Password Hash Synchronization (PHS)

-

 

🔐 What is Password Hash Synchronization (PHS)?

Password Hash Synchronization is a method used in Azure AD Connect to sync password hashes from your on-premises Active Directory to Azure Active Directory (Microsoft 365 cloud).

🔁 It allows users to use the same password on-prem and in the cloud (single sign-on experience).

🧠 How It Works (Simplified):

  1. A user changes or sets their password in on-prem AD.

  2. Azure AD Connect takes a hashed version of the password (already hashed in AD), adds its own extra hash and salt.

  3. This double-hashed password is synced securely to Azure AD.

  4. When a user logs into Microsoft 365, Azure AD uses that hash to verify the password.

⚠️ The actual password is never sent or stored in plain text — it's always in a hashed and salted format.

📦 Why Use Password Hash Sync?

BenefitDescription
✅ Simple to set upNo need for extra servers like ADFS.
✅ Same password across systemsUsers don’t need to remember two passwords.
✅ Supports cloud authenticationAzure AD validates the login directly.
✅ Supports MFA + Conditional AccessWorks with modern security controls in Azure.
✅ Backup login methodIf on-prem goes down, users can still authenticate in the cloud.

🆚 Compared to Other Authentication Methods:

MethodAuth LocationNeeds On-Prem InfraMFA SupportResilience
Password Hash Sync (PHS)Cloud (Azure AD)❌ No (after sync)✅ Yes✅ High
Pass-through Auth (PTA)On-prem AD✅ Yes (agents)✅ Yes⚠️ Needs uptime
Federation (ADFS)On-prem ADFS✅ Yes (ADFS servers)✅ Yes⚠️ Complex

🔐 Is It Secure?

Yes — Microsoft never syncs the actual password.
It syncs a SHA-256 hashed version of the already-hashed NTLM password, plus adds a salt.

🧪 Real-life Use Case:

A company wants users to sign into Microsoft Teams, Outlook, and SharePoint using the same password they use for their company computers — but without maintaining a complex ADFS setup.

✅ Password Hash Sync is perfect.

Popular posts from this blog

Autodiscover

-
  "Autodiscovery" (or  Autodiscover , more precisely in Microsoft terms) is a service that automatically configures email clients, mainly Outlook, to connect to mailboxes without users having to enter all the settings manually. 💡  What is Autodiscover? Autodiscover  is a Microsoft Exchange service that provides configuration information to email clients (like Outlook or mobile devices) so they can set themselves up with minimal user input. 🔧  What Does Autodiscover Do? When a user enters just their  email address and password , Autodiscover helps the client automatically find: Mail server addresses (Exchange or Microsoft 365) Mailbox settings Calendar and contact URLs Offline address book (OAB) settings Outlook Anywhere settings Unified Messaging (if used) Internal and external URLs 🧠  How It Works (Simplified Flow): User opens Outlook and enters their email address + password. Outlook sends a request to the  Autodiscover service : Tries a few ...
Read more

Azure Active Directory (Azure AD)

-
  Azure Active Directory (Azure AD)  is Microsoft’s  cloud-based identity and access management service , which is the cloud counterpart to the traditional  on-premises Active Directory (AD) . While  Active Directory (AD)  is designed for managing users, groups, and devices within an organization's  internal network ,  Azure AD  extends this functionality to manage identities across cloud-based resources, applications, and services. Azure AD helps organizations manage user access to cloud services (like  Office 365 ,  Azure services ,  third-party apps , etc.) and provides features like  Single Sign-On (SSO) ,  Multi-Factor Authentication (MFA) , and more — all while maintaining security and compliance in the cloud. Key Differences Between Active Directory (AD) and Azure Active Directory (Azure AD): Deployment Location : AD  is  on-premises , running in an organization's internal network. Azure AD  is...
Read more

Active Directory (AD)

-
   Active Directory (AD)  is a  directory service  developed by Microsoft to manage and organize a network's resources, such as users, computers, printers, and other devices. It’s a central component in managing permissions, security, and access control across the entire network. AD allows admins to control who can access what within the network and apply policies and settings consistently. Here’s a more detailed breakdown of  Active Directory : Key Features of Active Directory: Directory Service : It acts as a  centralized database  for storing and managing directory information (like users, computers, groups, and resources). It uses  LDAP (Lightweight Directory Access Protocol)  for communication between client machines and the server. User Authentication and Authorization : Active Directory ensures  only authorized users  and  computers  can access the network resources. It enforces  user policies  (like ...
Read more