Best MFA Options for Microsoft 365, Ranked
Ranked by security: passkeys and FIDO2 hardware keys are strongest (phishing-resistant by design), Microsoft Authenticator with number matching is the right default for most organizations, and SMS codes are better than nothing but should be phased out — SIM-swapping and phishing kits defeat them routinely. Every Microsoft 365 tenant should enforce MFA for every user through Conditional Access, with no permanent exceptions.
- Passkeys/FIDO2: phishing-resistant, now practical for admins and high-value accounts
- Microsoft Authenticator with number matching: the right default — free, fast, resistant to MFA-fatigue attacks
- SMS/voice: acceptable transition method only; actively phase out
- App passwords and legacy authentication: disable — they bypass MFA entirely
- Enforcement belongs in Conditional Access policies, not per-user settings (which don't scale and hide gaps)
The rollout matters as much as the method — MFA projects fail on communication, not technology. The full article covers the phased enforcement approach that avoids help desk meltdown, handling shared mailboxes and service accounts, and why "MFA registered" and "MFA enforced" are dangerously different tenant states.
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