iDefense Security Advisory 05.12.09: Microsoft PowerPoint 4.2 Conversion Filter Heap Corruption Vulnerability

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

I. BACKGROUND

Microsoft PowerPoint is an application used for constructing
presentations, and comes with the Microsoft Office Suite. For more
information, see the vendor's site found at the following link.

http://office.microsoft.com/en-us/powerpoint/default.aspx

II. DESCRIPTION

Remote exploitation of a heap corruption vulnerability in Microsoft
Corp.'s PowerPoint could allow an attacker to execute arbitrary code
with the privileges of the current user.

In particular, there is code that parses structures in the PowerPoint
file. If the number of these structures is greater than a certain
value, then memory corruption will occur. This memory corruption leads
to the executing of arbitrary code.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary
code with the privileges of the user opening the file. To exploit this
vulnerability, an attacker needs to convince a user to open a malicious
file.

IV. DETECTION

iDefense has confirmed the existence of these vulnerabilities in the
following versions of PowerPoint:

• PowerPoint 2000 SP3

• PowerPoint XP SP3

PowerPoint 2003 SP2 and SP3 contain the vulnerable code, but by default
are unable to open PowerPoint 4.2 formatted files. This is due to the
Office 2003 SP2/SP3 File Block Policy, which limits the file formats
that Office applications will open without special permissions. If the
targeted user has disabled the File Block Policy settings in PowerPoint
2003 SP3, then they are vulnerable. However, this is a non-default
configuration. More on this policy can be found at the following URL.

http://support.microsoft.com/kb/938810

Office 2007 and Office 2007 SP1 are not vulnerable to these issues.

V. WORKAROUND

Use the cacls program to deny access to the DLL containing the
vulnerable code, PP4X32.DLL. This will prevent the vulnerable DLL from
loading in PowerPoint, which will also prevent users from importing
PowerPoint 4.0 files. If Office 2003 SP3 is being used, then the
default behavior is to block the opening of PowerPoint 4.0 files. If
the default behavior has been changed, restoring it is an effective
workaround.

VI. VENDOR RESPONSE

iDefense is currently working with the vendor to address this issue.
Since there is no vendor fix at this time, please handle this
information with sensitivity.

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2009-0223 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

02/24/2009 - Initial Contact
02/24/2009 - Initial Response
02/24/2009 - PoC Requested
03/05/2009 - PoC Sent
03/06/2009 - Vendor requests clarification - cannot reproduce
04/03/2009 - Vendor Case # 9037 set
04/23/2009 - Requested CVE from Vendor
04/23/2009 - Vendor set disclosure date of June 9
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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