Software Engineering Institute

Microsoft Windows comes with an ActiveX component called "ActiveX control for streaming video," which is provided by msvidctl.dll. This component provides a number of Class Identifiers (CLSIDs) that are marked as Safe for Scripting and Safe for Initialization, which means that they can be used by Internet Explorer. The ActiveX controls provided by msvidctl.dll fail to properly handle file input, which can result in stack memory corruption. This can allow the Structured Exception Handler (SEH) to be overwritten, thus allowing subversion of the program execution flow.

By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), an attacker may be able to execute arbitrary code with the privileges of the user.

Microsoft has released an update to address this issue. See Microsoft Security Bulletin MS09-032 for more information.

Disable the vulnerable ActiveX controls

Microsoft Security Advisory (972890) explains how to disable the 45 ActiveX controls provided by msvidctl.dll to mitigate this vulnerability. A Microsoft Fix it application is provided in Microsoft Knowledgebase article 972890 to disable these controls.

Disable ActiveX

Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the "Securing Your Web Browser" document.