Endpoint Security Hardening in 2026: A Practical Checklist for Busy IT Teams

[For IT Pros]

If you're responsible for laptops, desktops, and mobiles in 2026, you’re not just "keeping the antivirus updated" anymore. You’re defending a moving target of hybrid workers, AI-supported attacks, and devices that live outside the office network most of their life.

This is a practical, opinionated endpoint hardening checklist you can actually implement. Use it as a baseline to review your current build, tighten the gaps, and standardise your estate.

1. Start With a Secure Baseline, Not Manual Tinkering

1.1 Standardise on Modern OS and Enforcement

If you’re still supporting Windows 10 as a primary platform in 2026, you’re burning time. Aim for:

  • Windows: Windows 11 23H2 or later, managed via Intune or ConfigMgr co-management.
  • macOS: Current or -1 major version via MDM (Intune, Jamf, Kandji, etc.).
  • Mobile: iOS/iPadOS/Android Enterprise with full device or work profile management.

Action: Create a single "supported OS" list and attach it to your Conditional Access / compliance policies. Block (or at least warn) for anything outside that list.

1.2 Use Security Baselines as Your Starting Point

Don’t handcraft 400 settings if Microsoft, CIS, and NCSC have already done the heavy lifting.

  • In Intune: use the latest Microsoft Security Baselines for Windows 11, Edge, and Defender.
  • Map your hardening against CIS Level 1 for general users and Level 2 for admin / privileged devices.

Action: In Intune > Endpoint security > Security baselines, deploy a pilot baseline to IT devices first. Document any settings you relax and why.

2. Lock Down Identity and Local Privilege

2.1 Remove Local Admin by Default

Most ransomware and "IT oops" moments start with someone having too many rights on their device.

  • Default rule: No local admin for standard users, no exceptions "because they’re senior".
  • Use Privileged Access Workstations (PAWs) for admins with strict policies.

Intune example: Use an Account protection policy or a PowerShell script to reset the local Administrators group on join:

# Remove all current local admins except built-ins
$keep = @('Administrator', 'Administrators')
Get-LocalGroupMember -Group 'Administrators' | Where-Object {
    $keep -notcontains $_.Name
} | ForEach-Object { Remove-LocalGroupMember -Group 'Administrators' -Member $_ -ErrorAction SilentlyContinue }

# Add a designated support group from Azure AD
net localgroup Administrators "AZUREAD\\Support Local Admins" /add

2.2 Strong Device Identity and Join Type

Decide what each device is in your world: corporate, BYOD, or shared. Then treat it accordingly.

  • Corporate Windows: Enforce Azure AD join or Hybrid join, no more standalone devices.
  • BYOD: App protection policies and conditional access; no full device join for personal machines.

Action: In Azure AD > Devices > Device settings, restrict "Users may join devices" to a specific group. Stop the wild-west of random joins.

3. Harden Disk, Boot, and Core OS Protections

3.1 Encrypt Everything by Default

In 2026, unencrypted corporate endpoints are an incident waiting to be announced.

  • Windows: BitLocker with XTS-AES 256, TPM-only for standard devices, TPM+PIN for PAWs.
  • macOS: FileVault enforced via MDM, keys escrowed centrally.

Intune BitLocker profile (Windows 11 example):

  • OS drive encryption method: XTS-AES 256
  • Require device to be TPM capable: Yes
  • Store recovery information in Azure AD: Yes
  • Silently enable BitLocker: Yes (for Autopilot joined devices)

3.2 Secure Boot, TPM, and Firmware

Modern attacks increasingly hook into boot and firmware. Make sure you’re using the hardware you’re already paying for.

  • Enforce Secure Boot and TPM 2.0 for all new Windows hardware.
  • Standardise on business-grade devices that support firmware management via your vendor’s update service (HP, Dell, Lenovo portals, or Windows Update for Business).

Action: Add a hardware standard to your procurement policy: "Must support Secure Boot, TPM 2.0, and vendor API/MDM firmware management".

4. Defensive Stack: Defender, EDR, and Attack Surface Reduction

4.1 Treat Defender as Your Primary EDR (If You’re in M365)

Defender for Endpoint is mature enough that running three AVs isn't giving you more security, just more support tickets.

  • Use Defender for Endpoint P2 or equivalent EDR across Windows, macOS, mobile, and servers.
  • Integrate alerts into your SIEM/SOAR (Sentinel, Splunk, etc.) and build at least basic triage automation.

PowerShell quick check (Windows):

Get-MpComputerStatus | Select-Object AMServiceEnabled, AntispywareEnabled, RealTimeProtectionEnabled, IoavProtectionEnabled

4.2 Enable Attack Surface Reduction (ASR) Rules

ASR rules stop the "day-one" nonsense: Office spawning PowerShell, malware abusing LOLBins, that sort of thing.

  • Start in Audit mode for 2–4 weeks.
  • Review events, tune exceptions, then switch to Block.

Example high-value ASR rules to enforce:

  • Block all Office applications from creating child processes.
  • Block executable content from email and webmail clients.
  • Block credential stealing from LSASS.

Action: In Microsoft 365 Defender > Settings > Endpoints > Attack surface reduction, start a dedicated "pilot" policy group for IT, then widen.

4.3 Application Control: From Allow-All to Allow-What-You-Need

You can’t secure endpoints if anything can run on them.

  • Windows: Use Microsoft Defender Application Control (MDAC) in audit mode first, then switch critical groups to enforced.
  • macOS: Use MDM to restrict kernel/system extensions and signed apps for sensitive groups.

Action: Start with blocking obvious high-risk file types from user-writable paths (e.g. .exe, .js, .vbs from Downloads) before you go full allow-list.

5. Browser, Web, and Email Protection

5.1 Standardise Browsers and Policies

Attackers love outdated, random browsers with 27 unpatched extensions.

  • Pick a primary browser: Edge or Chrome for most orgs.
  • Use Intune configuration profiles to control updates, extensions, passwords, and sync.

Edge policy examples (via Intune or ADMX):

  • BrowserAddProfileEnabled = Disabled (block personal profiles on corporate devices)
  • PasswordManagerEnabled = Disabled if you have an enterprise password manager
  • ExtensionInstallBlocklist = * with an allowlist for approved extensions

5.2 Web and Email Filtering

Most initial compromise still comes from links and attachments.

  • Use Defender for Office 365 or equivalent for Safe Links and Safe Attachments.
  • Deploy a secure web gateway or use Microsoft Defender for Cloud Apps for shadow IT control.

Action: Create a "high-risk" URL category (new domains, parked domains, dynamic DNS, etc.) and force those to open in Isolated browser / Application Guard where possible.

6. Endpoint Configuration Hygiene: Patching, Apps, and Local Services

6.1 Patch OS and Third-Party Apps Aggressively

If you patch Windows but leave Java, browsers, and VPN clients months behind, you’re still wide open.

  • Use Windows Update for Business (WUfB) with deadline policies (e.g. 7 days + 2 day grace, auto-restart out of hours).
  • Patch third-party apps via Intune Win32 apps, Winget, or a tool like Patch My PC Enterprise.

Winget update script (example):

$apps = @('Google.Chrome', 'Adobe.Acrobat.Reader.64-bit', 'Zoom.Zoom')
foreach ($app in $apps) {
    winget upgrade --id $app --accept-package-agreements --accept-source-agreements
}

6.2 Disable Unnecessary Services and Legacy Protocols

Legacy protocols are still being exploited in 2026 because nobody gets paid to turn them off.

  • Disable SMBv1 everywhere. Confirm SMB signing where relevant.
  • On Windows clients, disable legacy services like Fax, Remote Registry, and unnecessary optional features.

PowerShell snippet:

Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol -NoRestart -ErrorAction SilentlyContinue
Stop-Service RemoteRegistry -ErrorAction SilentlyContinue
Set-Service RemoteRegistry -StartupType Disabled

7. Device Visibility, Compliance, and Response

7.1 Know What You Actually Have

You can’t harden what you don’t see. In most orgs, "shadow endpoints" are bigger than shadow IT.

  • Use Defender for Endpoint or your EDR to auto-onboard new devices.
  • Regularly export device inventories and compare against HR / asset registers.

Action: Set up a monthly job that flags devices without check-ins in the last 30 days and pushes them to an "investigate or decommission" queue.

7.2 Compliance Policies That Actually Bite

A compliance policy nobody enforces is just documentation.

  • Create Intune compliance policies that include: encryption required, OS version minimum, no jailbroken/rooted, active EDR, Secure Boot on.
  • Wire them into Conditional Access: non-compliant = no access to M365 and critical apps.

Example Conditional Access approach:

  • Policy 1: "Block non-compliant devices" – all cloud apps, all users except break-glass.
  • Policy 2: "Require compliant or approved client app" for Exchange/SharePoint.

7.3 Have a Clear Endpoint Incident Playbook

When a device is compromised, you don’t want five people arguing in Teams about what to do.

  • Document a "Malicious Endpoint" runbook: isolate, collect, analyse, rebuild, restore access.
  • Use EDR "isolate device" capability as your default first action for high-confidence alerts.

Action: Store your endpoint incident playbook in your IT knowledge base and run a tabletop exercise twice a year using a realistic laptop compromise scenario.

8. Quick 30-Day Endpoint Hardening Plan

If this all feels like a lot, break it into four weekly sprints and actually ship something.

  • Week 1: Define supported OS list, deploy baseline encryption policies, confirm Secure Boot/TPM requirements for new kit.
  • Week 2: Remove local admin by default, roll out Defender for Endpoint to any remaining unmanaged devices, start ASR rules in audit mode.
  • Week 3: Standardise browsers, enforce automatic updates, start third-party patching, disable obvious legacy services (SMBv1, Remote Registry).
  • Week 4: Tighten Intune compliance policies, wire them into Conditional Access, finalise your endpoint incident response playbook.

Next step: Pick one section from this checklist and implement it on a small pilot group this week. Don’t wait for a "big project" – incremental hardening across your endpoints is what will actually reduce your risk this year.