Vulnerability Note VU#174177

Zoomify Viewer ActiveX control multiple stack buffer overflows

Overview

The Zoomify Viewer ActiveX control contains multiple stack buffer overflows, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

Zoomify provides software to incorporate zoomable images into web sites. One of the Zoomify products is an ActiveX control for use with Internet Explorer web browsers. The Zoomify Viewer ActiveX control, which is provided by ZActiveX.dll, contains multiple stack buffer overflows.

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

We are currently unaware of a practical solution to this problem. Please consider the following workarounds

Disable the Zoomify 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:

{F7DC2A2E-FC34-11D3-B1D9-00A0C99B41BB}

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{F7DC2A2E-FC34-11D3-B1D9-00A0C99B41BB}]
"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
Zoomify, Inc.	Vulnerable	11-Jun-2007

References

http://www.cert.org/tech_tips/securing_browser/#Internet_Explorer
http://support.microsoft.com/kb/240797
http://secunia.com/advisories/25625/

Credit

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

This document was written by Will Dormann.

Other Information

Date Public	06/11/2007
Date First Published	06/11/2007 03:56:14 PM
Date Last Updated	06/14/2007
CERT Advisory
CVE Name	CVE-2007-2920
Metric	1.55
Document Revision	7