Public Vulnerability Reports

Trend Micro SSAPI Long Path Buffer Overflow Vulnerability



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.


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.


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.


iDefense confirmed the existence of this vulnerability in vstlib32.dll version 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.


iDefense is currently unaware of any workarounds for this issue.


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


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 (, which standardizes names for security problems.


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


This vulnerability was reported to iDefense by Ismael Briones.

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Copyright © 2007 Verisign, Inc.

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