Vulnerability Note VU#983249

Corel / Micrografx ActiveCGM Browser ActiveX control buffer overflows

Overview

The Corel / Micrografx ActiveCGM Browser ActiveX control contains multiple buffer overflows, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

The Corel ActiveCGM Browser is an ActiveX control that allows viewing of Computer Graphic Metafiles (CGMs) in a web browser. The ActiveCGM Browser ActiveX control, which is provided by acgm.dll, contains multiple buffer overflows. Note that the control was created by Micrografx, which was acquired by Corel.

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. The attacker could also cause Internet Explorer (or the program using the WebBrowser control) to crash.

III. Solution

Apply an update

This vulnerability is addressed in version 7.1.4.19 of the ActiveCGM Browser ActiveX control. Please check with your vendor for update availability. Also consider the following workarounds

Disable the ActiveCGM ActiveX control in Internet Explorer

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

{F5D98C43-DB16-11cf-8ECA-0000C0FD59C7}

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{F5D98C43-DB16-11cf-8ECA-0000C0FD59C7}]
"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
Corel Corporation	Vulnerable	11-Jun-2007

References

http://www.cert.org/tech_tips/securing_browser/#Internet_Explorer
http://www.corel.com/servlet/Satellite?pagename=Corel3/Products/Display&pid=1047022927836
http://support.microsoft.com/kb/240797

Credit

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

This document was written by Will Dormann.

Other Information

Date Public	06/13/2007
Date First Published	06/13/2007 01:50:31 PM
Date Last Updated	06/13/2007
CERT Advisory
CVE Name	CVE-2007-2921
Metric	1.95
Document Revision	7