iDefense Security Advisory 07.15.09: Microsoft Office Publisher 2007 Arbitrary Pointer Dereference Vulnerability

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iDefense Security Advisory 07.14.09
http://labs.idefense.com/intelligence/vulnerabilities/
Jul 14, 2009

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 )

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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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