A Microsoft 365 Security Checklist for Small Businesses

Microsoft 365 holds your email, files and identities - which makes it the number one target for attackers aiming at your business. The good news is that it includes strong security tools. The bad news is that many of them are off by default. This checklist covers the essentials every small business should have in place.

1. Turn on Multi-Factor Authentication (MFA)

This is the single most effective control you can enable. MFA stops the vast majority of account takeovers, because a stolen password alone is no longer enough to get in. Enable it for everyone, with no exceptions - especially admins.

2. Protect your admin accounts

Admin accounts are the keys to the kingdom. Lock them down:

• Use separate admin accounts, not your everyday login
• Enforce MFA on all admin accounts
• Limit how many global admins you have (fewer is safer)

3. Harden email against phishing

Email is the most common attack route. Configure anti-phishing and anti-spoofing protection, and make sure your domain has SPF, DKIM and DMARC set up. We cover this fully in securing Microsoft 365 email, and the human side in protecting your business from phishing.

4. Control external sharing

By default, files can often be shared widely. Review and tighten sharing settings in SharePoint and OneDrive so sensitive data isn't accidentally exposed to the public or unintended recipients.

5. Set up conditional access (where licensed)

On Business Premium and above, conditional access lets you control who can sign in, from where and on what devices - blocking risky logins automatically.

6. Don't rely on Microsoft for backup

A critical point people miss: Microsoft 365 is not a comprehensive backup. You still need your own backup against deletion, ransomware and departing staff. See does Microsoft 365 back up your data?

7. Keep devices and identities aligned

Your Microsoft 365 security is only as strong as the devices accessing it - including mobiles. Make sure devices are managed and up to date.

8. Monitor and review

Security isn't "set and forget". Review sign-in logs, the Microsoft Secure Score, and access regularly. This pairs with your broader IT security checklist.

Lock it down properly

Most breaches exploit basic gaps that this checklist closes. Our IT Support service configures and monitors Microsoft 365 security so you're protected, not just licensed. Request a callback for a security review.