5 Essential Microsoft 365 Security Best Practices for Small Businesses
· 5 min read
Microsoft 365 gives small businesses enterprise-grade tools — but default settings rarely match your risk profile. IT directors should prioritize these five controls first.
1. Enforce Multi-Factor Authentication (MFA)
Require MFA for all users, especially administrators. Phishing-resistant methods (FIDO2, Microsoft Authenticator with number matching) significantly reduce account takeover risk.
2. Implement Conditional Access
Block legacy authentication, require compliant devices, and restrict sign-ins from unexpected geographies. Start with a report-only policy, then enforce.
3. Harden Email with Defender for Office 365
Enable anti-phishing policies, safe links, safe attachments, and impersonation protection for executives and finance roles.
4. Limit Privileged Roles
Use Privileged Identity Management (PIM) where available. Global Admin accounts should be cloud-only, named, and rarely used day-to-day.
5. Enable Unified Audit Logging
Turn on audit logging and forward logs to a SIEM or Microsoft Sentinel for retention beyond default periods. You can't investigate what you didn't record.