MFA Is Enabled. Is Your Microsoft 365 Environment Actually Secure?

Having MFA enabled does not mean your Microsoft 365 environment is fully secured.

For many small and midsize businesses, enabling multifactor authentication feels like a major cybersecurity milestone.

MFA adds an important layer of protection to Microsoft 365 accounts by requiring another method of verification during sign-in. Microsoft includes MFA among its top security recommendations for small and midsize businesses.

But there is an important distinction: Having MFA enabled does not mean your Microsoft 365 environment is fully secured.

Think of MFA as one layer of a larger security strategy. The strength of your Microsoft 365 environment also depends on how administrators are protected, how users and devices are allowed to connect, how email threats are handled, and whether suspicious activity is being monitored.

For a 10-to-50+ person company without a dedicated internal IT or cybersecurity team, those settings can be especially easy to overlook.

MFA Protects the Login. What Protects Everything Around It?

Microsoft’s own security guidance for small and midsize businesses goes beyond MFA. Its recommendations include protecting administrator accounts, applying security policies, protecting devices, securing email and using additional controls depending on Microsoft 365 licensing.

Ask yourself: Is our Microsoft 365 environment configured securely around MFA?

1. Are Administrator Accounts Properly Protected?

Administrator accounts can make significant changes to your Microsoft 365 environment, so they deserve additional attention. Microsoft specifically recommends protecting admin accounts and using roles with the fewest permissions necessary rather than relying unnecessarily on highly privileged Global Administrator accounts.

Ask yourself:

• Who currently has administrative access?
• Does every person with admin privileges actually need them?
• Are administrator roles reviewed regularly?
• Are administrative accounts protected appropriately?

2. Has Legacy Authentication Been Addressed?

MFA is most useful when the surrounding authentication environment is configured appropriately. One of the recommendations in SII’s existing O365 Security Checklist is enabling Conditional Access policies to block legacy authentication. Microsoft’s Conditional Access capabilities allow organizations with appropriate licensing to set more granular requirements around access, while security defaults provide baseline protections for organizations without those capabilities.

3. Are Access Decisions Based on More Than a Password?

Modern Microsoft 365 security can consider more than whether somebody knows the correct password. Depending on licensing and configuration, organizations can use Microsoft Entra and Conditional Access to apply stronger controls to access. Microsoft specifically identifies Conditional Access as an option for organizations with more stringent access requirements. Internally, SII’s Microsoft 365 baseline work has also focused on areas including MFA, Conditional Access, location restrictions and device-related controls, with the important caveat that licensing and operational impact need to be evaluated for each client.

5. Are the Devices Accessing Company Information Protected?

Microsoft 365 security extends beyond users and email. Microsoft recommends protecting devices that access company data. Its SMB security guidance specifically references mobile-device management as well as Microsoft Intune and Microsoft Defender for Business capabilities available with Microsoft 365 Business Premium. That matters for a 20- to 50-person organization where employees may access Microsoft 365 from company laptops, phones and other devices.

Microsoft 365 Security Checklist for Business Owners

You don’t need to be a Microsoft administrator to ask the right questions.

The Bigger Question: Who Is Responsible for Your Microsoft 365 Security?

• Who reviews Microsoft 365 security settings?
• Who decides when Microsoft introduces new security capabilities?
• Who determines whether a license change would improve protection?
• Who investigates unusual sign-ins?
• Who makes sure access gets removed when an employee leaves?
• And who is accountable for making sure all of those pieces continue working together?

SII’s internal strategy already emphasizes Microsoft 365 tenant reviews and hardening around identity protection, Conditional Access, Defender, data loss prevention and information protection. And SII’s operational work goes further, using Microsoft 365 tenant baselines and reviewing those controls against individual customer licensing, configurations and workflows rather than assuming one configuration fits every organization.

MFA Is the Starting Point

If you’ve already enabled MFA, you’re heading in the right direction.

The next step isn’t buying another tool simply because it promises more security. It’s understanding the Microsoft 365 environment you already have:

What’s protected?
What’s configured correctly?
What’s missing?
What’s included in your licensing?
And who is responsible for keeping it secure?

Not sure what surrounds your MFA?

Ask SII for a Microsoft 365 Security Review.

We’ll help evaluate the controls around your Microsoft 365 environment, identify areas that deserve attention and help you understand what the next step should be.