How Password hash Sync (PHS) works in Azure?

 

Password Hash Sync (PHS) is a feature of Azure Active Directory (Azure AD) Connect, which synchronizes on-premises Active Directory user account passwords to Azure AD. Here's how PHS works in Azure:

1. Initial Configuration: After installing and configuring Azure AD Connect in your on-premises environment, you can enable Password Hash Sync as one of the synchronization options during setup. This option instructs Azure AD Connect to synchronize password hashes from your on-premises Active Directory to Azure AD.

2. Password Hash Synchronization: When a user changes their password in on-premises Active Directory, the password hash (a cryptographic representation of the password) is computed and stored in the Active Directory database. Azure AD Connect periodically synchronizes these password hashes to Azure AD using a secure, encrypted connection.

3. Hash Synchronization Frequency: By default, password hash synchronization occurs every 2 minutes. However, you can configure the synchronization frequency based on your organization's requirements.

4. Hash Synchronization Process: During the synchronization process, Azure AD Connect extracts the password hash values from the on-premises Active Directory database and securely transmits them to Azure AD using Transport Layer Security (TLS) encryption. Azure AD stores these password hashes securely and associates them with the corresponding user accounts.

5. Hash Verification: When a user attempts to sign in to Azure AD (e.g., using Office 365 services), Azure AD compares the password hash provided by the user during sign-in with the stored password hash for the user's account. If the hashes match, the user is authenticated, and access is granted.

6. Security Measures: To ensure the security of password hashes during synchronization and storage, Azure AD uses industry-standard encryption algorithms and security best practices. Password hashes are encrypted both in transit and at rest, and additional security measures are implemented to protect against unauthorized access and brute-force attacks.

7. User Authentication: Once authenticated, users can access Azure AD-integrated services and applications using their on-premises Active Directory credentials without needing to re-enter their passwords. This provides a seamless single sign-on (SSO) experience for users across on-premises and cloud environments.

Overall, Password Hash Sync simplifies user authentication and access management in hybrid environments by synchronizing on-premises Active Directory passwords to Azure AD, enabling users to access cloud-based resources using their existing credentials.