Vulnerability Note VU#570089

Microsoft HeartbeatCtl ActiveX control buffer overflow

Overview

The Microsoft HeartbeatCtl ActiveX control contains a buffer overflow, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

The Microsoft HeartbeatCtl ActiveX control is used to play multiplayer games on the MSN Games website. The HeartbeatCtl ActiveX control contains a buffer overflow in the handling of the "Host" parameter.

II. Impact

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.

III. Solution

Apply an update

This issue is addressed in Microsoft Security Bulletin MS07-069. This update sets the kill bit for several unsupported versions of the HeartbeatCtl ActiveX control.

Disable the HeartbeatCtl ActiveX control in Internet Explorer

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

{E5D419D6-A846-4514-9FAD-97E826C84822}

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_MACHINESOFTWAREMicrosoftInternet ExplorerActiveX Compatibility{E5D419D6-A846-4514-9FAD-97E826C84822}]
"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.

Systems Affected

Vendor	Status	Date Updated
Microsoft Corporation	Vulnerable	21-Apr-2008

References

http://www.cert.org/tech_tips/securing_browser/
http://www.microsoft.com/technet/security/bulletin/ms07-069.mspx
http://support.microsoft.com/kb/240797

Credit

This vulnerability was reported by Will Dormann of the CERT/CC.

This document was written by Will Dormann.

Other Information

Date Public	12/11/2007
Date First Published	04/21/2008 05:29:07 PM
Date Last Updated	04/21/2008
CERT Advisory
CVE Name	CVE-2007-6255
US-CERT Technical Alerts
Metric	3.90
Document Revision	6