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Microsoft Security Bulletin MS13-050 - Important

Vulnerability in Windows Print Spooler Components Could Allow Elevation of Privilege (2839894)

Published: June 11, 2013 | Updated: December 16, 2013

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 when an authenticated attacker deletes a printer connection. An attacker must have valid logon credentials and be able to log on to exploit this vulnerability.

This security update is rated Important for all supported editions of Windows Vista, Windows Server 2008, Windows 7, Windows Server 2008 R2, Windows 8, Windows Server 2012, and Windows RT. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by correcting how the Windows Print Spooler allocates memory when a printer connection is deleted. 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.

Knowledge Base Article

Knowledge Base Article 2839894
File informationYes
SHA1/SHA2 hashesYes
Known issuesYes

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 SystemMaximum Security ImpactAggregate Severity RatingUpdates Replaced
Windows Vista
Windows Vista Service Pack 2
(2839894)
Elevation of PrivilegeImportantNone
Windows Vista x64 Edition Service Pack 2
(2839894)
Elevation of PrivilegeImportantNone
Windows Server 2008
Windows Server 2008 for 32-bit Systems Service Pack 2
(2839894)
Elevation of PrivilegeImportantNone
Windows Server 2008 for x64-based Systems Service Pack 2
(2839894)
Elevation of PrivilegeImportantNone
Windows Server 2008 for Itanium-based Systems Service Pack 2
(2839894)
Elevation of PrivilegeImportantNone
Windows 7
Windows 7 for 32-bit Systems Service Pack 1
(2839894)
Elevation of PrivilegeImportant2769369 in MS13-001
Windows 7 for x64-based Systems Service Pack 1
(2839894)
Elevation of PrivilegeImportant2769369 in MS13-001
Windows Server 2008 R2
Windows Server 2008 R2 for x64-based Systems Service Pack 1
(2839894)
Elevation of PrivilegeImportant2769369 in MS13-001
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1
(2839894)
Elevation of PrivilegeImportant2769369 in MS13-001
Windows 8
Windows 8 for 32-bit Systems
(2839894)
Elevation of PrivilegeImportantNone
Windows 8 for 64-bit Systems
(2839894)
Elevation of PrivilegeImportantNone
Windows Server 2012
Windows Server 2012
(2839894)
Elevation of PrivilegeImportantNone
Windows RT
Windows RT[1]
(2839894)
Elevation of PrivilegeImportantNone
Server Core installation option
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
(2839894)
Elevation of PrivilegeImportantNone
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
(2839894)
Elevation of PrivilegeImportantNone
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
(2839894)
Elevation of PrivilegeImportant2769369 in MS13-001
Windows Server 2012 (Server Core installation)
(2839894)
Elevation of PrivilegeImportantNone

[1]This update is available via Windows Update.

 

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

I am running Windows Server 2008 (Server Core installation), Windows Server 2008 R2 (Server Core installation), or Windows Server 2012 (Server Core installation), which are listed in the Affected Software table. Why am I not being offered the 2839894 update? 
The 2839894 update is only offered to systems running a Server Core installation option of Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012 when the Printing-ServerCore-Role setting is enabled.

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

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 June bulletin summary. For more information, see Microsoft Exploitability Index.

Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected SoftwarePrint Spooler Vulnerability - CVE-2013-1339Aggregate Severity Rating
Windows Vista
Windows Vista Service Pack 2
(2839894)
Important 
Elevation of Privilege
Important
Windows Vista x64 Edition Service Pack 2
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2008
Windows Server 2008 for 32-bit Systems Service Pack 2
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2008 for x64-based Systems Service Pack 2
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2008 for Itanium-based Systems Service Pack 2
(2839894)
Important 
Elevation of Privilege
Important
Windows 7
Windows 7 for 32-bit Systems Service Pack 1
(2839894)
Important 
Elevation of Privilege
Important
Windows 7 for x64-based Systems Service Pack 1
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2008 R2
Windows Server 2008 R2 for x64-based Systems Service Pack 1
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1
(2839894)
Important 
Elevation of Privilege
Important
Windows 8
Windows 8 for 32-bit Systems
(2839894)
Important 
Elevation of Privilege
Important
Windows 8 for 64-bit Systems
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2012
Windows Server 2012
(2839894)
Important 
Elevation of Privilege
Important
Windows RT
Windows RT
(2839894)
Important 
Elevation of Privilege
Important
Server Core installation option
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
(2839894)
Important 
Elevation of Privilege
Important
Windows Server 2012 (Server Core installation)
(2839894)
Important 
Elevation of Privilege
Important

An elevation of privilege vulnerability exists in the way that Microsoft Windows Print Spooler handles memory when a printer is deleted.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-1339.

Mitigating Factors

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 to exploit this vulnerability.

Workarounds

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

  • Disable the Print Spooler service

    Disabling the Print Spooler service will help protect the affected system from attempts to exploit this vulnerability. To disable the Print Spooler service, perform the following steps.

    Interactive method:

    Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

    1. Click Start, click Run, type regedit, and then click OK.
    2. In Registry Editor, expand the following registry location:

      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\

    3. Select Print Spooler, and then click the File menu and select Export.
    4. In the Export Registry File dialog, type spooler_configuration_backup.reg and click Save.
    5. Double-click the registry DWORD entry named Start, change its value to 4, and then click OK.
    6. Run the following command at a command prompt running as an administrator:

      sc stop spooler

    Using a managed deployment script:

    1. Create a back-up copy of the registry keys using a managed deployment script with the following command:

      regedit /e spooler_configuration_backup.reg HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\spooler

    2. Create a text file named Disable_spooler.reg with the following contents:

      Windows Registry Editor Version 5.00

      [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Spooler]
      "Start"=dword:00000004

    3. Run the registry script created in step 2 on the target system by using the following command:

      Regedit /s Disable_spooler.reg

    4. Run the following command at a command prompt running as an administrator:

      sc stop spooler

    Impact of workaround. Print-related components will not function properly; printing will be disabled.

    How to undo the workaround. 

    To undo the workaround if applied using the interactive method:

    1. Click Start, click Run, type regedit, and then click OK.
    2. Click the File menu and select Import.
    3. In the Import Registry File dialog box select the registry backup file you created (spooler_configuration_backup.reg) and then click Open.

    To undo the workaround if applied using the managed deployment script, run the following command at a command prompt running as an administrator:

    Regedit /s spooler_configuration_backup.reg

FAQ

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

What causes the vulnerability? 
This vulnerability is caused when the Windows Print Spooler does not properly free memory when a printer connection is deleted.

What is the Print Spooler service ? 
The Print Spooler service is an executable file that is installed as a service. The spooler is loaded when the operating system starts, and it continues to run until the operating system is shut down. The Print Spooler service manages the printing process, which includes such tasks as retrieving the location of the correct printer driver, loading that driver, spooling high-level function calls into a print job, and scheduling print jobs. When the tasks for a particular print job are complete, the Print Spooler service passes the job to the print router. For more information, see How Network Printing Works.

What might an attacker use the vulnerability to do? 
An attacker who successfully exploited this vulnerability could run arbitrary code on a user's system with system privileges. An attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts.

How could an attacker exploit the vulnerability? 
An authenticated attacker could exploit the vulnerability by deleting a printer connection.

What systems are primarily at risk from the vulnerability? 
Workstations and servers are primarily at risk from this vulnerability.

What does the update do? 
The update addresses the vulnerability by correcting how the Windows Print Spooler allocates memory when a printer connection is deleted.

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

Several resources are available to help administrators deploy security updates. 

  • Microsoft Baseline Security Analyzer (MBSA) lets administrators scan local and remote systems for missing security updates and common security misconfigurations. 
  • Windows Server Update Services (WSUS), Systems Management Server (SMS), and System Center Configuration Manager (SCCM) help administrators distribute security updates. 
  • The Update Compatibility Evaluator components included with Application Compatibility Toolkit aid in streamlining the testing and validation of Windows updates against installed applications. 

For information about these and other tools that are available, see Security Tools for IT Pros

Affected Software

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

Windows Vista (all editions)

Reference Table

The following table contains the security update information for this software.

Security update file names For all supported 32-bit editions of Windows Vista:
Windows6.0-KB2839894-x86.msu
For all supported x64-based editions of Windows Vista:
Windows6.0-KB2839894-x64.msu
Installation switches See Microsoft Knowledge Base Article 934307
Restart requirement Yes, you must restart your system after you apply this security update.
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 2839894
Registry key verification Note A registry key does not exist to validate the presence of this update.

Windows Server 2008 (all editions)

Reference Table

The following table contains the security update information for this software.

Security update file names For all supported 32-bit editions of Windows Server 2008:
Windows6.0-KB2839894-x86.msu
For all supported x64-based editions of Windows Server 2008:
Windows6.0-KB2839894-x64.msu
For all supported Itanium-based editions of Windows Server 2008:
Windows6.0-KB2839894-ia64.msu
Installation switches See Microsoft Knowledge Base Article 934307
Restart requirement Yes, you must restart your system after you apply this security update.
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 2839894
Registry key verification Note A registry key does not exist to validate the presence of this update.

Windows 7 (all editions)

Reference Table

The following table contains the security update information for this software.

Security update file name For all supported 32-bit editions of Windows 7:
Windows6.1-KB2839894-x86.msu
For all supported x64-based editions of Windows 7:
Windows6.1-KB2839894-x64.msu
Installation switches See Microsoft Knowledge Base Article 934307
Restart r equirement Yes, you must restart your system after you apply this security update.
Removal i nformation 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 i nformation See Microsoft Knowledge Base Article 2839894
Registry k ey v erification Note A registry key does not exist to validate the presence of this update.

Windows Server 2008 R2 (all editions)

Reference Table

The following table contains the security update information for this software.

Security update file name For all supported x64-based editions of Windows Server 2008 R2:
Windows6.1-KB2839894-x64.msu
For all supported Itanium-based editions of Windows Server 2008 R2:
Windows6.1-KB2839894-ia64.msu
Installation switches See Microsoft Knowledge Base Article 934307
Restart requirement Yes, you must restart your system after you apply this security update.
Removal i nformation 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 i nformation See Microsoft Knowledge Base Article 2839894
Registry k ey v erification Note A registry key does not exist to validate the presence of this update.

Windows 8 (all editions)

Reference Table

The following table contains the security update information for this software.

Security update file name For all supported 32-bit editions of Windows 8:
Windows8-RT-KB2839894-x86.msu
For all supported 64-bit editions of Windows 8:
Windows8-RT-KB2839894-x64.msu
Installation switches See Microsoft Knowledge Base Article 934307
Restart requirement Yes, you must restart your system after you apply this security update.
Removal i nformation To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, click Windows Update, and then under See also, click Installed updates and select from the list of updates.
File i nformation See Microsoft Knowledge Base Article 2839894
Registry k ey v erification Note A registry key does not exist to validate the presence of this update.

Windows Server 2012 (all editions)

Reference Table

The following table contains the security update information for this software.

Security update file name For all supported editions of Windows Server 2012:
Windows8-RT-KB2839894-x64.msu
Installation switches See Microsoft Knowledge Base Article 934307
Restart requirement Yes, you must restart your system after you apply this security update.
Removal i nformation To uninstall an update installed by WUSA, use the /Uninstall setup switch or click Control Panel, click System and Security, click Windows Update, and then under See also, click Installed updates and select from the list of updates.
File i nformation See Microsoft Knowledge Base Article 2839894
Registry k ey v erification Note A registry key does not exist to validate the presence of this update.

Windows RT (all editions)

The following table contains the security update information for this software.

Deployment This update is available via Windows Update only.
R estart Requirement Yes, you must restart your system after you apply this security update.
Removal Information Click Control Panel, click System and Security, click Windows Update, and then under See also, click Installed updates and select from the list of updates.
File Information See Microsoft Knowledge Base Article 2839894

Other Information

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 (June 11, 2013): Bulletin published.
  • V1.1 (December 16, 2013): Revised bulletin to announce a detection change to correct an offering issue for Windows RT (2839894). This is a detection change only. There were no changes to the update files. Customers who have successfully installed the update do not need to take any action.

Built at 2014-04-18T13:49:36Z-07:00

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