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

[For IT Pros]

If an attacker lands on one laptop in your estate today, how far can they go from there? In 2026, with AI-assisted phishing and commodity RaaS kits everywhere, "basic" endpoint security is no longer enough. The good news: most organisations can dramatically raise the bar with a clear, opinionated hardening checklist and some discipline.

Think of this as the baseline I like to implement when I walk into a new environment as an IT Director. It’s not a perfect zero-day-proof fortress; it’s a realistic, defendable standard that your team can actually run and maintain.

1. Start With a Clean, Enforced Baseline

1.1 Enrol and standardise every device

If it’s not enrolled and managed, it’s a liability. You cannot harden what you don’t see.

  • Windows: Enrol everything in Intune (including hybrid-joined). Block manual local account creation via policy.
  • macOS: Use ABM + Intune/Jamf. Require MDM enrolment for Wi‑Fi/line-of-business access.
  • Mobiles: Use Intune MDM or at least MAM with app protection for BYOD.

Key policy idea: Create an Azure AD (Entra ID) Conditional Access policy that blocks access to Microsoft 365 from devices that are not compliant:

// Pseudo-policy (Entra ID Conditional Access)
Assignments:
  Users: All staff (exclude break-glass)
  Cloud apps: Office 365, Exchange Online, SharePoint Online
  Conditions: Any location
Grant:
  Require device to be marked as compliant

1.2 Use security baselines, then layer your rules

Don’t start from an empty sheet. Use vendor baselines as your floor, not your ceiling:

  • Apply the Microsoft Intune Security Baseline (latest) to all Windows 11 endpoints.
  • Use CIS Benchmarks as reference, but prioritise compatibility over “Level 2 everywhere”.
  • For macOS, start with your MDM’s hardened baseline (e.g., Jamf CIS template) and adapt.

Track intentional deviations. Store them in a simple markdown or Confluence page: Endpoint Baseline - Exceptions Log with who/why/expiry date.

2. Lock Down Identity, Local Privileges, and Session Hygiene

2.1 Remove local admin from humans

Local admin on a user’s primary device is still the most common root cause I see in real incidents. Remove it by default, then provide controlled elevation.

  • Block local admin assignment in your Intune device configuration.
  • Use Endpoint Privilege Management (Intune EPM), LAPS-based JIT, or tools like BeyondTrust to grant short-lived elevation.

Example: Intune Local User Group policy (Settings Catalog)

Local Users and Groups > Local Group (Administrators)
  - Members: <IT Support Group SID>, <Break-glass account SID>
  - Action: Replace

2.2 Harden credentials and session storage

Assume that one browser session token will be stolen at some point. Limit the damage.

  • Force WebAuthn/FIDO2 or platform biometrics (Windows Hello, macOS Touch ID) for all staff MFA.
  • Enable Entra ID sign-in risk policies to challenge suspicious sessions with step-up auth.
  • Disable password saving in browsers for corporate accounts via GPO/Intune config.

Example: Force strong auth with a Conditional Access policy

Assignments:
  Users: All staff
  Cloud apps: All
Conditions:
  Sign-in risk: Medium and above
Grant:
  Require phishing-resistant MFA (FIDO2 / certificate-based)

2.3 Disable legacy protocols and weak auth

In 2026, there’s no excuse for NTLM and basic auth still being quietly on.

  • Disable NTLM where possible and at least restrict to known servers.
  • Confirm Basic auth is fully disabled in Exchange Online and all SMTP relay flows are modernised.
  • Enforce OAuth and modern auth for all apps; create a small exception list with a deprecation date.

3. OS, Disk, and Surface Hardening

3.1 Full disk encryption everywhere

Laptops get lost. People still leave devices in taxis. Encrypt everything and prove it in reports.

  • Windows: BitLocker with XTS-AES 256, TPM + PIN for high-risk users (admins, finance).
  • macOS: FileVault enforced via MDM, escrow recovery keys centrally.
  • Mobiles: Require device encryption in Intune compliance policies.

Example: Simple BitLocker policy (Intune)

Endpoint security > Disk encryption
  OS drive:
    Encryption: Enabled
    Algorithm: XTS-AES 256
    Startup authentication: TPM (standard), TPM + PIN (admins)
  Fixed data drives: Encrypt
  Recovery keys: Store in Entra ID / Intune

3.2 Application control: stop anything from running anywhere

Modern malware loves living off the land. You need guardrails on what can run, from where.

  • Deploy Application Control for Business (WDAC) via Intune for Windows: start in audit mode, then enforce in phases.
  • Require signed code for kernel/driver installs; block unsigned and unknown device drivers.
  • On macOS, require notarised apps, and restrict kernel/system extensions via MDM-approved list.

Example: Minimal WDAC allow policy (excerpt)

<Allow>
  <FilePublisherCondition>
    <PublisherName>O=Microsoft Corporation, L=Redmond, S=Washington, C=US</PublisherName>
    <ProductName>*</ProductName>
    <BinaryName>*</BinaryName>
  </FilePublisherCondition>
  <FilePathCondition>C:\\Program Files\\CompanyApps\\*</FilePathCondition>
</Allow>

Combine this with blocking execution from user-writable paths like %TEMP%, %USERPROFILE%\Downloads and external USB drives.

3.3 Reduce attack surface with ASR and kernel protections

For Windows, Attack Surface Reduction (ASR) rules are still one of the highest-ROI controls.

  • Start with audit mode on a pilot group, monitor via Defender portal for 2–4 weeks.
  • Then enforce a core set globally, keep a small exception policy for dev/legacy teams.

Example: Core ASR rules to enforce (PowerShell)

# Example using PowerShell (Defender)
$rules = @(
  'D4F940AB-401B-4EFC-AADC-AD5F3C50688A', # Block Office from creating child processes
  '3B576869-A4EC-4529-8536-B80A7769E899', # Block Office from creating executable content
  '75668C1F-73B5-4CF0-BB93-3ECF5CB7CC84', # Block Office apps from injecting code into other processes
  '26190899-1602-49E8-8B27-EB1D0A1CE869', # Block credential stealing from LSASS
  '5BEB7EFE-FD9A-4556-801D-275E5FFC04CC'  # Block execution of potentially obfuscated scripts
)

foreach($rule in $rules){
  Add-MpPreference -AttackSurfaceReductionRules_Ids $rule -AttackSurfaceReductionRules_Actions Enabled
}

On macOS, enable System Integrity Protection (SIP), runtime protections, and restrict developer tools to developer groups only.

4. Browser, Email, and Cloud App Protections

4.1 Standardise browsers and harden them

Random browser sprawl makes policy enforcement nearly impossible. Pick one main browser, maybe two at most.

  • Standard: Edge or Chrome, managed via Intune/Chrome Enterprise.
  • Force auto-update, disable sideloaded/unsigned extensions, and only allow from the managed web store.
  • Block dangerous APIs (e.g., USB, serial) unless needed, using browser policies.

Example: Edge extension allow-list (Intune ADMX)

Microsoft Edge > Extensions
  Control which extensions are installed:
    - Block all
    - Allow specific IDs: 
       1) uBlock Origin ID
       2) Password manager ID
       3) Company SSO helper ID

4.2 Use modern email filtering plus local controls

Even with excellent cloud filters, some phish and BEC attempts still land. Layer endpoint protections on top.

  • Enable Defender for Office 365 / equivalent: Safe Links, Safe Attachments, impersonation protection.
  • Configure Outlook/Teams to flag external senders and potential lookalike domains.
  • Disable automatic execution of macros from the internet and enforce Mark-of-the-Web honouring.

Example: Block internet macros (Intune)

Administrative Templates > Microsoft Office 365 > Security Settings
  Block macros from running in Office files from the Internet: Enabled

4.3 Control data movement to SaaS and personal accounts

Endpoints are often the last choke point before data leaves the organisation.

  • Enable Endpoint DLP (Defender / equivalent) to monitor and block sensitive data to personal cloud apps and USB.
  • Use App Control / CASB to distinguish corporate vs personal instances (e.g. OneDrive, Google Drive).
  • Block copy/paste and downloads from high-risk apps/sites on unmanaged devices via CA and reverse proxies.

5. EDR, Logging, and Response Readiness

5.1 Deploy a full EDR stack to every endpoint

AV alone is not incident response. You need telemetry, hunting, and remote actions.

  • Standardise on a single EDR (e.g., Microsoft Defender for Endpoint, CrowdStrike, SentinelOne) across Windows, macOS, Linux.
  • Block uninstall or tampering via MDM and OS protections.
  • Verify sensor health and coverage in monthly reports: devices with last-seen >7 days should be treated as missing.

5.2 Centralise and normalise logs

When something goes wrong, missing logs cost you more than missing controls.

  • Send EDR, OS security logs, and key app logs (VPN, identity, proxies) into your SIEM (Sentinel, Splunk, etc.).
  • Implement basic detections: local admin creation, new scheduled tasks, new services, WDAC/ASR blocks, unusual PowerShell usage.
  • Keep at least 6–12 months of security-relevant logs for investigations and trend analysis.

Example: Simple KQL for suspicious PowerShell (Sentinel)

DeviceProcessEvents
| where FileName =~ "powershell.exe" or FileName =~ "pwsh.exe"
| where ProcessCommandLine has_any ("-enc", "-EncodedCommand", "DownloadString", "IEX")
| summarize count() by DeviceName, AccountName, bin(Timestamp, 1h)
| order by count_ desc

5.3 Pre-build your response playbooks

When a real incident happens, you won’t have time to argue about process. Decide now.

  • Define levels of severity (e.g., P1–P4) and what each one triggers (on-call, exec comms, legal, etc.).
  • Prepare EDR playbooks: isolate device, collect triage package, kill process, block hash, reset tokens.
  • Test with quarterly tabletop exercises and update your docs after each run.

6. Practical Rollout Plan: 90-Day Hardening Sprint

6.1 Phase 1 (Weeks 1–4): Visibility and quick wins

  • Enrol all devices in Intune/MDM and deploy EDR sensors.
  • Enable BitLocker/FileVault and enforce device compliance policies.
  • Deploy email protections (Safe Links/Attachments) and block internet macros.

6.2 Phase 2 (Weeks 5–8): Privileges and attack surface

  • Remove local admin from all non-IT users; implement controlled elevation.
  • Enable ASR and WDAC / application control in audit mode, monitor impact.
  • Standardise browsers and push hardened configurations and extension allow-lists.

6.3 Phase 3 (Weeks 9–12): Enforcement and detection

  • Move ASR and app control to enforcement for most users; keep a clearly defined exception group.
  • Complete SIEM integrations, deploy core detections, and tune noisy rules.
  • Run a simulated incident (e.g., assumed ransomware on one endpoint) and exercise your playbooks.

Next Action: Score Your Current Endpoint Posture

Before you start changing policies, quickly score yourself across these areas: identity & local admin, disk encryption, app control & ASR, browser/email hardening, EDR & logging. Use a simple 0–3 scale (0 = not in place, 3 = fully enforced and monitored) and calculate an average score.

Your very next step: pick the lowest-scoring area and design a 30-day mini-project just for that. Small, focused improvements, executed properly, will give you more real security than a huge "endpoint transformation" initiative that never lands.