New Active Directory Documents for IT Pros
I've seen several posts on the new "authentication assurance" feature coming in Windows Server 2008 R2. The term we decided to go with is authentication mechanism assurance because it is actually the authentication mechanism that is assured. Authentication mechanism assurance uses certificate policies that are mapped to security groups. The certificates that are issued from the policy grant users who use them to logon additional group memberships in their access token. The expected scenario for using this feature is that a user with a smart card or token device (e.g. USB token) logs on using a certificate (issued from a policy mapped to an administrator defined security group). With this addition group membership added to the access token of the user account a distinction can be made (through that group membership) that indicates the user logged on using a specific type of certificate. This allows resources on the network (and elsewhere) to be secured as normal (using group memberships in the access control list), but has the ability to effectively distinguish that the user logged on with a smart card, USB token, or some other type of certificate logon method. Since the administrator can map different types of certificates (using different certificate policies) to different group memberships, it is also possible to distinguish the type of certificate.
As an example, consider this scenario: Three certificate policies
Now assume that these policies are mapped to three different security groups:
Now consider there are three different types of smart cards (they could all be the same type of smart card). Imagine they are categorized differently as in they have different colors or stickers indicating the following):
Now resource administrators could secure resources in this way:
Such a configuration would allow users who logon with Confidential smart cards to access the resources secured for Confidential Users. The users who logon with Secret smart cards can access the resources shared to the Secret Users group. The users who logon with Top Secret smart cards can access the resources shared to the Top Secret Users group. The users who logon using a username and password will not be able to access any of the resources described above.
Therefore, the authentication mechanism assurance allows administrators to secure resources (including applications) such that only users who logged on with a certificate based mechanism are granted access. Further, whether the user is able to gain access to specific resources also depends on the type of certificate (indicated by the certificate template and policy) that the user presents during logon.
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