issue is due to an error in the VLAN Trunking Protocol (VTP) feature that does not properly handle specially crafted summary packets received on a trunk enabled port, which could be exploited by attackers on the local network segment to cause a software reset.

The second flaw is due to a buffer overflow error in the VTP feature when processing a summary advertisement received on a trunk enabled port with a Type-Length-Value (TLV) element containing an overly long VLAN name (more than 100 characters), which could be exploited by attackers to cause a denial of service or execute arbitrary commands.

The third flaw is due to an integer wrap in the VTP feature when handling a specially crafted configuration revision, which could be exploited by attackers to cause certain changes to the VLAN database to not be properly propagated throughout the VTP domain.

This vulnerability affects Cisco IOS versions 12.x and prior (with VTP Operating Mode as "server" or "client").

Suggested action

PSEPC recommends that administrators test and apply recommended fixes, and set a VTP domain password to the VTP domain.

For more information and instructions, please refer to:
http://www.cisco.com/warp/public/707/cisco-sr-20060913-vtp.shtml

Note to readers

Canadian Cyber Incident Response Centre (CCIRC) collects information related to cyber threats to, and incidents involving, Canadian critical infrastructure. This allows us to monitor and analyze threats and to issue alerts, advisories and other information products. To report threats or incidents, please contact the Government Operations Centre (GOC) at (613) 991-7000 or goc-cog@psepc.gc.ca by e-mail.

Unauthorized use of computer systems and mischief in relation to data are serious Criminal Code offences in Canada. Any suspected criminal activity should be reported to local law enforcement organizations. The Royal Canadian Mounted Police (RCMP) National Operations Centre (N.O.C.) provides a 24/7 service to receive such reports or to redirect callers to local law enforcement organizations. The N.O.C. can be reached at (613) 993-4460. National security concerns should be reported to the Canadian Security Intelligence Service (CSIS) at (613) 993-9620.

For urgent matters or to report any incidents, please contact the Government Operations Centre at:

Phone: (613) 991-7000
Fax: (613) 996-0995
Secure Fax: (613) 991-7094
Email: goc-cog@psepc.gc.ca

For general information on critical infrastructure protection and emergency preparedness, please contact PSEPC's Public Affairs division at:

Telephone: (613) 944-4875 or 1-800-830-3118
Fax: (613) 998-9589
E-mail: communications@psepc.gc.ca