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.
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.
File: C:\Program Files\Yahoo!\Common\YVerInfo.dll
Stack based buffer overflows can be triggered through either the fvCom() or info() methods of this class.
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.
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.
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.
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
The discoverer of this vulnerability wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
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