I. BACKGROUND
Yahoo! Messenger is a instant messaging application that allows users to
chat online, share files, conduct PC to PC calls and more. More
information can be found on the vendor's site at the following URL.
http://messenger.yahoo.com/
II. DESCRIPTION
Remote exploitation of multiple buffer overflow vulnerabilities in Yahoo
Inc.'s Yahoo! Messenger 8.1 allows attackers to execute arbitrary code
with the privileges of the currently logged in user.
When Yahoo Messenger 8.1 is installed, the following vulnerable ActiveX
Control is registered on the system.
ProgID: YVerInfo.GetInfo.1
Clsid: D5184A39-CBDF-4A4F-AC1A-7A45A852C883
File: C:\Program Files\Yahoo!\Common\YVerInfo.dll
Version: 2006.8.24.1
Stack based buffer overflows can be triggered through either the fvCom()
or info() methods of this class.
III. ANALYSIS
Exploitation allows attackers to execute arbitrary code with the
privileges of the currently logged in user. Users would be required to
have a vulnerable version of the target software installed and be lured
to a malicious site.
It is important to note that functions within this class can only be
called if the control believes it is being run from the yahoo.com
domain. In order for this exploit to be triggered an attacker would
either have to leverage a Cross-Site Scripting vulnerability in the
yahoo.com domain, or be able to control the targeted user's DNS
resolution for the domain.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in version
8.1 of Yahoo Instant Messenger. Previous versions are suspected to be
vulnerable as well.
V. WORKAROUND
Setting the kill bit for the vulnerable ActiveX control's CLSID will
prevent these issues from be exploited within Internet Explorer.
VI. VENDOR RESPONSE
Yahoo Inc. has addressed these vulnerabilities by releasing an updated
version of Yahoo! Messenger. More information is available at the
following URL.
http://messenger.yahoo.com/security_update.php?id=082907
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-4515 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which
standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
08/21/2007 Initial vendor notification
08/21/2007 Initial vendor response
08/30/2007 Coordinated public disclosure
IX. CREDIT
The discoverer of this vulnerability wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please e-mail customer service for permission.
Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.
