Azure AD Powershell – Token Lifetime Configuration for MFA

The default token expiry in Azure AD for ADAL clients (using Modern Authentication) is 14 days for single factor and multi factor authentication users. This can stretch up to 90 days as long as the user does not change their password, and they do not go offline for longer than 14 days.

This means that clients using Outlook or Skype for Business can perform MFA once and then remain signed in using their access token for up to 90 days before being required to authenticate using MFA. As you can imagine, this is not an ideal situation for multi-factor authentication as a compromised account could be accessed through a rich client application with no MFA for up to 90 days.

Until recently, this could not be modified. However Microsoft released Configurable Token Lifetime as a Preview feature quite recently. This allows for various properties to be controlled, giving administrators more granular control over token refresh and enforcing a more secure MFA policy.

The Azure team have provided a solid guide here: https://docs.microsoft.com/en-us/azure/active-directory/active-directory-configurable-token-lifetimes

To do this, you need the Azure AD Preview PowerShell module. Install this by running the following from a PowerShell prompt:

Install-Module -Name AzureADPreview 

Here is a sample policy I’ve configured which will change the MFA token lifetime to 12 hours. I’ve combined this with ADFS Claim Rules which only enforce MFA if the user is on the extranet and using particular applications:

New-AzureADPolicy -Definition @("{`"TokenLifetimePolicy`":{`"Version`":1, `"MaxAgeMultiFactor`":`"12:00:00`",`"AccessTokenLifetime`":`"04:00:00`"}}") -DisplayName OrganizationDefaultPolicyScenario -IsOrganizationDefault $true -Type TokenLifetimePolicy

This is  a much needed feature from the point of view of security controls, although keep in mind it is still in Preview!

 

 

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