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Multiple Vendor OpenOffice EMF EMR_BITBLT Record Integer Overflow Vulnerability

04.17.08

BACKGROUND

OpenOffice is an open-source desktop office suite for many of today's popular operating systems. One of the file formats that OpenOffice supports is Windows Enhanced Metafile (EMF). EMF files are used to render images. More information is available from the following URL.

http://www.openoffice.org/

DESCRIPTION

Remote exploitation of an integer overflow vulnerability in OpenOffice, as included in various vendors' operating system distributions, allows attackers to execute arbitrary code with the privileges of the logged in user.

The vulnerability exists within the code responsible for parsing the EMR_STRETCHBLT record in an EMF file. This code reads in two 32-bit integers from the file, and then uses them in an arithmetic operation that calculates the number of bytes to allocate for a dynamic buffer. This calculation can overflow, resulting in an insufficiently sized buffer being allocated. Subsequently, this buffer is overflowed with data from the file.

ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the user opening the file. In order to exploit this vulnerability, an attacker must persuade a user to open a malicious file.

DETECTION

iDefense confirmed the existence of this vulnerability in OpenOffice version 2.3. Other versions may also be affected.

WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VENDOR RESPONSE

The OpenOffice.org team has addressed these vulnerabilities with the release of version 2.4. For more information, consult the OOo Security Bulletin at the following URL.

http://www.openoffice.org/security/cves/CVE-2007-5746.html

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-5746 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

10/29/2007 Initial vendor notification
10/30/2007 Initial vendor response
04/17/2008 Coordinated public disclosure

CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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LEGAL NOTICES

Copyright © 2008 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.