Software Engineering Institute

The AddContextRef() and ReleaseContext() functions of the WMI Object Viewer control can be passed an object pointer from an attacker that results in arbitrary code execution. An Internet Explorer user with WBEMSingleView.ocx installed can be exploited by visiting a malicious web page.

An attacker can execute arbitrary code as the user.

We are currently unaware of a practical solution to this problem.

Disable the WMI Object Viewer ActiveX control in Internet Explorer

The vulnerable ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSID:

{2745E5F5-D234-11D0-847A-00C04FD7BB08}

More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{2745E5F5-D234-11D0-847A-00C04FD7BB08}]
"Compatibility Flags"=dword:00000400
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ActiveX Compatibility\{2745E5F5-D234-11D0-847A-00C04FD7BB08}]
"Compatibility Flags"=dword:00000400

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.