Vulnerability Note VU#507433

Microsoft Speech API ActiveX controls contain buffer overflows

Overview

The Microsoft Speech API ActiveListen and ActiveVoice ActiveX controls contain multiple buffer overflows, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

Microsoft Speech API is a software package that provides text-to-speech and speech recognition capabilities. The Microsoft Speech API includes ActiveX controls called ActiveListen and ActiveVoice, which are provided by Xlisten.dll and XVoice.dll, respectively. These ActiveX controls contain multiple buffer overflow vulnerabilities.

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 issue is addressed by Microsoft Security Bulletin MS07-033. This update sets the kill bit for the vulnerable controls. Please also consider the following workarounds

Disable the Speech API ActiveX controls in Internet Explorer

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

{4E3D9D1F-0C63-11D1-8BFB-0060081841DE}
{EEE78591-FE22-11D0-8BEF-0060081841DE}

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 these controls:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINESOFTWAREMicrosoftInternet ExplorerActiveX Compatibility{4E3D9D1F-0C63-11D1-8BFB-0060081841DE}]
"Compatibility Flags"=dword:00000400

[HKEY_LOCAL_MACHINESOFTWAREMicrosoftInternet ExplorerActiveX Compatibility{EEE78591-FE22-11D0-8BEF-0060081841DE}]
"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
Animated Programs	Vulnerable	12-Jun-2007
Earthlink	Vulnerable	12-Jun-2007
Microsoft Corporation	Vulnerable	12-Jun-2007
Nuance Communications, Inc.	Vulnerable	12-Jun-2007

References

http://www.cert.org/tech_tips/securing_browser/#Internet_Explorer
http://www.microsoft.com/technet/security/Bulletin/MS07-033.mspx
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	06/12/2007
Date First Published	06/12/2007 01:46:31 PM
Date Last Updated	06/12/2007
CERT Advisory
CVE Name	CVE-2007-2222
Metric	8.26
Document Revision	10