8 Actionable Tips to Secure Your Microsoft 365 Environment

As a small business owner, you’ve probably already seen the immense benefits that Microsoft 365 brings to your company—whether it’s seamless collaboration, easy access to files, or the power of cloud services. But while Microsoft 365 offers a suite of powerful tools, ensuring it is secure is absolutely critical to protecting your business data and operations. After all, the last thing you want is for your sensitive data to be vulnerable to cyber threats.

Why Securing Microsoft 365 Matters

We always tell clients that securing M365 (Microsoft 365) is more than just trusting Microsoft’s built-in protections. While Microsoft does offer robust security features (including Security Defaults), many of them need to be configured properly to provide the best protection for your business.
Here are some best practices MTG recommend:

1. Enforce Multi-Factor Authentication (MFA)

Simply put – MFA is a must. By enabling it, you add an extra layer of security to your user accounts, which is critical since stolen credentials are one of the most common ways hackers gain access to business data. MFA is simple but incredibly effective. While basic per-user MFA is an option, a more effective approach is using Conditional Access. This method ensures MFA applies to all users, and can require stronger or phish-resistant forms of MFA such as Yubikey (or other hardware tokens).

Yubikey with NFC - important for securing Microsoft 365 — Hardware tokens such as YubiKey are considered a “phishing-resistant” form of MFA.

2. Monitor and Audit User Activity

We advise our clients to regularly review activity logs to spot unusual or suspicious activity, such as unexpected logins or MFA attempts. Microsoft 365 offers a built-in auditing feature that can be configured to alert you when something seems off. We recommend integrating this step into your regular security check-ups. Alternatively, consider a SIEM or MDR system that can continually monitor cloud activity.

3. Apply Microsoft Security Baselines (CIS & NIST)

Following CIS Benchmarks and NIST recommendations when setting up Microsoft 365 environments ensures a secure foundation. These benchmarks provide a comprehensive guide for configuring security settings in line with industry standards. If you’re not already familiar with these frameworks, it’s worth noting that they cover everything from password policies and device security to network settings.

Organisations that enable multi-factor authentication (MFA) can reduce the likelihood of identity-based attacks by 99.9%
Microsoft Security Team

4. Enable Conditional Access Policies

For businesses that want an extra layer of control, Conditional Access Policies are a game changer. Conditional Access allows you to grant or block access based on certain conditions, like location or device status. For example, you could block users from logging in if they’re on an unknown device or in a foreign country. This type of granular control helps us ensure that only authorised individuals access your business-critical data. (Conditional Access is included in M365 Business Premium, or Entra-ID P1)

5. Setup Advanced Threat Protection

Email is a key entry point for cyberattacks. Using Microsoft Defender for Office 365 can help block malicious attachments and phishing attempts before they reach your inbox. It’s an essential line of defence in preventing malware and ransomware. Enabling impersonation protection, phishing protection and tweaking some of the settings can further enhance protection.

6. Use Microsoft Secure Score

Microsoft provides a useful tool called Secure Score, which assesses your M365 environment and gives you actionable recommendations to improve security. It’s a great starting point to see where your setup might be falling short. Regularly review your Secure Score and prioritise the actions Microsoft recommends. You’ll not only make your systems more secure but also build resilience against emerging threats.

7. Train Your Employees

No matter how secure your infrastructure is, employees are often the weakest link. Conduct security awareness training regularly to educate them about the risks of phishing, social engineering, and poor password practices. Microsoft provides tools such as Attack Simulator that let you test your team’s readiness.

8. Back Up Critical Data

Despite all the security in place, you need to be prepared for the worst. Ensure that you have regular backups of your critical data (i.e. E-mail, Sharepoint, etc), both within M365, and on external backup solutions. While Microsoft 365 does provide native data redundancy, having additional backups can save your business in a disaster scenario.

Ready to Secure Your Microsoft 365 Environment?

Contact us today to get a free assessment of your current Microsoft 365 setup, and let us help you implement best practices that will keep your business safe.