iDefense Security Advisory 02.12.08 http://labs.idefense.com/intelligence/vulnerabilities/ Feb 12, 2008 I. BACKGROUND Microsoft Works is a word processor created by Microsoft in the 1980s. Microsoft Office, a widely use productivity suite, is distributed with converters for various versions of the Works file format. II. DESCRIPTION Remote exploitation of a heap corruption vulnerability in Microsoft Corp.'s Works Converter, as included with Microsoft Office, could potentially allow an attacker to execute arbitrary code as the current user. This vulnerability stems from improper input validation of OLE structures within wkcvqd01.dll when converting a Microsoft Works document (WPS extension) to Rich Text Format (RTF). When certain fields are modified, such as the length or count values, heap corruption can occur. This leads to a potentially exploitable condition. III. ANALYSIS Exploitation allows attackers to execute arbitrary code as the user that converts a specially crafted Works document. Exploitation might require the installation of additional Microsoft Office components. When installing Microsoft Office, there are several installation options for converters. In corporate environments, the required components are usually set to be installed from the hard drive on first use. However, one of the installation options causes a request for the installation media. If this option is used, the media prompt may help mitigate exploitation. Microsoft first released a fix for this vulnerability as part of Office 2003 SP3. No specific mention was made about this vulnerability at that time. IV. DETECTION iDefense has confirmed that wkcvqd01.dll version 7.03.0616.0, as included with Microsoft Office 2003, is vulnerable to this issue. Older versions are assumed to be vulnerable as well. Additionally, Microsoft Works itself is suspected to be vulnerable. V. WORKAROUND User awareness is the best defense against this type of attack. Users should be reminded not to open attachments or click URLs from untrusted sources. VI. VENDOR RESPONSE Microsoft has officially addressed this vulnerability with Security Bulletin MS08-011. For more information, consult their bulletin at the following URL. http://www.microsoft.com/technet/security/Bulletin/ms08-011.mspx VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-0216 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 11/13/2006 Initial vendor notification 11/14/2006 Initial vendor response 09/17/2007 Office 2003 SP3 released (fix included) 02/12/2008 Coordinated public disclosure IX. CREDIT This vulnerability was reported to VeriSign iDefense by Damian Put (pucik@overflow.pl). 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 © 2008 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 customerservice@idefense.com 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. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/