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Summary

A denial of service vulnerability exists in the way that the Local Security Authority Subsystem Service (LSASS) handles authentication requests. An attacker who successfully exploited the vulnerability could cause a denial of service on the target system's LSASS service, which triggers an automatic reboot of the system. This security update addresses the vulnerability by changing the way that LSASS handles specially crafted authentication requests. 

To learn more about the vulnerability, see Microsoft Security Bulletin MS17-004.

More Information

Important

  • If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Additional information about this security update

The following articles contain additional information about this security update as it relates to individual product versions. The articles may contain known issue information.

  • 3216775 MS17-004: Description of the security update for Local Security Authority Subsystem Service: January 10, 2017

  • 3212642 January 2017 Security Only Quality Update for Windows 7 SP1 and Windows Server 2008 R2 SP1

  • 3212646 January 2017 Security Monthly Quality Rollup for Windows 7 SP1 and Windows Server 2008 R2 SP1

More Information

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-KB3216775-x86.msu

For all supported x64-based editions of Windows Server 2008:
Windows6.0-KB3216775-x64.msu

For all supported Itanium-based editions of Windows Server 2008:
Windows6.0-KB3216775-ia64.msu

Installation switches

See Microsoft Knowledge Base Article 934307

Restart requirement

You must restart the system after you apply this security update.

Removal information

WUSA.exe does not support uninstalling updates. To uninstall an update that is installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates, and then select from the list of updates.

File information

See Microsoft Knowledge Base Article 3216775

Registry key verification

Note This update does not add a registry key to validate its installation.

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-KB3212642-x86.msu
Security only

For all supported 32-bit editions of Windows 7
Windows6.1-KB3212646-x86.msu
Monthly rollup

For all supported x64-based editions of Windows 7:
Windows6.1-KB3212642-x64.msu
Security only

For all supported x64-based editions of Windows 7:
Windows6.1-KB3212646-x64.msu
Monthly rollup

Installation switches

See Microsoft Knowledge Base Article 934307

Restart requirement

You must restart the system after you apply this security update.

Removal information

To uninstall an update that is installed by WUSA, use the /Uninstall setup switch or click Control Panel, and then click System and Security. Under Windows Update, click View installed updates, and then select from the list of updates.

File information

See Microsoft Knowledge Base Article 3212642
See Microsoft Knowledge Base Article 3212646

Registry key verification

Note This update does not add a registry key to validate its installation.

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-KB3212642-x64.msu
Security only

For all supported x64-based editions of Windows Server 2008 R2:
Windows6.1-KB3212646-x64.msu
Monthly rollup

For all supported Itanium-based editions of Windows Server 2008 R2:
Windows6.1-KB3212642-ia64.msu
Security only

For all supported Itanium-based editions of Windows Server 2008 R2:
Windows6.1-KB3212646-ia64.msu
Monthly rollup

Installation switches

See Microsoft Knowledge Base Article 934307

Restart requirement

You must restart the system after you apply this security update.

Removal information

To uninstall an update that is installed by WUSA, use the /Uninstall setup switch or click Control Panel, and then click System and Security. Under Windows Update, click View installed updates, and then select from the list of updates.

File information

See Microsoft Knowledge Base Article 3212642
See Microsoft Knowledge Base Article 3212646

Registry key verification

Note This update does not add a registry key to validate its installation.


Help for installing updates: Support for Microsoft Update

Security solutions for IT professionals: TechNet Security Troubleshooting and Support

Help for protecting your Windows-based computer from viruses and malware: Virus Solution and Security Center

Local support according to your country: International Support

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