Microsoft 365 is at the centre of many small businesses: email, files, Teams, calendars and day-to-day collaboration. That also makes it an obvious target for attackers. The good news is that a handful of sensible controls can remove a large amount of unnecessary risk.
These are eight checks we regularly recommend for small and growing businesses. Some options depend on your Microsoft 365 licence, but the principles apply to almost every environment.
1. Make sure MFA is enforced everywhere
Multi-factor authentication should protect every user account, not just directors or administrators. A stolen password should not be enough to access email, SharePoint or Teams. Where possible, use modern authentication methods such as authenticator app prompts rather than relying only on SMS.
2. Separate administrator accounts from everyday accounts
People who administer Microsoft 365 should not use a privileged admin account for normal email and web browsing. Keeping administration separate reduces the chance that a compromised everyday account immediately gives an attacker high-level access.
3. Remove old or unnecessary sign-in methods
Legacy sign-in methods and unused protocols can bypass newer security controls. Review what your users and applications genuinely need, and disable older authentication methods where they are no longer required.
4. Use Conditional Access where your licence supports it
Conditional Access can add rules around how, where and from what type of device people sign in. For businesses using licences that include it, this can be used to block risky sign-ins, require MFA in the right situations and apply stronger controls to administrator accounts.
5. Review email protection and anti-phishing controls
Email remains one of the most common routes into a business. Check anti-phishing, impersonation, spoofing and malicious-link protection rather than assuming the default configuration is enough. Your setup should also reflect any third-party email security product you use so controls complement each other instead of creating gaps or unnecessary duplication.
6. Check external sharing in SharePoint and OneDrive
External sharing is useful, but it should be deliberate. Review who can create sharing links, whether anonymous links are allowed, and how long external access remains valid. Old shared links can become a quiet security risk if nobody reviews them.
7. Have a proper offboarding process
When someone leaves, simply changing their password is not enough. Their sessions should be revoked, access removed, mailbox and OneDrive data handled correctly, licences reviewed and any shared credentials replaced. A consistent checklist prevents former staff accounts lingering unnoticed.
8. Do not treat Microsoft 365 as your only backup
Microsoft provides resilience and retention features, but businesses should still decide how they would recover from accidental deletion, malicious deletion, ransomware or a compromised account. An independent Microsoft 365 backup gives you another recovery path when the original tenant data is no longer available in the way you need it.
Security is stronger when the controls work together
No single setting makes Microsoft 365 secure. The strongest results come from combining identity protection, sensible permissions, email security, endpoint protection, backup and ongoing monitoring.
If you are unsure how your tenant is configured, ML Services can review your existing setup and identify practical improvements without changing things simply for the sake of it. See our Microsoft 365 support, cybersecurity services and managed IT support, or contact us to discuss your current environment.
Photo: Ed Hardie via Unsplash.