[NT] Microsoft Excel Malformed Object Memoy Corruption Vulnerability (MS08-074)

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Microsoft Excel Malformed Object Memoy Corruption Vulnerability (MS08-074)


Excel is the spreadsheet application included with Microsoft Corp.'s
Office productivity software suite. Remote exploitation of a memory
corruption vulnerability in Microsoft Corp.'s Excel spreadsheet could
allow attackers to execute arbitrary code with the privileges of the
current user.


Vulnerable Systems:
* Office 2000 SP3 fully patched as of July 2008.

This issue exists in the handling of certain malformed object records
within an Excel spreadsheet (XLS), allowing memory corruption to occur.
This could lead to an exploitable situation.

iDefense's proof of concept code can redirect the program execution flow
to a user controllable address on Excel 2000 SP3, and crash on other
versions of Excel, including Excel XP SP3, Excel 2003 SP3 and Excel 2007

Exploitation allows an attacker to execute arbitrary code in the context
of the currently logged-on user. To exploit this vulnerability, the
attacker must persuade a user to open a specially crafted Excel (XLS)

Likely attack vectors include sending the file as an e-mail attachment or
linking to the file on a website. By default, systems with Office 2000
installed will open Office documents, including Excel spreadsheet files,
from websites without prompting the user. This allows attackers to exploit
this vulnerability without user interaction. Later versions of Office do
not open these documents automatically unless the user has chosen this

Using the Office Document Open Confirmation Tool for Office 2000 can
prevent Office files from opening automatically from web sites. Use of
this tool is highly recommended for users still using Office 2000.

Vendor response:
Microsoft Corp. has released a patch which addresses this issue. For more
information, consult their advisory at the following URL.

CVE Information:

Disclosure timeline:
07/21/2008 - Initial Vendor Notification
07/22/2008 - Initial Vendor Reply
07/24/2008 - Additional Vendor Feedback
12/09/2008 - Coordinated Public Disclosure


The information has been provided by
<mailto:idlabs-advisories@xxxxxxxxxxxx> iDefense Labs Security Advisories.
The original article can be found at:


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