US-Cert — ActiveX controls built with Microsoft ATL fail to properly handle initialization data
ActiveX controls that are built using a Microsoft ATL template may fail to properly handle initialization data, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.
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.
Apply an update
This vulnerability has been addressed in the update for Internet Explorer provided in Microsoft Security Bulletin MS09-034. This update helps prevent ActiveX controls that were built with the vulnerable ATL versions from being initialized with unsafe data patterns in Internet Explorer. This also includes techniques that can be used to bypass the kill bit in Internet Explorer.
Update and recompile ActiveX controls
Developers who have created ActiveX controls using Microsoft ATL should install the update for Microsoft Security Bulletin MS09-035 and recompile the ActiveX controls. This will cause the controls to use an updated ATL version that addresses these vulnerabilities.
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.alert, computers, Internet, Microsoft, security