Continuous Access Evaluation and working with tokens

Continuous access evaluation in Azure AD | Microsoft Docs

Access, ID, and SAML2

ID tokens are JSON web tokens (JWT). These ID tokens consist of a header, payload, and signature. The header and signature are used to verify the authenticity of the token, while the payload contains the information about the user requested by your client. The v1.0 and v2.0 ID tokens have differences in the information they carry. The version is based on the endpoint from where it was requested. While existing applications likely use the Azure AD endpoint (v1.0), new applications should use the “Microsoft identity platform” endpoint(v2.0).

ID tokens and SAML2 tokens default lifetime 1 hour and the minimum 10 and maximum 1 day.

JWTs (JSON Web Tokens)

These tokens are splitted in to three sections.

  • Header – Provides information about how to validate the token including information about the type of token and how it was signed.
  • Payload – Contains all of the important data about the user or app that is attempting to call your service.
  • Signature – Is the raw material used to validate the token.

Each piece is separated by a period (.) and separately Base64 encoded.

In example Federations Services uses JWT Tokens.

SAML 2.0 SSO

Single Sign-On (SSO) Workflow

If and most of the time when you have problems with ADFS sign-in and tokens, these ones will be really useful on debugging the tokens.

And Microsoft has provided also other Online and Offline debugging tools for saml and token related problems, thanks Microsoft!

https://adfshelp.microsoft.com/

Refresh tokens

Below you can see the Refresh token revocation methods.

ChangePassword-based cookiePassword-based tokenNon-password-based cookieNon-password-based tokenConfidential client token
Password expiresStays aliveStays aliveStays aliveStays aliveStays alive
Password changed by userRevokedRevokedStays aliveStays aliveStays alive
User does SSPRRevokedRevokedStays aliveStays aliveStays alive
Admin resets passwordRevokedRevokedStays aliveStays aliveStays alive
User revokes their refresh tokens via PowerShellRevokedRevokedRevokedRevokedRevoked
Admin revokes all refresh tokens for a user via PowerShellRevokedRevokedRevokedRevokedRevoked
Single sign-out on webRevokedStays aliveRevokedStays aliveStays alive

CAE

Continuous access evaluation (CAE) capable clients that negotiate CAE-aware sessions will see a long lived token lifetime (up to 28 hours)

And they keep the session open, regularly questioning that do I still need the connection or no.

The goal is for response to be near real time, but latency of up to 15 minutes may be observed because of event propagation time.

And the initial implementation of continuous access evaluation focuses on Exchange, Teams, and SharePoint Online.

And the following events are evaluated continuously.

  • User Account is deleted or disabled
  • Password for a user is changed or reset
  • Multi-factor authentication is enabled for the user
  • Administrator explicitly revokes all refresh tokens for a user
  • High user risk detected by Azure AD Identity Protection

In the future there will be more.

Conditional Access policy evaluation

Exchange Online, SharePoint Online, Teams, and MS Graph can synchronize key Conditional Access policies for evaluation within the service itself.

Scenarios supported.

Outlook WebOutlook Win32Outlook iOSOutlook AndroidOutlook Mac
SharePoint OnlineSupportedSupportedSupportedSupportedSupported
Exchange OnlineSupportedSupportedSupportedSupportedSupported
Office web appsOffice Win32 appsOffice for iOSOffice for AndroidOffice for Mac
SharePoint OnlineNot SupportedSupportedSupportedSupportedSupported
Exchange OnlineNot SupportedSupportedSupportedSupportedSupported
OneDrive webOneDrive Win32OneDrive iOSOneDrive AndroidOneDrive Mac
SharePoint OnlineSupportedSupportedSupportedSupportedSupported
Teams webTeams Win32Teams iOSTeams AndroidTeams Mac
Teams ServiceSupportedSupportedSupportedSupportedSupported
SharePoint OnlineSupportedSupportedSupportedSupportedSupported
Exchange OnlineSupportedSupportedSupportedSupportedSupported

Why to use?

  • User termination or password change/reset: User session revocation will be enforced in near real time.
  • Network location change: Conditional Access location policies will be enforced in near real time.
  • Token export to a machine outside of a trusted network can be prevented with Conditional Access location policies.

Token lifetime

Because risk and policy are evaluated in real time, clients that negotiate continuous access evaluation aware sessions no longer rely on static access token lifetime policies. This change means that the configurable token lifetime policy isn’t honored for clients negotiating CAE-aware sessions.

Token lifetime is increased to long lived, up to 28 hours, in CAE sessions. Revocation is driven by critical events and policy evaluation, not just an arbitrary time period. This change increases the stability of applications without affecting security posture.

If you aren’t using CAE-capable clients, your default access token lifetime will remain 1 hour. The default only changes if you configured your access token lifetime with the Configurable Token Lifetime (CTL) preview feature.

Final words

You should just enable it, there isn’t really no reason why you shouldn’t. The default setting inside your tenant is anyway the “Auto enable after GA” so it’s preferred to be enabled.

It helps your tokens to be flushed when credential leakage happen so you don’t have to do it manually.

You should, really.

And there is also another approach for keeping sessions nice and short and that is with Conditional Access policies. And not even allowing the options for users to save their logins.

And this is the setting it will override if you have it enabled.

That’s all, folks. Until the next time and then with Azure AD Identity Protection.

Author: Harri Jaakkonen

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