iDefense Security Advisory 05.12.09: Microsoft PowerPoint PPT95 Import Multiple Stack Buffer Overflow Vulnerabilities

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iDefense Security Advisory 05.12.09
http://labs.idefense.com/intelligence/vulnerabilities/
May 12, 2009

I. BACKGROUND

Microsoft PowerPoint is a presentation program that comes with Microsoft
Office. For more information consult the vendor's site at the following
URL.

http://office.microsoft.com/powerpoint

II. DESCRIPTION

Remote exploitation of multiple stack based buffer overflow
vulnerabilities in Microsoft Corp.'s PowerPoint could allow an attacker
to execute arbitrary code with the privileges of the current user.

The vulnerabilities exist within the importer for PowerPoint 95 format
files. This functionality is contained within the PP7X32.DLL.

The vulnerabilities occur when reading sound data from a PowerPoint
file. In both cases, a value representing a record length is read in
from the file. This value is then used to control the number of bytes
read into a fixed size stack buffer. There is no check performed to
ensure that the buffer can hold the number of bytes specified, which
results in a stack buffer overflow.

III. ANALYSIS

Exploitation of these vulnerabilities results in the execution of
arbitrary code with the privileges of the user opening the file. To
exploit these vulnerabilities, an attacker needs to convince a user to
open a malicious file. After opening the file, no further interaction
is needed to trigger the vulnerability.

Since the vulnerabilities are stack based buffer overflows, and it is
possible to overwrite SEH handlers stored on the stack, exploitation is
relatively simple.

IV. DETECTION

iDefense has confirmed the existence of these vulnerabilities in Office
XP SP3, and Office 2000 SP3.

V. WORKAROUND

Use the cacls program to deny access to the DLL containing the
vulnerable code, PP7X32.DLL. This will prevent the vulnerable DLL from
loading in PowerPoint, which will also prevent users from importing
PowerPoint 95 files.

VI. VENDOR RESPONSE

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

http://www.microsoft.com/technet/security/Bulletin/MS09-017.mspx

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2009-1129 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

04/25/2008 - Initial Contact
04/25/2008 - Initial Response
04/25/2008 - PoC Sent
07/22/2008 - Status Update Requested
07/23/2008 - Initial Response - Update planned in November
12/11/2008 - Status Update Received - no estimated release date
02/19/2009 - Status Update Received - new case manager, estimated
release date 06/09/2009
05/12/2009 - Coordinated Public Disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Marsu.

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X. LEGAL NOTICES

Copyright © 2009 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 protected] 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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