Privilege States Based Access Control for Fine-Grained Intrusion Response

We propose an access control model specifically developed to support fine-grained response actions, such as request suspension and request tainting, in the context of an anomaly detection system for databases. To achieve such response semantics, the model introduces the concept of privilege states and orientation modes in the context of a role-based access control system. The central idea in our model is that privileges, assigned to a user or role, have a state attached to them, thereby resulting in a privilege states based access control (PSAC) system. In this paper, we present the design details and a formal model of PSAC tailored to database management systems (DBMSs). PSAC has been designed to also take into account role hierarchies that are often present in the access control models of current DBMSs. We have implemented PSAC in the PostgreSQL DBMS and in the paper, we discuss relevant implementation issues. We also report experimental results concerning the overhead of the access control enforcement in PSAC. Such results confirm that our design and algorithms are very efficient.