Public Vulnerability Reports

Microsoft Windows Kernel Invalid Trap-Frame Management Privilege Escalation Vulnerability

12.13.11

BACKGROUND

Microsoft Windows is an operating system produced by Microsoft. More information can be found at the following vendor's website:

http://windows.microsoft.com

DESCRIPTION

Local exploitation of a design error vulnerability in Microsoft Corp.'s Windows operating system could allow an attacker to gain elevated privileges on the system.

Windows trap-frames are internal structures in the Windows kernel. They are used to store various characteristics of the processor state, such as general purpose, debug and segment registers' values, CPU flags (EFlags) and exception handling-related information.

A trap frame structure is formed on the stack every time an exception or interrupt (be it user or hardware interrupt) is generated or delivered to the CPU. When one of the above conditions takes place, the processor pushes the most crucial components of the execution context on the stack.

When an interrupt trigges a transition from userland to kernel, a design flaw will make Windows kernel mistakenly assume that the trap frame is generated from a kernel-to-kernel transition, and thus restore an invalid stack pointer. This allows an arbitrary write to any kernel memory or forcing a return to an arbitrary code segment. This can result in the execution of arbitrary code.

ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary code with kernel privileges. To exploit this vulnerability, an attacker needs valid logon credentials, and the ability to execute a specially crafted program on the targeted system.

DETECTION

The following Microsoft products are vulnerable:

  • Windows XP SP 3
  • Windows Server 2003 SP 2
  • Windows Vista SP 2
  • Windows Server 2008 for 32-bit Systems SP 2
  • Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems SP 1

WORKAROUND

iDefense is currently unaware of any workaround for this issue.

VENDOR RESPONSE

Microsoft has released updates to address this vulnerability. For more information, consult their advisory at the following URL.

http://technet.microsoft.com/en-us/security/bulletin/ms11-098

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-2018 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

09/08/2011 Initial Vendor Notification
09/08/2011 Initial Vendor Reply
12/13/2011 Coordinated Public Disclosure

CREDIT

This vulnerability was reported to iDefense by Matt "j00ru" Jurczyk.

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LEGAL NOTICES

Copyright © 2011 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.