Vulnerability Note VU#329673

BusinessObjects RptViewerAX ActiveX control stack buffer overflow

Overview

The BusinessObjects RptViewerAX ActiveX control contains a stack buffer overflow, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

BusinessObjects 6.5 includes an ActiveX control called RptViewerAX, which is provided by RptViewerAX.dll. This ActiveX control is marked as Safe for Scripting and Safe for Initialization, which means that they can be controlled by a web page in Internet Explorer. The RptViewerAX ActiveX control is vulnerable to stack buffer overflow.

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

According to the vendor:

This issue has been fixed in critical hot fix CHF74 for the affected software. Users are asked contact support if they are not on or above CFH74 for Business Objects 6.5. Users with valid subscriptions can login to the web site:

http://support.businessobjects.com/downloads/service_packs/default.asp
Select BusinessObjects 6.5.x a valid login is required.

Note that the vulnerable ActiveX control can be installed by using a BusinessObjects web server with Internet Explorer. Users that have obtained the RptViewerAX control in this way may wish to consider the following workarounds:

Disable the RptViewerAX ActiveX control in Internet Explorer

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

{B20D9D6A-0DEC-4d76-9BEF-175896006B4A}

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{B20D9D6A-0DEC-4d76-9BEF-175896006B4A}]
"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
Business Objects	Vulnerable	18-Mar-2008

References

http://www.cert.org/tech_tips/securing_browser/
http://support.businessobjects.com/downloads/service_packs/default.asp
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	03/18/2008
Date First Published	03/18/2008 10:49:38 AM
Date Last Updated	04/28/2008
CERT Advisory
CVE Name	CVE-2007-6254
US-CERT Technical Alerts
Metric	4.56
Document Revision	10