Public Vulnerability Reports

Trend Micro TmComm Local Privilege Escalation Vulnerability

02.07.07

BACKGROUND

The Trend Micro AntiVirus scan engine is widely relied upon to provide AntiVirus capabilities to desktop, server, and gateway systems. The engine is licensed to several of Trend Micro's OEM partners. More information is available on Trend Micro's web site at the following URL.

http://www.trendmicro.com/

DESCRIPTION

Local exploitation of an input validation vulnerability within version 1.5.0.1052 of TmComm.sys as included with Trend Micro's AntiVirus engine could allow an attacker execute arbitrary code in kernel context.

This vulnerability specifically exists due to insecure permissions on the \.TmComm DOS device interface. The permissions on this device allows "Everyone" write access. This could allow a locally logged in user to access functionality via IOCTLs which was designed for privileged use only.

Additionally, the IOCTL handlers for this DOS device interface do not validate addresses passed to them. As such, it is possible to overwrite arbitrary memory or execute attacker-supplied code in the context of the kernel (RING 0).

ANALYSIS

Exploitation allows an attacker to elevate privileges by overwriting arbitrary system memory or executing code within kernel context.

DETECTION

iDefense has confirmed the existence of this vulnerability in our vulnerability lab. The configuration at verification time was as follows:

  • Trend Micro's PC-Cillin Internet Security 2007
  • TmComm.sys version 1.5.0.1052
  • VsapiNI.sys (scan engine) version 3.320.0.1003

All products using Trend Micro's scan engine should be considered vulnerable.

WORKAROUND

Removing write permissions for "Everyone" appears to prevent access to the vulnerable code. iDefense confirmed that the virus scanning engine was still able to detect viruses. Although no side effects were witnessed in Lab tests, normal functionality may be hindered.

VENDOR RESPONSE

"To address this vulnerability, Trend Micro recommends to customers to update their Anti-Rootkit Common Module to version 1.600-1052.

Products that are set to Automatic Update will be updated immediately.

Manual Updating can also be performed by using the product’s “Update Now” function."

More information is available in Trend Micro's knowledge base at the link shown below.

http://esupport.trendmicro.com/support/viewxml.do?ContentID=EN-1034432&id=EN-1034432

CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet.

DISCLOSURE TIMELINE

01/17/2007 Initial vendor notification
01/19/2007 Initial vendor response
02/07/2007 Coordinated public disclosure

CREDIT

This vulnerability was reported to iDefense by Rubén Santamarta of reversemode.com.

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LEGAL NOTICES

Copyright © 2006 Verisign, Inc.

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Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.