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ABAC enforces centralized management of authorization policies.
ABAC makes it easy to specify access rules as simple queries.
ABAC rules can be extraordinarily fine-grained and contextual.
ABAC rules can evaluate attributes of Subjects and Resources that are not inventoried by the authorization system.
ABAC rules need less maintenance and overhead because they do not require the creation or maintenance of the structure on which an RBAC model depends, e.g., roles and resource locations.
Figure 2 , below, shows an example of an actual ABAC policy implemented in an EmpowerID demonstration. Here, our application is asking if Alice can View Bob’s X-Ray. Our ABAC decision engine will base its decision on an elaborate ABAC policy (labeled Policies in the figure). The first policy check, Rule1, is that the action being taken is ‘View.’ The next extended requirement for Rule1 is that the company is not in ‘Emergency Mode,’i.e., in the middle of a crisis. However, to further extend the rule flexibility during a crisis, some roles may be granted additional permissions to enable those who would typically not be permitted to perform those activities to assist. The next check is only to allow ‘View ‘if the person is currently on the ‘Local Network.’ (Some sensitive activities might not be allowed if the person is outside the corporate network.) The next check confirms that the user performed a Multi-Factor Authentication (‘MFA’) with a Level of Assurance (‘LOA’) of at least ‘2’. This type of authentication refers to a stronger authentication method, like a physical token or mobile push. The policy also checks to see if the user is a member of the Doctors role and that their status is not currently set to out of office. Finally, the checks ensure that the X-Ray has neither been flagged as ‘Confidential’ nor the Subject has a relationship of the type Attending Physician.
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