Security Bulletin

Microsoft Security Bulletin MS13-019 - Important

Vulnerability in Windows Client/Server Run-time Subsystem (CSRSS) Could Allow Elevation of Privilege (2790113)

Published: February 12, 2013

Version: 1.0

General Information

Executive Summary

This security update resolves a publicly disclosed vulnerability in Microsoft Windows. The vulnerability could allow elevation of privilege if an attacker logs on to a system and runs a specially crafted application. An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability.

This security update is rated Important for all supported editions of Windows 7 and Windows 2008 R2. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by correcting the way that the Windows CSRSS handles 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. Most customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

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. None

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, see Microsoft Support Lifecycle.

Affected Software 

Operating System Maximum Security Impact Aggregate Severity Rating Updates Replaced
Windows 7
Windows 7 for 32-bit Systems (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows 7 for 32-bit Systems Service Pack 1 (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows 7 for x64-based Systems (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows 7 for x64-based Systems Service Pack 1 (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows Server 2008 R2
Windows Server 2008 R2 for x64-based Systems (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows Server 2008 R2 for Itanium-based Systems (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Server Core installation option
Windows Server 2008 R2 for x64-based Systems (Server Core installation) (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) (KB2790113) Elevation of Privilege Important KB2567680 in MS11-063

** **

Non-Affected Software

Operating System
Windows XP Service Pack 3
Windows XP Professional x64 Edition Service Pack 2
Windows Server 2003 Service Pack 2
Windows Server 2003 x64 Edition Service Pack 2
Windows Server 2003 with SP2 for Itanium-based Systems
Windows Vista Service Pack 2
Windows Vista x64 Edition Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for Itanium-based Systems Service Pack 2
Windows 8 for 32-bit Systems
Windows 8 for 64-bit Systems
Windows Server 2012
Windows RT

Where are the file information details?
Refer to the reference tables in the Security Update Deployment section for the location of the file information details.

Where are the hashes of the security updates?
The SHA1 and SHA2 hashes of the security updates can be used to verify the authenticity of downloaded security update packages. For the hash information pertaining to this update, see Microsoft Knowledge Base Article 2790113.

I am using an older release of the software discussed in this security bulletin. What should I do?
The affected software listed in this bulletin have been tested to determine which releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, see the Microsoft Support Lifecycle website.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. To determine the support lifecycle for your software release, see Select a Product for Lifecycle Information. For more information about service packs for these software releases, see Service Pack Lifecycle Support Policy.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, see the Microsoft Worldwide Information website, select the country in the Contact Information list, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Microsoft Support Lifecycle Policy FAQ.

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the February bulletin summary. For more information, see Microsoft Exploitability Index.

Affected Software Reference Count Vulnerability - CVE-2013-0076 Aggregate Severity Rating
Windows 7
Windows 7 for 32-bit Systems Important  Elevation of Privilege Important
Windows 7 for 32-bit Systems Service Pack 1 Important  Elevation of Privilege Important
Windows 7 for x64-based Systems Important  Elevation of Privilege Important
Windows 7 for x64-based Systems Service Pack 1 Important  Elevation of Privilege Important
Windows Server 2008 R2
Windows Server 2008 R2 for x64-based Systems Important  Elevation of Privilege Important
Windows Server 2008 R2 for x64-based Systems Service Pack 1 Important  Elevation of Privilege Important
Windows Server 2008 R2 for Itanium-based Systems Important  Elevation of Privilege Important
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 Important  Elevation of Privilege Important
Server Core installation option
Windows Server 2008 R2 for x64-based Systems (Server Core installation) Important  Elevation of Privilege Important
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) Important  Elevation of Privilege Important

Reference Count Vulnerability - CVE-2013-0076

An elevation of privilege vulnerability exists when the Windows CSRSS improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the local system. 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-2013-0076.

Mitigating Factors for Reference Count Vulnerability - CVE-2013-0076

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

  • An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability.

Workarounds for Reference Count Vulnerability - CVE-2013-0076

Microsoft has not identified any workarounds for this vulnerability.

FAQ for Reference Count Vulnerability - CVE-2013-0076

What is the scope of the vulnerability?
This is an elevation of privilege vulnerability.

What causes the vulnerability?
The vulnerability is caused when the Windows CSRSS improperly handles objects in memory.

What is the Windows Client/Server Runtime Subsystem (CSRSS)?
The Windows Client/Server Runtime Subsystem (CSRSS) is the user-mode portion of the Win32 subsystem (with Win32.sys being the kernel-mode portion). It is responsible for handling console windows, creating and/or deleting threads. It is an essential subsystem that must be running at all times.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the local system. 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 correcting the way that the Windows CSRSS handles objects in memory.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
Yes. This vulnerability has been publicly disclosed. It has been assigned Common Vulnerability and Exposure CVE-2013-0076.

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 website 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, "MS12-001"), you can add all 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) lets administrators scan local and remote systems for missing security updates as well as common security misconfigurations. For more information, see Microsoft Baseline Security Analyzer.

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

Software MBSA
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1 Yes
Windows 7 for x64-based Systems and Windows 7 for x64-based Systems Service Pack 1 Yes
Windows Server 2008 R2 for x64-based Systems and Windows Server 2008 R2 for x64-based Systems Service Pack 1 Yes
Windows Server 2008 R2 for Itanium-based Systems and Windows Server 2008 R2 for Itanium-based 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 see 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 System Center Configuration Manager (All Supported Versions)
Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1 Yes Yes
Windows 7 for x64-based Systems and Windows 7 for x64-based Systems Service Pack 1 Yes Yes
Windows Server 2008 R2 for x64-based Systems and Windows Server 2008 R2 for x64-based Systems Service Pack 1 Yes Yes
Windows Server 2008 R2 for Itanium-based Systems and Windows Server 2008 R2 for Itanium-based 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. 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 uses WSUS 3.0 for detection of updates. For more information, see System Center.

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 Windows Vista, a Windows Update, a Microsoft Security Update, or a new version of Windows Internet Explorer in your environment.

Security Update Deployment

Affected Software

For information about the specific security update for your affected software, click the appropriate link:

Windows 7 (all editions)

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

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-KB2790113-x86.msu /quiet
For all supported x64-based editions of Windows 7:\ Windows6.1-KB2790113-x64.msu /quiet
Installing without restarting For all supported 32-bit editions of Windows 7:\ Windows6.1-KB2790113-x86.msu /quiet /norestart
For all supported x64-based editions of Windows 7:\ Windows6.1-KB2790113-x64.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 2790113
Registry Key Verification Note A registry key does not exist to validate the presence of this update.

Deployment Information

Installing the Update

When you install this security update, the installer checks whether one or more of the files that are being updated on your system have previously been updated by a Microsoft hotfix.

For more information about the terminology that appears in this bulletin, such as hotfix, see Microsoft Knowledge Base Article 824684.

This security update supports the following setup 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.

Note For more information about the wusa.exe installer, see "Windows Update Stand-alone Installer" in the TechNet article, Miscellaneous Changes in Windows 7.

Verifying That the Update Has Been Applied

  • Microsoft Baseline Security Analyzer

    To verify that a security update has been applied to an affected system, you may be able to use the Microsoft Baseline Security Analyzer (MBSA) tool. See the section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.

  • File Version Verification

    Because there are several editions of Microsoft Windows, the following steps may be different on your system. If they are, see your product documentation to complete these steps.

    1. Click Start and then enter an update file name in the Search box.
    2. When the file appears under Programs, right-click the file name and click Properties.
    3. On the General tab, compare the file size with the file information tables provided in the bulletin KB article.
      Note Depending on the edition of the operating system, or the programs that are installed on your system, some files that are listed in the file information table may not be installed.
    4. You can also click the Details tab and compare information, such as file version and date modified, with the file information tables provided in the bulletin KB article.
      Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.
    5. Finally, you can also click the Previous Versions tab and compare file information for the previous version of the file with the file information for the new, or updated, version of the file.

Windows Server 2008 R2 (all editions)

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

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 x64-based editions of Windows Server 2008 R2:\ Windows6.1-KB2790113-x64.msu /quiet
For all supported Itanium-based editions of Windows Server 2008 R2:\ Windows6.1-KB2790113-ia64.msu /quiet
Installing without restarting For all supported x64-based editions of Windows Server 2008 R2:\ Windows6.1-KB2790113-x64.msu /quiet /norestart
For all supported Itanium-based editions of Windows Server 2008 R2:\ Windows6.1-KB2790113-ia64.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 2790113
Registry Key Verification Note A registry key does not exist to validate the presence of this update.

Deployment Information

Installing the Update

When you install this security update, the installer checks whether one or more of the files that are being updated on your system have previously been updated by a Microsoft hotfix.

For more information about the terminology that appears in this bulletin, such as hotfix, see Microsoft Knowledge Base Article 824684.

This security update supports the following setup 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.

Note For more information about the wusa.exe installer, see "Windows Update Stand-alone Installer" in the TechNet article, Miscellaneous Changes in Windows 7.

Verifying That the Update Has Been Applied

  • Microsoft Baseline Security Analyzer

    To verify that a security update has been applied to an affected system, you may be able to use the Microsoft Baseline Security Analyzer (MBSA) tool. See the section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.

  • File Version Verification

    Because there are several editions of Microsoft Windows, the following steps may be different on your system. If they are, see your product documentation to complete these steps.

    1. Click Start and then enter an update file name in the Start Search box.
    2. When the file appears under Programs, right-click the file name and click Properties.
    3. On the General tab, compare the file size with the file information tables provided in the bulletin KB article.
      Note Depending on the edition of the operating system, or the programs that are installed on your system, some files that are listed in the file information table may not be installed.
    4. You can also click the Details tab and compare information, such as file version and date modified, with the file information tables provided in the bulletin KB article.
      Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.
    5. Finally, you can also click the Previous Versions tab and compare file information for the previous version of the file with the file information for the new, or updated, version of the file.

Other Information

Acknowledgments

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

  • Max DeLiso for working with us on the Reference Count Vulnerability (CVE-2013-0076)

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 go to the active protections websites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Support

How to obtain help and support for this security update

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 (February 12, 2013): Bulletin published.

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