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iDefense Security Advisory 12.09.08
Dec 09, 2008
Internet Explorer is a graphical web browser developed by Microsoft
Corp. that has been included with Microsoft Windows since 1995. For
more information about Internet Explorer, please the visit following
Remote exploitation of a stack buffer overflow vulnerability while
handling specific HTML tags in Microsoft Corp.'s Internet Explorer web
browser allows attackers to execute arbitrary code within the context
of the affected user.
On Internet Explorer 5.01 a function return address can be overwritten
with attacker controlled data which results in an exploitable
condition. However on Internet Explorer 6 the vulnerability will only
overflow one byte. For Internet Explorer 6 on Windows 2000 platform,
the overflowed byte is in a local variable, and overwriting it doesn't
affect program execution at all. For Internet Explorer 6 on Windows XP
SP2, the overflowed byte is in the stack cookie, which causes Internet
Explorer to terminate and only results in a denial of service.
Successful exploitation of this vulnerability would allow an attacker to
execute arbitrary code in the context of the user running the Internet
Explorer. However, the execution of arbitrary code is only possible on
Windows 2000 SP4 running Internet Explorer 5.01.
Exploitation would require an attacker to persuade a user to visit a
malicious website using Internet Explorer.
As of September 2008, iDefense confirms that Internet Explorer 5.01 on
Windows 2000 SP4, is vulnerable. It also causes denial of service for
Internet Explorer 6 on Windows XP SP2. Internet Explorer 7 is not
iDefense is not aware of any effective workaround for this issue.
Customers are encouraged to upgrade Internet Explorer to version 6 or
VI. VENDOR RESPONSE
Microsoft has released a patch which addresses this issue. For more
information, consult their advisory at the following URL.
Microsoft recommends that customers apply the update immediately.
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-4261 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
VIII. DISCLOSURE TIMELINE
08/26/2008 Initial Vendor Notification
08/26/2008 Initial Vendor Reply
09/24/2008 Additional Vendor Feedback
12/02/2008 Additional Vendor Feedback
12/09/2008 Coordinated Public Disclosure
This vulnerability was discovered by Jun Mao of iDefense Labs.
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X. LEGAL NOTICES
Copyright =A9 2008 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 email@example.com 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.
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