If you run Windows Server 2025 in production (on-prem, Azure, Azure Arc, “Adaptive Cloud”, homelab-with-a-budget — doesn’t matter), you need to understand “Microsoft Security Baselines for Windows Server 2025” and their lifecycle. Not “some settings we once configured in 2019 and never touched again”, but a repeatable, reviewable security posture.

Microsoft’s answer to that is the Windows Server 2025 Security Baseline, shipped through the Security Compliance Toolkit (SCT).

What a Microsoft security baseline is (and what it isn’t)

A Microsoft security baseline is a group of recommended configuration settings created from input across Microsoft engineering, product teams, partners, and customers. It’s meant to help you navigate the ocean of settings without playing “guess the secure value” for every knob.

Microsoft’s baseline principles are refreshingly pragmatic:

• Baselines assume a well-managed environment where standard users do not have admin rights.
• Microsoft enforces settings when they mitigate current threats and don’t create operational pain worse than the risk.
• They enforce defaults mainly when insecure states are realistically likely to happen.

What a baseline is not:

• Not a promise that you can click “apply baseline” and be done.
• Not a replacement for tiering, privileged access design, patching discipline, or monitoring.
• Not “one GPO to rule them all”.

It’s a starting point based on an industry best practice, so you can defend in front of auditors and operations.

Where you get the Windows Server 2025 baseline

Today, Microsoft ships Windows / Server baselines through the Security Compliance Toolkit (SCT) on the Microsoft Download Center.

SCT is not just “download a zip” — it’s a small ecosystem:

• Baselines (including Windows Server 2025, currently published as versioned packages)
• Tools:
  • Policy Analyzer (compare and diff GPO sets, export to Excel, compare against local policy/registry)
  • LGPO.exe (apply/export local policy; import from GPO backups, security templates, auditing CSV, registry.pol)
  • SetObjectSecurity and GPO→PolicyRules helpers

Download Link Microsoft Security Compliance Toolkit 1.0 : December 2025

Also worth knowing: the old Security Compliance Manager (SCM) is retired; SCT is the supported path now, and the packaging is intentionally lightweight (zips with GPO backups + docs + scripts).

What’s inside the baseline package (why it matters for GPO backup & compare)

Microsoft publishes baselines in consumable formats — specifically including Group Policy Object backup format — to enable faster deployment and easier management.

In practice, the Server baseline zip is designed for three things:

1. Read it (documentation/spreadsheets so you can see what will change)
2. Apply it (through GPO / domain, or via local mechanisms)
3. Compare it (baseline vs your current GPO backups, baseline v1 vs baseline v2, baseline vs local effective state)

That “GPO backup format” part is pure gold for the blog series I’m building here: it means we can treat baselines like code — export, commit, diff, review.

Stay current and use the latest Baselines

Microsoft Security Baselines for Windows Server 2025 announcement and the June 2025 revision give you a feel for the kinds of changes you’ll see:

January 2025 release called out changes in areas like account lockout, LSA, LAPS, Kerberos, Defender AV, Windows Update, and more. Link

The v2506 revision includes removals/cleanups and adjustments (and Microsoft explicitly states they plan more frequent revisions going forward). Link

Important: You need to understand the baseline for Windows OS is under development. You want to review the blog for latest updates and develop a “baseline as a lifecycle” mindset.

How do I use the baseline as a lifecycle

I want the baseline to be survive reality, so i treat it like a lifecycle, not a one-time import. During it’s lifecycle I want to download the current version and keep track of my changes.

Start clean: keep Microsoft’s baseline separate

Don’t copy baseline settings into your existing “Corporate Default GPO” monster. Never. Not even in your homelab.

Instead:

• Import baseline GPOs as their own GPOs
• Link them where appropriate (Member Servers vs Domain Controllers)
• Create a separate “Delta” GPO for your intentional deviations

Why? Because Microsoft is planning more frequent revisions for the Server 2025 baseline to keep pace with threats and new features. If you blend everything into one blob, updating becomes archaeology.

Validate in a lab / pilot OU

Microsoft explicitly warns that after applying a baseline, defaults and behaviors change — you must test before production.

Source: Evaluation guidance based on OSCconfig – If you haven’t head about OSConfig click here to read my guide.

Important: The reason I am writing this guide is simple. Most of my critical Severity 1 issues in the past have been tied to lack of monitoring or changes to Group Policies. That’s why I want to share how to backup, compare and restore Group Policies in the next guides. Validation and Testing is key and also learning how to recover / restore.

Document your deviations (the only part auditors actually love)

Your security posture is rarely “100% baseline”. There will be security or operation acceptance. Develop a naming convention with your Operational and Security teams. Create GPOs based on the needed exceptions and allow the IT Security to start tracking them on a 12 month cycle with the owner.

Limit exceptions to small groups or individual servers using GPO Item level Targeting or OU level assignments, i.e. based on my initial GPO guide use this naming convention <ENV>-<Side>-<Area>-<Purpose>-<Scope>

Example. Prod-Computer-Security-Ticket4711-Servers

For details on Item Level Targeting and how to link, please check my foundational full guide here.

Download the files required

For the next guides around Microsoft Security Baselines for Windows Server 2025 we will need to download at least the baseline and the Group Policy “PolicyAnalyzer” from here.

Test locally – LGPO to Apply baselines without AD

For lab validation, jump boxes, workgroup servers, or “I want to see what it breaks first”, LGPO.exe is extremely handy to get started with Microsoft Security Baselines for Windows Server 2025.

LGPO can:

• Import settings from GPO backups (and other formats)
• Export local policy to a GPO backup
• Work with registry.pol, security templates, auditing CSV, etc.

That local-export capability is underrated: you can apply something locally, then export the resulting state, and compare it like any other GPO backup.

Conclusion on Microsoft Security Baselines for Windows Server 2025

If you take one thing away from this: a security baseline is not a one-time hardening project. It’s a product with a release cadence. Windows Server 2025 baselines will keep changing — because the threat landscape keeps changing, and the platform keeps changing. So if your approach is “import once and never touch it again”, you’re not running a baseline. You’re running a snapshot from the past.

Treat the baseline like a lifecycle:

• Keep Microsoft’s baseline separate from your own “delta” GPOs
• Review baseline updates like you review patch notes
• Test, roll out, monitor, and document deviations on purpose

Important: Microsoft Security Baselines for Windows Server 2025 can introduce operational risk. That’s the trade-off. They tighten controls, change defaults, and occasionally break “we always did it this way”. But they’re still one of the best first lines of defence you can deploy quickly — especially if you want a security posture that is repeatable, auditable, and updatable without turning every change into archaeology.

This post is a foundation for my follow-up article on a GPO backup + compare article on hartiga.de — because the Microsoft Security Baselines for Windows Server 2025 is delivered in exactly the formats that make “baseline-as-code” with GPO backups actually practical.

If you have any questions please don’t hesitate to reach out to me on LinkedIn, Bluesky or check my newly created Adaptive Cloud community on Reddit.

LinkedIn: https://www.linkedin.com/in/andreas-hartig/
Bluesky: https://bsky.app/profile/hartiga.de
Adaptive Cloud community on Reddit: https://www.reddit.com/r/AdaptiveCloud/

Further reading around Microsoft Security Baselines for Windows Server 2025