Trend Micro SSAPI Long Path Buffer Overflow Vulnerability

iDefense Security Advisory 08.20.07
http://labs.idefense.com/intelligence/vulnerabilities/
Aug 20, 2007

I. BACKGROUND

Trend Micro AntiSpyware is a spyware detection and removal application
designed to help protect home users computers, networks and account
information. More information is available on the vendor's site at the
following URL.

http://us.trendmicro.com/us/products/personal/antispyware/

II. DESCRIPTION

Remote exploitation of buffer overflow vulnerability in Trend Micro
Inc.'s SSAPI Engine could allow attackers to execute arbitrary code
with system level privileges.

Trend Micro products which include the VST functionality are vulnerable
to a stack-based buffer overflow in the vstlib32.dll library. This
overflow is triggered when an attacker creates a file on the local file
system with an overly long path. When vstlib32 receives the
ReadDirectoryChangesW callback notification from the Operating System,
a stack based buffer overflow will occur.

III. ANALYSIS

Exploitation allows attackers to execute arbitrary code with system
level privilege.

Exploitation requires that attackers are able to create a specially
constructed file path on the machine running the Trend Micro product.
This could be the local machine to gain SYSTEM level privileges, or
could be conducted remotely by writing a file to an accessible network
share.

IV. DETECTION

iDefense confirmed the existence of this vulnerability in vstlib32.dll
version 1.2.0.1012. This file is known to be included in several of
Trend Micro's products such as PC-Cillin Internet Security 2007 and
their AntiSpyware products.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VI. VENDOR RESPONSE

Trend Micro has addressed this vulnerability by releasing a HotFix. For
more information consult their Knowledge Base article at the following
URL.

http://esupport.trendmicro.com/support/consumer/search.do?cmd=displayKC&externalId=PUB-en-1035845

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-3873 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

07/12/2007  Initial vendor notification
07/16/2007  Initial vendor response
08/20/2007  Coordinated public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Ismael Briones.

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X. LEGAL NOTICES

Copyright © 2007 iDefense, Inc.

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at the time of publishing based on currently available information. Use
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