Microsoft 365 Certified: Administrator ExpertImplement and manage Microsoft Entra IDEasy

A company is planning to implement Microsoft Entra ID for identity management. They have an existing on-premises Active Directory Domain Services (AD DS) environment. The security team has a strict requirement that no user passwords should ever be stored or synchronized to the cloud, even in hashed form. They also require that users authenticate directly against the on-premises AD DS environment for all cloud services. Which Microsoft Entra Connect authentication method should you recommend to meet these requirements?

  1. AFederation with AD FS
  2. BMicrosoft Entra Seamless Single Sign-On (Seamless SSO)
  3. CPass-through Authentication (PTA)
  4. DPassword Hash Synchronization (PHS)
Show answer & explanation

Correct answer: C. Pass-through Authentication (PTA)

Pass-through Authentication (PTA) is designed to validate user passwords against the on-premises Active Directory directly, without storing any password hashes in Microsoft Entra ID. This fulfills the security team's requirement for no cloud password storage.

Why the other options are wrong

  • A. Federation with AD FS also meets the requirement, but PTA is a simpler, more cloud-native solution for this specific scenario when only authentication is needed.
  • B. Seamless SSO is a feature that provides a single sign-on experience but is not an authentication method itself; it can be used with PHS or PTA.
  • D. PHS synchronizes a hash of the user's password to Microsoft Entra ID, which violates the 'no passwords in the cloud' requirement.

Pass-through Authentication (PTA)

Microsoft Entra Pass-through Authentication allows users to sign in to both on-premises and cloud-based applications using the same passwords. It validates users' passwords directly against their on-premises Active Directory.

  • No password hashes stored in cloud.
  • Requires Lightweight Microsoft Entra Connect Authentication Agents.
  • Provides a seamless sign-in experience for users.

Memory trick: PTA: Pass-Through, Passwords Stay At Home

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