Microsoft Office Web Components ActiveX Control Stack Buffer Overflow Code Execution Vulnerability



Date Discovered

August 11, 2009


The Microsoft Office Web Components ActiveX control is prone to a remote stack-based buffer-overflow vulnerability. An attacker could exploit this issue by enticing a victim to visit a maliciously crafted webpage. Successful exploits will allow the attacker to execute arbitrary code within the context of the affected application that uses the ActiveX control (typically Internet Explorer). Failed exploit attempts will result in a denial-of-service condition.

Technologies Affected

  • Microsoft BizTalk Server 2002 Developer Edition
  • Microsoft BizTalk Server 2002 Developer Edition
  • Microsoft BizTalk Server 2002 Enterprise Edition
  • Microsoft Biztalk Server 2002 Partner Edition
  • Microsoft Biztalk Server 2002 Partner Edition
  • Microsoft Office 2000
  • Microsoft Office 2000 SP1
  • Microsoft Office 2000 SP2
  • Microsoft Office 2000 SP3
  • Microsoft Office 2000 Web Components SP3
  • Microsoft Office XP
  • Microsoft Office XP SP1
  • Microsoft Office XP SP2
  • Microsoft Office XP SP3
  • Microsoft Office XP Web Components SP3
  • Microsoft Visual Studio .NET 2003
  • Microsoft Visual Studio .NET 2003 SP1


Run all software as a nonprivileged user with minimal access rights.
To mitigate the impact of a successful exploit, run the affected application as a user with minimal access rights.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of suspicious or anomalous activity. This may help detect malicious actions that an attacker may take after successfully exploiting vulnerabilities in applications. Review all applicable logs regularly.

Do not follow links provided by unknown or untrusted sources.
Never accept files or follow links from untrusted or unknown sources because they may be malicious in nature.

Set web browser security to disable the execution of script code or active content.
Since a successful exploit of this issue requires malicious code to execute in web clients, consider disabling support for script code and active content within the client browser. Note that this mitigation tactic might adversely affect legitimate websites that rely on the execution of browser-based script code.

Implement multiple redundant layers of security.
Memory-protection schemes (such as nonexecutable stack and heap configurations and randomly mapped memory segments) will complicate exploits of memory-corruption vulnerabilities.

The vendor has released an advisory and fixes. Please see the references for details.



Sean Larsson of VeriSign iDefense Labs

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