Password Expiration with AAD connect Password hash sync

ThomasK007,

I try to give you a detailed answer.

Until you have the EnforceCloudPasswordPolicyForPasswordSyncedUsers disabled (which is the default), an Azure AD user coming from on-premise AD (synced by AAD Connect) has its account password set to Never Expire.

"Password expiration policy

If a user is in the scope of password hash synchronization, by default the cloud account password is set to Never Expire.

You can continue to sign in to your cloud services by using a synchronized password that is expired in your on-premises environment. Your cloud password is updated the next time you change the password in the on-premises environment."

Reference: https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-password-hash-synchronization#public-preview-of-the-enforcecloudpasswordpolicyforpasswordsyncedusers-feature | Microsoft Docs

Once you enable the EnforceCloudPasswordPolicyForPasswordSyncedUsers feature and set the PasswordPolicies attribute to None (instead of DisablePasswordExpiration), the expiration time for an Azure AD user should be calculated referring to read-only attribute LastPasswordChangeTimestamp (you can retrieve it by using the Get-MsolUser cmdlet), depending on expiration policy.

Now if you have AAD Connect with password hash sync, same password expiration policy set on both Azure AD and on-premise AD (e.g. 90 days), every time a password is changed on-premise AD, pwdlastset attribute is updated, the password itself synced with Azure AD and the LastPasswordChangeTimestamp updates accordingly - so they both expires at same time (maybe few  minutes off); if you also have the password writeback functionality in place (link: https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-sspr-writeback | Microsoft Docs) the behavior described above works when the password is change from Azure AD and synced back to on-premise AD.

It should be right (please, can someone else confirm that ?)

I hope I was clear.

Bye,

Luca