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Microsoft PowerPoint 4.2 Conversion Filter Stack Buffer Overflow Vulnerability

12.05.09

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

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.

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.

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.

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.

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

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2009-0227 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

12/03/2008 - Initial Contact
12/15/2008 - Clarification Requested
12/15/2008 - Clarification Sent
12/15/2008 - PoC Requested
12/15/2008 - PoC Sent
01/06/2009 - Vendor Case # 8820 set
01/20/2009 - Vendor set tentative disclosure date of 06/09/2009
05/12/2009 - Coordinated Public Disclosure

CREDIT

This vulnerability was reported to iDefense by Marsu.

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LEGAL NOTICES

Copyright © 2009 Verisign, 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.