Microsoft 365
Beginner Guide
Security
Securing Microsoft 365: A Beginner's Guide
ThreatMate Team
Oct 15, 2022
4 min read
Getting Started with M365 Security
Microsoft 365 is powerful but complex. This guide covers the essential security settings every administrator should configure.
Priority 1: Authentication
Enable MFA The most important step. Enable MFA for: - All users (security defaults at minimum) - All administrators (Conditional Access preferred)
Block Legacy Authentication Legacy protocols bypass MFA. Block them: - Exchange ActiveSync (basic auth) - IMAP/POP3 - Older Office clients
Priority 2: Email Security
Configure Anti-Phishing Enable impersonation protection for executives and key staff.
Enable Safe Links and Safe Attachments Scan links and attachments in real-time.
Set Up DMARC Protect your domain from spoofing.
Priority 3: Data Protection
Review Sharing Settings Limit external and anonymous sharing.
Enable Audit Logging Essential for incident investigation.
Configure Alerts Set up notifications for suspicious activity.
Priority 4: Admin Security
Minimize Global Admins Use role-based access control.
Separate Admin Accounts Don't use admin accounts for daily work.
Review Permissions Regularly Remove unnecessary access.
Next Steps
This guide covers basics. For comprehensive security: - Use CISA's ScubaGear baseline - Consider Microsoft Defender for Office 365 - Implement Conditional Access policies
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