How to securely break into RBAC: the BTG-RBAC model

Access control models describe frameworks that dictate how subjects (e.g. users) access resources. In the Role-Based Access Control (RBAC) model access to resources is based on the role the user holds within the organization. Although flexible and easier to manage within large-scale authorization frameworks, RBAC is usually a static model where access control decisions have only two output options: Grant or Deny. Break The Glass (BTG) policies can be provided in order to break or override the access controls within an access control policy but in a controlled and justifiable manner. The main objective of this paper is to integrate BTG within the NIST/ANSI RBAC model in a transparent and secure way so that it can be adopted generically in any domain where unanticipated or emergency situations may occur. The new proposed model, called BTG-RBAC, provides a third decision option BTG. This allows break the glass policies to be implemented in any application without any major changes to either the application or the RBAC authorization infrastructure, apart from the decision engine. Finally, in order to validate the model, we discuss how the BTG-RBAC model is being introduced within a Portuguese healthcare institution where the legislation requires that genetic information must be accessed by a restricted group of healthcare professionals. These professionals, advised by the ethical committee, have required and asked for the implementation of the BTG concept in order to comply with the said legislation.