Microsoft releases new Security baseline (FINAL) for Windows 10 v1903 and Windows Server v1903

Download the content from
the Microsoft Security Compliance Toolkit
(click Download and select Windows 10 Version 1903 and Windows Server Version
1903 Security

Note that Windows Server version
1903 is Server Core only and does not offer a Desktop Experience (a.k.a.,
“full”) server installation option. In the past we have published baselines
only for “full” server releases – Windows Server 2016 and 2019. Beginning with
this release we intend to publish baselines for Core-only Windows Server
versions as well. However, we do not intend at this time to distinguish
settings in the baseline that apply only to Desktop Experience. When applied to
Server Core, those settings are inert for all intents and purposes.

This new Windows Feature
Update brings very few new Group Policy settings, which we list in the
accompanying documentation. This baseline recommends configuring only two of
those. However, we have made several changes to existing settings, including
some changes since the draft version of this baseline
that we published last month.

The changes from the Windows
10 v1809 and Windows Server 2019 baselines include:

  • Enabling the new “Enable svchost.exe mitigation
    options” policy, which enforces stricter security on Windows services
    hosted in svchost.exe, including that all binaries loaded by svchost.exe
    must be signed by Microsoft, and that dynamically-generated code is
    disallowed. Please pay special attention to this one as it might
    cause compatibility problems with third-party code that tries to use the
    svchost.exe hosting process, including third-party smart-card plugins.
  • Configuring the new App Privacy setting, “Let
    Windows apps activate with voice while the system is locked,” so that
    users cannot interact with applications using speech while the system is locked.
  • Disabling multicast name resolution (LLMNR) to
    mitigate server spoofing threats.
  • Restricting the NetBT NodeType to P-node,
    disallowing the use of broadcast to register or resolve names, also to
    mitigate server spoofing threats. We have added a setting to the custom
    “MS Security Guide” ADMX to enable managing this configuration setting
    through Group Policy.
  • Correcting an oversight in the Domain
    Controller baseline by adding recommended auditing settings for Kerberos
    authentication service.
  • Dropping the password-expiration policies that
    require periodic password changes. This change is discussed in further
    detail below.
  • Dropping the specific BitLocker drive
    encryption method and cipher strength settings. The baseline has been
    requiring the strongest available BitLocker encryption. We are removing
    that item for a few reasons. The default is 128-bit encryption, and our
    crypto experts tell us that there is no known danger of its being broken
    in the foreseeable future. On some hardware there can be noticeable
    performance degradation going from 128- to 256-bit. And finally, many
    devices such as those in the Microsoft Surface line turn on BitLocker by
    default and use the default algorithms. Converting those to use 256-bit
    requires first decrypting the volumes and then re-encrypting, which
    creates temporary security exposure as well as user impact.
  • Dropping the File Explorer “Turn off Data
    Execution Prevention for Explorer” and “Turn off heap termination on
    corruption” settings, as it turns out they merely enforce default
    behavior, as Raymond Chen describes here.

Additional changes that we
have adopted since publishing the draft version of this baseline include:

  • Dropping the enforcement of the default
    behavior of disabling the built-in Administrator and Guest accounts. We
    had floated this proposal at the time of the draft baseline, and have
    since decided to accept it. The change is discussed in more detail below.
  • Dropped a Windows Defender Antivirus setting
    that applies only to legacy email file formats.
  • Changed the Windows Defender Exploit Protection
    XML configuration to allow Groove.exe (OneDrive for Business) to launch
    child processes, particularly MsoSync.exe which is necessary for file
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