iDefense Security Advisory 11.06.07 http://labs.idefense.com/intelligence/vulnerabilities/ Nov 06, 2007 I. BACKGROUND DebugView is a system analysis tool designed to display debug messages being generated on the system. More information is available on the vendor's site at the following URL. http://www.microsoft.com/technet/sysinternals/utilities/debugview.mspx II. DESCRIPTION Local exploitation of a design error vulnerability in Microsoft's DebugView could allow attackers to execute arbitrary kernel code. As part of its design, DebugView loads a kernel module Dbgv.sys. This module includes functionality that can be abused to copy user supplied data into the kernel, to controlled addresses. This allows malicious users to inject arbitrary code into the running kernel. III. ANALYSIS Exploitation allows attackers to modify the kernel, resulting in the arbitrary execution of code in kernel context. In order to exploit this vulnerability, an administrator must launch the DebugView application, which will load the Dbgv.sys driver into the kernel. Once loaded, the vulnerable kernel module will be accessible by all users, and will remain loaded until the system is rebooted. IV. DETECTION iDefense confirmed the existence of this vulnerability in Microsoft DebugView version 4.64. The specific file version of Dbgv.sys is 4.60.0.0. This file is deleted automatically after being loaded and will not be found on disk. Previous versions are suspected to be vulnerable as well. V. WORKAROUND iDefense is currently unaware of any effective workaround for this issue. VI. VENDOR RESPONSE Microsoft Sysinternals has addressed this vulnerability by releasing version 4.72 of DebugView. For more information, visit the following URL. http://www.microsoft.com/technet/sysinternals/utilities/debugview.mspx VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-4223 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 08/21/2007 Initial vendor notification 08/21/2007 Initial vendor response 11/06/2007 Public disclosure IX. CREDIT This vulnerability was reported to VeriSign iDefense by Stephen Fewer of Harmony Security (www.harmonysecurity.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 © 2007 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@xxxxxxxxxxxx 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.