Critical Security Features to Enable in Microsoft 365

Part of the Education Series by Advisory 

Securing your Microsoft 365 environment is crucial for protecting company data, emails, and collaboration tools. Below are the most critical security settings and best practices every business should enable to reduce risk and maintain compliance.

1) Enforce Multi-Factor Authentication (MFA)

MFA is one of the most effective ways to protect accounts. Enable Microsoft Authenticator or FIDO2 security keys for all users. Admin accounts should always use a hardware-based MFA method for maximum protection.

2) Implement Strong Password & Identity Policies

• Require strong, unique passwords (minimum 12 characters).
• Consider Microsoft’s Passwordless authentication options to further reduce risk.

3) Audit and Manage User Accounts

• Regularly review user accounts for inactive or former employees.
• Assign appropriate licenses and roles, limiting admin privileges where possible.
• Use Azure AD Privileged Identity Management (PIM) for temporary admin access.
  

4) Harden Admin Accounts

• Use dedicated admin accounts instead of regular user accounts.
• Limit the number of global admins and enforce role-based access controls (RBAC).
• Enable alerts for admin changes or suspicious activity in the tenant.

5) Control Third-Party App Access

• Review and monitor all third-party apps connected to your Microsoft 365 tenant.
• Block or restrict access to apps that are unverified or unnecessary.
• Use Conditional Access policies to control who can access apps based on device, location, or risk level.

6) Secure Email & Anti-Phishing Protections

• Enable Exchange Online Protection (EOP) and Microsoft Defender for Office 365.
• Configure SPF, DKIM, and DMARC to prevent email spoofing.
• Turn on Safe Links and Safe Attachments for additional protection against phishing.

7) Implement Data Loss Prevention (DLP)

• Use DLP policies in Exchange, SharePoint, and OneDrive to prevent sensitive data leaks.
• Restrict sharing of confidential files outside trusted domains.
• Monitor sharing activity and configure alerts for policy violations.

8) Enable Conditional Access & Session Controls

• Use Azure AD Conditional Access to enforce policies based on user, device, location, or application risk.
• Require MFA for risky sign-ins or for access from untrusted devices.
• Limit session durations for sensitive applications.

9) Backup & Recovery Protections

Microsoft 365 protects data from hardware failure, but accidental deletion or ransomware can still occur. Use a third-party backup solution to safeguard emails, Teams files, SharePoint, and OneDrive data. Test restores regularly.

10) Security Monitoring & Alerts

• Enable Microsoft 365 Security & Compliance alerts for suspicious logins, mass deletions, or privilege changes.
• Assign someone to review alerts regularly and follow up on high-priority events.
  

11) Continuous Security Awareness Training

• Educate employees about phishing, social engineering, and safe file-sharing practices.
• Run simulated phishing campaigns periodically to reinforce learning.

Summary

By enabling these Microsoft 365 security features, businesses can significantly reduce the risk of data breaches, ransomware attacks, and account compromises. Focus on MFA, admin hardening, conditional access, DLP, and monitoring, and you’ll have a strong foundation for a secure Microsoft 365 environment.

If you’d like Advisory to perform a Microsoft Security Audit or help you implement these best practices, we’d be happy to support you.