Zero Trust Security for Small Businesses | M365 Guide
Zero trust is built on never trust, always verify. Instead of assuming everything inside your network is safe, zero trust verifies every access request regardless of origin. This guide explains how to apply zero trust practically in a small business Microsoft 365 environment.
The three zero trust principles
Quick wins you can do today
12-month roadmap
Month 1-2 (Foundation): MFA for all users, SSPR, block legacy auth, CA baseline policies
Month 3-4 (Devices): Intune enrolment, compliance policies, require compliant device for email
Month 5-6 (Identity): PIM for admin roles, Identity Protection, Named Locations
Month 7-8 (Email): DMARC to enforcement, Defender for Office 365, phishing simulation
Month 9-10 (Endpoint): ASR rules, BitLocker, Defender for Endpoint
Month 11-12 (Visibility): Microsoft Sentinel, analytics rules, incident response playbooks
Frequently Asked Questions
Zero trust replaces the traditional VPN. Users access apps directly via the internet with strong identity verification.
Yes. Microsoft 365 Business Premium includes most tools needed - Intune, Entra ID P1, Defender for Office 365 P1, and Conditional Access.
Perimeter security trusts everything inside the firewall. Zero trust assumes no implicit trust - every request is verified regardless of network location.