Entra ID Hardening: What to Fix First

A practical priority order for hardening Entra ID: legacy authentication, MFA, Conditional Access, PIM, guest accounts, and app registrations.

Start with the controls that block account takeover

Entra ID is the control plane for Microsoft 365. The first hardening pass should close the paths attackers use most often: legacy authentication, weak MFA coverage, excessive privileged access, and unmanaged guest access.

Priority 1: block legacy authentication

Legacy protocols can bypass modern MFA controls. Review sign-in logs, identify any remaining dependency, then block legacy authentication with Conditional Access after confirming business-critical exceptions.

Priority 2: enforce phishing-resistant MFA

Move beyond password-only accounts and weak SMS or voice methods. Use Microsoft Authenticator, passkeys, or FIDO2 where possible, and enforce MFA through Conditional Access rather than relying on user-level registration alone.

Priority 3: deploy a Conditional Access framework

A durable framework covers all users, all cloud apps, device state, location, sign-in risk, and break-glass access. Policies should be documented, tested, and staged before enforcement.

Priority 4: remove standing privileged access

Privileged Identity Management limits admin exposure by making role activation time-bound, auditable, and subject to MFA or approval. Standing Global Admin access should be the exception.