RE: [VulnWatch] iDefense Security Advisory 03.14.07: Trend Micro Antivirus UPX Parsing Kernel Divide by Zero Vulnerability

["Topolski, Leo" <LTopolski () MSA com>]

As stated by the email below, Trend recommends updating to pattern file
4.335.00 or higher. MSA is currently at 4.347.00 on the Trend Scanmail for
Exchange product. Trend's web site also indicates the affected Scan Engine
of v8.300. We are currently running 8.310-1002.

Thanks.

-----Original Message-----
From: iDefense Labs [mailto:labs-no-reply () idefense com] 
Sent: Wednesday, March 14, 2007 12:55 PM
To: vulnwatch () vulnwatch org; full-disclosure () lists grok org uk;
bugtraq () securityfocus com
Subject: [VulnWatch] iDefense Security Advisory 03.14.07: Trend Micro
Antivirus UPX Parsing Kernel Divide by Zero Vulnerability

Trend Micro Antivirus UPX Parsing Kernel Divide by Zero Vulnerability

iDefense Security Advisory 03.14.07
http://labs.idefense.com/intelligence/vulnerabilities/
Mar 14, 2007

I. BACKGROUND

Trend Micro AntiVirus is an virus scanning engine included in a wide array
of products by Trend Micro. Several examples of vulnerable products include
PC-cillin and Internet Security Suite.

http://www.trendmicro.com/en/home/us/home.htm

II. DESCRIPTION

Remote exploitation of a divide by zero error in Trend Micro AntiVirus may
allow attackers to cause a denial of service.

The vulnerability exists in the kernel driver, VsapiNT.sys. This driver is
responsible for scanning various file formats for malicious content. The
code that parses UPX files takes an integer value from an attacker supplied
file and uses it as a divisor. This results in a divide by zero error in
kernel mode. This causes a kernel fault resulting in a blue screen of death
(BSOD).

III. ANALYSIS

Exploitation of this vulnerability results not only in a DOS of the Trend
Micro process, but in an operating system crash.

There are several different attack vectors depending on which product is
being targeted. Someone targeting a home user would need to convince a user
to download a file from a website or an attachment from an email message.
The user would then need to manually scan this file or save it and have the
Trend Micro auto scan process scan it at some later time. If instead a mail
gateway is being targeted this vulnerability can be exploited automatically
by sending a malicious attachment through a gateway that uses Trend Micro to
scan content.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in Trend Micro
AntiVirus version 14.10.1041, engine version 8.320.1003. Previous versions
may also be affected.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VI. VENDOR RESPONSE

"To address this vulnerability, Trend Micro recommends customers to update
to Virus Pattern File 4.335.00 or higher."

For more information, consult the Trend Micro Knowledge Base article at the
link shown below.

http://esupport.trendmicro.com/support/viewxml.do?ContentID=EN-1034587

VII. CVE INFORMATION

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

VIII. DISCLOSURE TIMELINE

02/27/2007  Initial vendor notification
02/27/2007  Initial vendor response
03/14/2007  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php

Free tools, research and upcoming events http://labs.idefense.com/

X. LEGAL NOTICES

Copyright (c) 2007 iDefense, Inc.

Permission is granted for the redistribution of this alert electronically.
It may not be edited in any way without the express written consent of
iDefense. If you wish to reprint the whole or any part of this alert in any
other medium other than electronically, please e-mail
customerservice () idefense com for permission.

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.