MVT Systems — Managed IT, Microsoft 365 & Cybersecurity South Africa
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Why MFA Alone Is Not Enough to Protect Microsoft 365

MFA stops the easy attacks. It does not stop the determined ones. This is what every Microsoft 365 tenant needs on top.

Why MFA Alone Is Not Enough to Protect Microsoft 365 — MVT Systems article illustration

Multi-factor authentication is one of the highest-ROI controls a business can deploy. But MFA on its own is a single layer — and attackers have moved past it. Adversary-in-the-middle phishing kits steal session tokens; SIM swaps bypass SMS codes; legacy authentication protocols ignore MFA entirely.

Conditional Access

Conditional Access in Microsoft Entra ID lets you require MFA only when something looks risky, and block sign-ins outright when the signal is bad. The minimum policy set we deploy on every tenant:

  • Require MFA for all users.
  • Block legacy authentication protocols.
  • Require compliant or hybrid-joined devices for sensitive apps.
  • Block sign-ins from countries the business doesn't operate in.
  • Require MFA & password change on high-risk sign-ins.

Impossible travel and risky sign-ins

Entra ID Protection scores every sign-in for risk. Pair that with Conditional Access and you can quietly block or step-up impossible travel events, anonymous IPs and leaked credential reuse.

Legacy authentication

Older protocols like IMAP, POP and SMTP AUTH never see your MFA prompt. Attackers use them constantly. Block them at the tenant level and exception only what you genuinely need.

Admin accounts

Global Admins should be dedicated accounts, used from hardened devices, with phishing-resistant MFA (FIDO2 or Windows Hello for Business). Day-to-day work should never happen on an admin account.

Device compliance

Microsoft 365 data leaves your tenant the moment it lands on an unmanaged device. Intune compliance policies are the difference between “authenticated” and “trusted.”

Put it all together

Our Microsoft 365 support practice deploys this baseline as part of a security baseline review. For higher-risk environments we layer Microsoft Sentinel on top.

Book a Microsoft 365 security review →

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