I. BACKGROUND

Microsoft Office Publisher is a desktop publishing application. For more information, please visit following website:

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

II. DESCRIPTION

Remote exploitation of an arbitrary pointer dereference vulnerability in version 2007 of Microsoft Corp.'s Publisher could allow an attacker to execute arbitrary code as the user running Publisher.

This vulnerability exists in PUBCONV.DLL module in Microsoft Publisher 2007. PUBCONV.DLL module is responsible for converting legacy format Publisher files (.pub) created by older version of Publisher into the Publisher 2007 format. A programming error causes that module to dereference the arbitrary attacker-controlled value as the address of a table of function pointers. This vulnerability allows attackers to execute arbitrary code on the victim's system.

III. ANALYSIS

Exploitation of this vulnerability would allow an attacker to execute arbitrary code on the affected system within the security context of the local user running Publisher. Thus, the level of compromise would depend upon the security context of that user. An attacker would need to craft a malicious file and either host it on a website or send it as an attachment in an e-mail. The attacker would then need to persuade the local user to open it. There is no way an attacker can force exploitation. Further, this vulnerability exists only in Microsoft Publisher 2007, further minimizing the risk of exploitation.

IV. DETECTION

iDefense comfired PUBCONV.DLL (version 12.0.6311.5000) in Microsoft Office Publisher 2007 is vulnerable. Microsoft Office Publisher 2000, 2002 and 2003 do not appear to be affected.

V. WORKAROUND

Deny access to the publish converter by changing the ACLs on the file. This can be accomplished as follows:

  cacls \Program Files\Microsoft Office\Office12\pubconv.dll /d everyone

Note: By doing so, Microsoft Office Publisher 2007 may not open previous versions of Publisher documents.

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/MS09-030.mspx

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2009-0566 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

01/08/2009 - Initial Contact
01/09/2009 - PoC Requested
01/09/2009 - PoC Sent
01/09/2009 - Vendor Case Number Assigned
02/20/2009 - Vendor Status Update
07/14/2009 - Coordinated Public Disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Lionel d'Hauenens (LaboSkopia) ( www.laboskopia.com )

Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php

Free tools, research and upcoming events
http://labs.idefense.com/

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 customer service 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.