this article we propose a standard for role-based access control (RBAC). Although RBAC models have received broad support as a generalized approach to access control, and are well recognized for their many advantages in performing large-scale authorization management, no single authoritative definition of RBAC exists today. This lack of a widely accepted model results in uncertainty and confusion about RBAC's utility and meaning. The standard proposed here seeks to resolve this situation by unifying ideas from a base of frequently referenced RBAC models, commercial products, and research prototypes. It is intended to serve as a foundation for product development, evaluation, and procurement specification. Although RBAC continues to evolve as users, researchers, and vendors gain experience with its application, we feel the features and components proposed in this standard represent a fundamental and stable set of mechanisms that may be enhanced by developers in further meeting the needs of their customers. As such, this document does not attempt to standardize RBAC features beyond those that have achieved acceptance in the commercial marketplace and research community, but instead focuses on defining a fundamental and stable set of RBAC components. This standard is organized into the RBAC Reference Model and the RBAC System and Administrative Functional Specification. The reference model defines the scope of features that comprise the standard and provides a consistent vocabulary in support of the specification. The RBAC System and Administrative Functional Specification defines functional requirements for administrative operations and queries for the creation, maintenance, and review of RBAC sets and relations, as well as for specifying system level functionality in sup...

The Ponder language provides a common means of specifying security policies that map onto various access control implementation mechanisms for firewalls, operating systems, databases and Java. It supports obligation policies that are event triggered conditionaction rules for policy based management of networks and distributed systems. Ponder can also be used for security management activities such as registration of users or logging and auditing events for dealing with access to critical resources or security violations. Key concepts of the language include roles to group policies relating to a position in an organisation, relationships to define interactions between roles and management structures to define a configuration of roles and relationships pertaining to an organisational unit such as a department. These reusable composite policy specifications cater for the complexity of large enterprise information systems. Ponder is declarative, stronglytyped and object-oriented which makes the language flexible, extensible and adaptable to a wide range of management requirements.

We propose a new distributed security infrastructure, called SDSI (pronounced "Sudsy"). SDSI combines a simple public-key infrastructure design with a means of defining groups and issuing group-membership certificates. SDSI's groups provides simple, clear terminology for defining access-control lists and security policies. SDSI's design emphasizes linked local name spaces rather than a hierarchical global name space.

We introduce the RT framework, a family of Rolebased Trust-management languages for representing policies and credentials in distributed authorization. RT combines the strengths of role-based access control and trustmanagement systems and is especially suitable for attributebased access control. Using a few simple credential forms, RT provides localized authority over roles, delegation in role definition, linked roles, and parameterized roles. RT also introduces manifold roles, which can be used to express threshold and separation-of-duty policies, and delegation of role activations. We formally define the semantics of credentials in the RT framework by presenting a translation from credentials to Datalog rules. This translation also shows that this semantics is algorithmically tractable. 1

We address the problem of authorization in large-scale, open...

A major drawback of existing access control systems is that they have all been developed with a specific access control policy in mind. This means that all protection requirements (i.e., accesses to be allowed or denied) must be specified in terms of the policy enforced by the system. While this may be trivial for some requirements, specification of other requirements may become quite complex or even impossible. The reason for this is that a single policy simply cannot capture different protection requirements users may need to enforce on different data. In this paper we take a first step towards a model able to support different access control policies. We propose a logical language for the specification of authorizations on which such a model can be based. The language allows users to specify, together with the authorizations, the policy according to which access control decisions are to be made. Policies are expressed by means of rules which enforce derivation of authorizations, con...

Modern distributed systems contain a large number of objects, and must be capable of evolving, without shutting down the complete system, to cater for changing requirements. There is a need for distributed, automated management agents whose behavior also has to dynamically change to reflect the evolution of the system being managed. Policies are a means of specifying and influencing management behavior within a distributed system, without coding the behavior into the manager agents. Our approach is aimed at specifying implementable policies, although policies may be initially specified at the organizational level (c.f. goals) and then refined to implementable actions. We are concerned with two types of policies. Authorization policies specify what activities a manager is permitted or forbidden to do to a set of target objects and are similar to security accesscontrol policies. Obligation policies specify what activities a manager must or must not do to a set of target objects and essen...

We introduce a simple Role-based Trust-management language RT 0 and a set-theoretic semantics for it. We also introduce credential graphs as a searchable representation of credentials in RT 0 and prove that reachability in credential graphs is sound and complete with respect to the semantics of RT 0 . Based on credential graphs, we give goal-directed algorithms to do credential chain discovery in RT 0 , both when credential storage is centralized and when credential storage is distributed. A goal-directed algorithm begins with an access-control query and searches for credentials relevant to the query, while avoiding considering the potentially very large number of credentials that are unrelated to the access-control decision at hand. This approach provides better expected-case performance than bottom-up algorithms. We show how our algorithms can be applied to SDSI 2.0 (the "SDSI" part of SPKI/SDSI 2.0). Our goal

In role-based access control (RBAC) permissions are associated with roles, and users are made members of roles thereby acquiring the roles ’ permissions. The motivation behind RBAC is to simplify administration. An appealing possibility is to use RBAC itself to manage RBAC, to further provide administrative convenience, especially in decentralizing administrative authority, responsibility and chores. This paper describes the motivation, intuition and outline of a new model for RBAC administration called ARBAC97 (administrative RBAC ‘97). ARBAC97 has three components: URA97 (user-role assignment ‘97), PRA97 (permissionrole assignment ‘97) and RRA97 (role-role assignment ‘97). URA97 was recently defined by Sandhu and Bhamidipati [SB97]. ARBAC97 incorporates URA97, builds upon it to define PRA97 and some components of RRA97, and introduces additional concepts in developing RRA97.

Security remains a major roadblock to universal acceptance of the Web for many kinds of transactions, especially since the recent sharp increase in remotely exploitable vulnerabilities has been attributed to Web application bugs. Many verification tools are discovering previously unknown vulnerabilities in legacy C programs, raising hopes that the same success can be achieved with Web applications. In this paper, we describe a sound and holistic approach to ensuring Web application security. Viewing Web application vulnerabilities as a secure information flow problem, we created a lattice-based static analysis algorithm derived from type systems and typestate, and addressed its soundness. During the analysis, sections of code considered vulnerable are instrumented with runtime guards, thus securing Web applications in the absence of user intervention. With sufficient annotations, runtime overhead can be reduced to zero. We also created a tool named WebSSARI (Web application Security by Static Analysis and Runtime Inspection) to test our algorithm, and used it to verify 230 open-source Web application projects on SourceForge.net, which were selected to represent projects of different maturity, popularity, and scale. 69 contained vulnerabilities and their developers were notified. 38 projects acknowledged our findings and stated their plans to provide patches. Our statistics also show that static analysis reduced potential runtime overhead by 98.4%. Categories and Subject Descriptors D.2.4 [Software Engineering]: Software / Program Verification – class invariants, formal methods; D.4.6 [Operating Systems]: Security and Protection – information flow controls, correctness proofs, formal methods; K.6.5 [Computing Milieux]: Security and Protection – invasive software, unauthorized access.