Yahoo Messenger YVerInfo.dll ActiveX Multiple Remote Buffer
Overflow
Vulnerabilities
iDefense Security Advisory 08.30.07
http://labs.idefense.com/intelligence/vulnerabilities/
Aug 30, 2007
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.co
m/
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 FilesYahoo!CommonYVerInfo.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.
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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.
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