Yahoo! Messenger AudioConf ActiveX Control buffer overflow vulnerability

Overview

The Yahoo! Messenger AudioConf ActiveX control contains a buffer overflow, which could allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

Description

Yahoo! Messenger is an instant messaging application. Yahoo! Messenger includes several ActiveX controls. The AudioConf ActiveX control, which is provided by yacscom.dll, contains a buffer overflow vulnerability.

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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.

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Solution

Apply an update

As specified in the Yahoo! Security Update, this issue is addressed in versions of Yahoo Messenger from March 13, 2007 or later. Version 1.0.0.48 or higher of yacscom.dll contains the fix.

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**Disable the YMailAttach ActiveX control in Internet Explorer **
The Yahoo! AudioConf ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSID:

{85A4A99C-8C3D-499E-A386-E0743DFF8FB7}

More information about how to set the kill bit is available in Microsoft Support Document 240797.

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.

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Vendor Information

388377

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Yahoo, Inc. __ Affected

Updated: April 09, 2007

Status

Affected

Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

See <http://messenger.yahoo.com/security_update.php;_ylt=AkQgcpun6x0v49V3Uxj7PSnlLdMF?id=031207&gt; for more details.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23388377 Feedback>).

CVSS Metrics

Group	Score	Vector
Base
Temporal
Environmental

References

• <http://messenger.yahoo.com/security_update.php?id=031207&gt;
• <http://www.zerodayinitiative.com/advisories/ZDI-07-012.html&gt;
• <http://secunia.com/advisories/24742/&gt;
• <http://www.frsirt.com/english/advisories/2007/1219&gt;
• <http://securitytracker.com/alerts/2007/Apr/1017867.html&gt;
• <http://support.microsoft.com/kb/240797&gt;
• <http://www.us-cert.gov/reading_room/securing_browser/#Internet_Explorer&gt;

Acknowledgements

Thanks to Yahoo and ZDI for information that was used in this report. Yahoo credits ZDI for reporting this vulnerability.

This document was written by Ryan Giobbi.

Other Information

CVE IDs:	CVE-2007-1680
Severity Metric:	10.21 Date Public: