Claim-Based Access Control (CBAC) Model

Conditional ACEs or expressions were introduced to the authorization system to enable its access control decisions to be not only based on the identity of the trustees, but also based on whether trustees met the particular conditions. A user access request can be granted or denied by comparing the ACLs on the security descriptor with the attributes, called claims, of the user access token. For more details on the conditional ACEs, see [MS-DTYP] section

A claim is an attribute that makes an assertion about an entity with which it is associated. Claims are broadly classified in three categories based on entity: user claims, device claims, and resource properties or claims.

User claim: A claim that is associated with an authenticated user account. Examples of user claims are employer of the user, type of the employment, role in organization, and organizational division of the user.

Device claim: A claim that is associated with an authenticated computer account. Along with the claims, it can be included in the user token of the user who is trying to access the resource. Examples of device claims are the IT management status of the computer and the department in which the computer is designated to operate.

Resource property: A property that is associated with the resource on the system. Examples of resource properties are classification of the resource such as High-Business-Impact, Confidential, and Personally-Identifiable-Information.

CBAC is an access control paradigm that uses the claims to make access-control decisions to resources. In Windows, CBAC is built on the conditional ACEs feature, not only to use the user claims, but also to use the resource claims, which are referred to as resource properties, in order to make access control decisions. If the resource also has a resource claim "Division" that is equal to Sales, the policy condition can be stated using the SDDL syntax.

"O:BAG:BAD:(XA; ;FX;;;S-1-1-0;(@User. Division==@Resource. Division))"

Using this approach, the "Division" claim of the resource can be separately defined and changed without having to update the conditional expression on the resource.