MS16-100: Description of the security update for Secure Boot: August 9, 2016

Applies to: Windows 10Windows 10, version 1511Windows 10, version 1607 More

Summary


This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow security feature bypass if an attacker installs an affected boot manager and bypasses Windows security features.

To learn more about the vulnerability, see Microsoft Security Bulletin MS16-100.

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Important

  • All future security and non-security updates for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 require update 2919355 to be installed. We recommend that you install update 2919355 on your Windows RT 8.1-based, Windows 8.1-based, or Windows Server 2012 R2-based computer so that you receive future updates.
  • 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.

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Known issues in this security update

  • When you try to install this security update, you may receive an error message that resembles the following:
     
    The update is not applicable to your computer

    Each Windows version requires a Servicing Stack Update (SSU). If you install updates by using Windows Update, Windows Server Update Services (WSUS), or the Microsoft Update Catalog, an SSU is automatically installed as part of the update. If you receive this error message, and if security update 3172729 is not already installed, you must install the corresponding SSU.
    OS Version SSU KB #
    Windows Server 2016 TP5 3173423
    Windows Server 2012 3173426
    Windows 10 Version 1511 3173428
    Windows 10 3173427
    Windows 8.1 or Windows Server 2012 R2 3173424
  • If you are running Windows 10 Version 1607 (Anniversary Edition), the Hyper-V firmware will already have the TP5 boot manager blacklisted.

    For example, when you set up Hyper-V on a Windows 10 Version 1607-based system, if you then create a Windows Server 2016 TP5-based virtual machine (VM), the VM does not start.

    To resolve this issue, follow these steps:
     
    1. Open the Hyper-V Manager, right-click the VM, and then select Settings.
    2. In the navigation pane, select Security.
    3. In the details pane, select Microsoft UEFI Certificate Authority in the Template list.
    4. In the details pane, click to clear the Enable Secure Boot check box, and then click OK.

      Enable Secure Boot

       
    After you have installed TP5 on the VM and installed security update 3172729, re-enable secure boot. To do this, follow these steps:
    1. Open the Hyper-V Manager, right-click the VM, and then select Settings.
    2. In the navigation pane, select Security.
    3. In the details pane, click to select the Enable Secure Boot check box.
    4. In the details pane, select Microsoft Windows in the Template list, and then click OK

How to obtain and install the update


Method 1: Windows Update

This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to turn on automatic updating, see
Get security updates automatically.

Note For Windows RT 8.1, this update is available through Windows Update only.

Method 2: Microsoft Update Catalog

To get the stand-alone package for this update, go to the Microsoft Update Catalog website.
 

Method 3: Microsoft Download Center

For Windows 8.1, Windows Server 2012 R2 and Windows Server 2012, you can obtain the stand-alone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.

Click the download link in Microsoft Security Bulletin MS16-100 that corresponds to the version of Windows that you are running.

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How to obtain help and support for this security update

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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