Microsoft Security Bulletin MS11-098 - Important

Vulnerability in Windows Kernel Could Allow Elevation of Privilege (2633171)

Published: Tuesday, December 13, 2011 | Updated: Wednesday, February 01, 2012

Version: 1.1

General Information

Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Windows. The vulnerability could allow elevation of privilege if an attacker logs on to an affected system and runs a specially crafted application designed to exploit the vulnerability. An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability. The vulnerability could not be exploited remotely or by anonymous users.

This security update is rated Important for all supported 32-bit editions of Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by helping to ensure that the Windows kernel initializes objects in memory. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update at the earliest opportunity using update management software, or by checking for updates using the Microsoft Update service.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Known Issues. Microsoft Knowledge Base Article 2633171 documents the currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues.

Affected and Non-Affected Software

The following software have been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

Affected Software

Operating System	Maximum Security Impact	Aggregate Severity Rating	Bulletins Replaced by this Update
Windows XP Service Pack 3	Elevation of Privilege	Important	MS10-047
Windows Server 2003 Service Pack 2	Elevation of Privilege	Important	MS10-021
Windows Vista Service Pack 2	Elevation of Privilege	Important	MS11-068
Windows Server 2008 for 32-bit Systems Service Pack 2*	Elevation of Privilege	Important	MS11-068
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1	Elevation of Privilege	Important	MS11-068

*Server Core installation affected. This update applies, with the same severity rating, to supported editions of Windows Server 2008 or Windows Server 2008 R2 as indicated, whether or not installed using the Server Core installation option. For more information on this installation option, see the TechNet articles, Managing a Server Core Installation and Servicing a Server Core Installation. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008 and Windows Server 2008 R2; see Compare Server Core Installation Options.

Non-Affected Software

Operating System
Windows XP Professional x64 Edition Service Pack 2
Windows Server 2003 x64 Edition Service Pack 2
Windows Server 2003 with SP2 for Itanium-based Systems
Windows Vista x64 Edition Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for Itanium-based Systems Service Pack 2
Windows 7 for x64-based Systems and Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems and Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for Itanium-based Systems and Windows Server 2008 R2 for Itanium-based Systems Service Pack 1

Frequently Asked Questions (FAQ) Related to This Security Update

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software	Windows Kernel Exception Handler Vulnerability - CVE-2011-2018	Aggregate Severity Rating
Windows XP Service Pack 3	Important Elevation of Privilege	Important
Windows Server 2003 Service Pack 2	Important Elevation of Privilege	Important
Windows Vista Service Pack 2	Important Elevation of Privilege	Important
Windows Server 2008 for 32-bit Systems Service Pack 2*	Important Elevation of Privilege	Important
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1	Important Elevation of Privilege	Important

Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

An elevation of privilege vulnerability exists in the Windows kernel due to the way the kernel accesses an object that has not been correctly initialized. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2011-2018.

Mitigating Factors for Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

Workarounds for Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

FAQ for Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

What is the scope of the vulnerability?
This is an elevation of privilege vulnerability. An attacker who successfully exploited this vulnerability could execute arbitrary code and take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

What causes the vulnerability?
The vulnerability is caused when the Windows kernel accesses an object that has not been correctly initialized.

What is the Windows kernel?
The Windows Kernel is the core of the operating system. It provides system level services such as device management and memory management, allocates processor time to processes, and manages error handling.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take complete control over an affected system.

What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do?
The update addresses the vulnerability by helping to ensure that the Windows kernel initializes objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers when this security bulletin was originally issued.

Update Information

Detection and Deployment Tools and Guidance

Security Central

Manage the software and security updates you need to deploy to the servers, desktop, and mobile systems in your organization. For more information see the TechNet Update Management Center. The Microsoft TechNet Security Web site provides additional information about security in Microsoft products.

Security updates are available from Microsoft Update and Windows Update. Security updates are also available from the Microsoft Download Center. You can find them most easily by doing a keyword search for "security update."

Finally, security updates can be downloaded from the Microsoft Update Catalog. The Microsoft Update Catalog provides a searchable catalog of content made available through Windows Update and Microsoft Update, including security updates, drivers and service packs. By searching using the security bulletin number (such as, "MS07-036"), you can add all of the applicable updates to your basket (including different languages for an update), and download to the folder of your choosing. For more information about the Microsoft Update Catalog, see the Microsoft Update Catalog FAQ.

Detection and Deployment Guidance

Microsoft provides detection and deployment guidance for security updates. This guidance contains recommendations and information that can help IT professionals understand how to use various tools for detection and deployment of security updates. For more information, see Microsoft Knowledge Base Article 961747.

Microsoft Baseline Security Analyzer

Microsoft Baseline Security Analyzer (MBSA) allows administrators to scan local and remote systems for missing security updates as well as common security misconfigurations. For more information about MBSA, visit Microsoft Baseline Security Analyzer.

The following table provides the MBSA detection summary for this security update.

Software	MBSA
Windows XP Service Pack 3	Yes
Windows Server 2003 Service Pack 2	Yes
Windows Vista Service Pack 2	Yes
Windows Server 2008 for 32-bit Systems Service Pack 2	Yes
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1	Yes

Note For customers using legacy software not supported by the latest release of MBSA, Microsoft Update, and Windows Server Update Services, please visit Microsoft Baseline Security Analyzer and reference the Legacy Product Support section on how to create comprehensive security update detection with legacy tools.

Windows Server Update Services

Windows Server Update Services (WSUS) enables information technology administrators to deploy the latest Microsoft product updates to computers that are running the Windows operating system. For more information about how to deploy security updates using Windows Server Update Services, see the TechNet article, Windows Server Update Services.

Systems Management Server

The following table provides the SMS detection and deployment summary for this security update.

Software	SMS 2003 with ITMU	Configuration Manager 2007
Windows XP Service Pack 3	Yes	Yes
Windows Server 2003 Service Pack 2	Yes	Yes
Windows Vista Service Pack 2	Yes	Yes
Windows Server 2008 for 32-bit Systems Service Pack 2	Yes	Yes
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1	Yes	Yes

Note Microsoft discontinued support for SMS 2.0 on April 12, 2011. For SMS 2003, Microsoft also discontinued support for the Security Update Inventory Tool (SUIT) on April 12, 2011. Customers are encouraged to upgrade to System Center Configuration Manager 2007. For customers remaining on SMS 2003 Service Pack 3, the Inventory Tool for Microsoft Updates (ITMU) is also an option.

For SMS 2003, the SMS 2003 Inventory Tool for Microsoft Updates (ITMU) can be used by SMS to detect security updates that are offered by Microsoft Update and that are supported by Windows Server Update Services. For more information about the SMS 2003 ITMU, see SMS 2003 Inventory Tool for Microsoft Updates. For more information about SMS scanning tools, see SMS 2003 Software Update Scanning Tools. See also Downloads for Systems Management Server 2003.

System Center Configuration Manager 2007 uses WSUS 3.0 for detection of updates. For more information about Configuration Manager 2007 Software Update Management, visit System Center Configuration Manager 2007.

For more information about SMS, visit the SMS Web site.

For more detailed information, see Microsoft Knowledge Base Article 910723: Summary list of monthly detection and deployment guidance articles.

Update Compatibility Evaluator and Application Compatibility Toolkit

Updates often write to the same files and registry settings required for your applications to run. This can trigger incompatibilities and increase the time it takes to deploy security updates. You can streamline testing and validating Windows updates against installed applications with the Update Compatibility Evaluator components included with Application Compatibility Toolkit.

The Application Compatibility Toolkit (ACT) contains the necessary tools and documentation to evaluate and mitigate application compatibility issues before deploying Microsoft Windows Vista, a Windows Update, a Microsoft Security Update, or a new version of Windows Internet Explorer in your environment.

Security Update Deployment

Inclusion in Future Service Packs	The update for this issue will be included in a future service pack or update rollup
Deployment
Installing without user intervention	For Windows XP Service Pack 3: WindowsXP-KB2633171-x86-enu.exe /quiet
Installing without restarting	For Windows XP Service Pack 3: WindowsXP-KB2633171-x86-enu.exe /norestart
Update log file	KB2633171.log
Further information	See the subsection, Detection and Deployment Tools and Guidance
Restart Requirement
Restart required?	Yes, you must restart your system after you apply this security update.
HotPatching	Not applicable
Removal Information	Use Add or Remove Programs tool in Control Panel or the Spuninst.exe utility located in the %Windir%\$NTUninstallKB2633171$\Spuninst folder
File Information	See Microsoft Knowledge Base Article 2633171
Registry Key Verification	For all supported 32-bit editions of Windows XP: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP4\KB2633171\Filelist

Supported Security Update Installation Switches
Switch	Description
/help	Displays the command-line options.
Setup Modes
/passive	Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.
/quiet	Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.
Restart Options
/norestart	Does not restart when installation has completed.
/forcerestart	Restarts the computer after installation and force other applications to close at shutdown without saving open files first.
/warnrestart[:x]	Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.
/promptrestart	Displays a dialog box prompting the local user to allow a restart.
Special Options
/overwriteoem	Overwrites OEM files without prompting.
/nobackup	Does not back up files needed for uninstall.
/forceappsclose	Forces other programs to close when the computer shuts down.
/log:path	Allows the redirection of installation log files.
/integrate:path	Integrates the update into the Windows source files. These files are located at the path that is specified in the switch.
/extract[:path]	Extracts files without starting the Setup program.
/ER	Enables extended error reporting.
/verbose	Enables verbose logging. During installation, creates %Windir%\CabBuild.log. This log details the files that are copied. Using this switch may cause the installation to proceed more slowly.

Supported Spuninst.exe Switches
Switch	Description
/help	Displays the command-line options.
Setup Modes
/passive	Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.
/quiet	Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.
Restart Options
/norestart	Does not restart when installation has completed
/forcerestart	Restarts the computer after installation and force other applications to close at shutdown without saving open files first.
/warnrestart[:x]	Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.
/promptrestart	Displays a dialog box prompting the local user to allow a restart.
Special Options
/forceappsclose	Forces other programs to close when the computer shuts down.
/log:path	Allows the redirection of installation log files.

Inclusion in Future Service Packs	The update for this issue will be included in a future service pack or update rollup
Deployment
Installing without user intervention	For all supported 32-bit editions of Windows Server 2003: WindowsServer2003-KB2633171-x86-enu.exe /quiet
Installing without restarting	For all supported 32-bit editions of Windows Server 2003: WindowsServer2003-KB2633171-x86-enu.exe /norestart
Update log file	KB2633171.log
Further information	See the subsection, Detection and Deployment Tools and Guidance
Restart Requirement
Restart required?	Yes, you must restart your system after you apply this security update.
HotPatching	This security update does not support HotPatching. For more information about HotPatching, see Microsoft Knowledge Base Article 897341.
Removal Information	Use Add or Remove Programs tool in Control Panel or the Spuninst.exe utility located in the %Windir%\$NTUninstallKB2633171$\Spuninst folder
File Information	See Microsoft Knowledge Base Article 2633171
Registry Key Verification	HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows Server 2003\SP3\KB2633171\Filelist

Supported Security Update Installation Switches
Switch	Description
/help	Displays the command-line options.
Setup Modes
/passive	Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.
/quiet	Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.
Restart Options
/norestart	Does not restart when installation has completed.
/forcerestart	Restarts the computer after installation and force other applications to close at shutdown without saving open files first.
/warnrestart[:x]	Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.
/promptrestart	Displays a dialog box prompting the local user to allow a restart.
Special Options
/overwriteoem	Overwrites OEM files without prompting.
/nobackup	Does not back up files needed for uninstall.
/forceappsclose	Forces other programs to close when the computer shuts down.
/log:path	Allows the redirection of installation log files.
/integrate:path	Integrates the update into the Windows source files. These files are located at the path that is specified in the switch.
/extract[:path]	Extracts files without starting the Setup program.
/ER	Enables extended error reporting.
/verbose	Enables verbose logging. During installation, creates %Windir%\CabBuild.log. This log details the files that are copied. Using this switch may cause the installation to proceed more slowly.

Supported Spuninst.exe Switches
Switch	Description
/help	Displays the command-line options.
Setup Modes
/passive	Unattended Setup mode. No user interaction is required, but installation status is displayed. If a restart is required at the end of Setup, a dialog box will be presented to the user with a timer warning that the computer will restart in 30 seconds.
/quiet	Quiet mode. This is the same as unattended mode, but no status or error messages are displayed.
Restart Options
/norestart	Does not restart when installation has completed.
/forcerestart	Restarts the computer after installation and force other applications to close at shutdown without saving open files first.
/warnrestart[:x]	Presents a dialog box with a timer warning the user that the computer will restart in x seconds. (The default setting is 30 seconds.) Intended for use with the /quiet switch or the /passive switch.
/promptrestart	Displays a dialog box prompting the local user to allow a restart.
Special Options
/forceappsclose	Forces other programs to close when the computer shuts down.
/log:path	Allows the redirection of installation log files.

Inclusion in Future Service Packs	The update for this issue will be included in a future service pack or update rollup
Deployment
Installing without user intervention	For all supported 32-bit editions of Windows Vista: Windows6.0-KB2633171-x86.msu /quiet
Installing without restarting	For all supported 32-bit editions of Windows Vista: Windows6.0-KB2633171-x86.msu /quiet /norestart
Further information	See the subsection, Detection and Deployment Tools and Guidance
Restart Requirement
Restart required?	Yes, you must restart your system after you apply this security update.
HotPatching	Not applicable.
Removal Information	WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates and select from the list of updates.
File Information	See Microsoft Knowledge Base Article 2633171
Registry Key Verification	Note A registry key does not exist to validate the presence of this update.

Supported Security Update Installation Switches
Switch	Description
/?, /h, /help	Displays help on supported switches.
/quiet	Suppresses the display of status or error messages.
/norestart	When combined with /quiet, the system will not be restarted after installation even if a restart is required to complete installation.

Inclusion in Future Service Packs	The update for this issue will be included in a future service pack or update rollup
Deployment
Installing without user intervention	For all supported 32-bit editions of Windows Server 2008: Windows6.0-KB2633171-x86.msu /quiet
Installing without restarting	For all supported 32-bit editions of Windows Server 2008: Windows6.0-KB2633171-x86.msu /quiet /norestart
Further information	See the subsection, Detection and Deployment Tools and Guidance
Restart Requirement
Restart required?	Yes, you must restart your system after you apply this security update.
HotPatching	Not applicable.
Removal Information	WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates and select from the list of updates.
File Information	See Microsoft Knowledge Base Article 2633171
Registry Key Verification	Note A registry key does not exist to validate the presence of this update.

Supported Security Update Installation Switches
Switch	Description
/?, /h, /help	Displays help on supported switches.
/quiet	Suppresses the display of status or error messages.
/norestart	When combined with /quiet, the system will not be restarted after installation even if a restart is required to complete installation.

Inclusion in Future Service Packs	The update for this issue will be included in a future service pack or update rollup
Deployment
Installing without user intervention	For all supported 32-bit editions of Windows 7: Windows6.1-KB2633171-x86.msu /quiet
Installing without restarting	For all supported 32-bit editions of Windows 7: Windows6.1-KB2633171-x86.msu /quiet /norestart
Further information	See the subsection, Detection and Deployment Tools and Guidance
Restart Requirement
Restart required?	Yes, you must restart your system after you apply this security update.
HotPatching	Not applicable.
Removal Information	To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, and then under Windows Update, click View installed updates and select from the list of updates.
File Information	See Microsoft Knowledge Base Article 2633171
Registry Key Verification	Note A registry key does not exist to validate the presence of this update.

Supported Security Update Installation Switches
Switch	Description
/?, /h, /help	Displays help on supported switches.
/quiet	Suppresses the display of status or error messages.
/norestart	When combined with /quiet, the system will not be restarted after installation even if a restart is required to complete installation.
/warnrestart:<seconds>	When combined with /quiet, the installer will warn the user before initiating restart.
/promptrestart	When combined with /quiet, the installer will prompt before initiating restart.
/forcerestart	When combined with /quiet, the installer will forcefully close applications and initiate restart.
/log:<file name>	Enables logging to specified file.
/extract:<destination>	Extracts the package contents to the destination folder.
/uninstall /kb:<KB Number>	Uninstalls the security update.

Other Information

Acknowledgments

Microsoft thanks the following for working with us to help protect customers:

Mateusz "j00ru" Jurczyk, working with VeriSign iDefense Labs, for reporting the Windows Kernel Exception Handler Vulnerability (CVE-2011-2018)

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please visit the active protections Web sites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Support

Customers in the U.S. and Canada can receive technical support from Security Support or 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates. For more information about available support options, see Microsoft Help and Support.
International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

V1.0 (December 13, 2011): Bulletin published.
V1.1 (February 1, 2012): Added a link to Microsoft Knowledge Base Article 2633171 under Known Issues in the Executive Summary.

Microsoft Security Bulletin MS11-098 - Important

Vulnerability in Windows Kernel Could Allow Elevation of Privilege (2633171)

General Information

Executive Summary

Affected and Non-Affected Software

Frequently Asked Questions (FAQ) Related to This Security Update

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

Mitigating Factors for Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

Workarounds for Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

FAQ for Windows Kernel Exception Handler Vulnerability - CVE-2011-2018

Update Information

Detection and Deployment Tools and Guidance

Security Update Deployment

Windows XP (all editions)

Deployment Information

Windows Server 2003 (all editions)

Deployment Information

Windows Vista (all editions)

Deployment Information

Windows Server 2008 (all editions)

Deployment Information

Windows 7 (all editions)

Deployment Information

Other Information

Acknowledgments

Microsoft Active Protections Program (MAPP)

Support

Disclaimer

Revisions