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Microsoft DebugView Privilege Escalation Vulnerability

11.06.07

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

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.

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.

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.

WORKAROUND

iDefense is currently unaware of any effective workaround for this issue.

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

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.

DISCLOSURE TIMELINE

08/21/2007 Initial vendor notification
08/21/2007 Initial vendor response
11/06/2007 Public disclosure

CREDIT

This vulnerability was reported to VeriSign iDefense by Stephen Fewer of Harmony Security (www.harmonysecurity.com)

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LEGAL NOTICES

Copyright © 2007 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.