Active Directory: 10x Harder Than Entra

Key insights

• Active Directory (AD)
  Microsoft experts warn AD is far harder to defend because it is old, widely trusted, and full of legacy protocols like Kerberos and NTLM. Recent incident trends — a big jump in vulnerability disclosures and much faster exploit timelines — make on‑prem AD riskier today.
• Microsoft Entra ID
  Entra ID is built for the cloud with native controls such as Conditional Access, MFA, Privileged Identity Management, and Identity Protection. Teams should make Entra the primary identity control plane and keep AD only as a tightly limited dependency.
• Legacy attack surface
  On‑prem elements like domain trusts, older authentication protocols, Exchange servers, and forgotten devices (for example printers) expand the attack surface. These items often require special handling or migration to avoid persistent risk.
• Cloud‑native controls
  Follow rules for modern apps (prefer OAuth when possible), provision identities into Entra first from HR systems, avoid domain‑joining servers when not needed, and use Entra Domain Services only for apps that require LDAP or NTLM.
• Road to the Cloud playbook
  Use staged guidance to move from AD dependence to cloud identity: assess, plan, migrate, reduce on‑prem roles, and decommission last Exchange servers. Track progress with an identity pillar or Zero Trust workshop to keep work visible and accountable.
• Immediate practical steps
  Inventory AD risks, isolate and tier administrators, enable MFA and Conditional Access, apply just‑in‑time privileges, and write a clear plan to move off AD where possible. If you still rely on AD, document a timeline and milestones now.

Keywords

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