Role-permission Assignments Research Articles

VeRA: Verifying RBAC and Authorization Constraints Models of Web Applications

The software security issue is being paid great attention from the software development community as security violations have emerged variously. Developers often use access control techniques to restrict some security breaches to software systems’ resources. The addition of authorization constraints to the role-based access control model increases the ability to express access rules in real-world problems. However, the complexity of combining components, libraries and programming languages during the implementation stage of web systems’ access control policies may arise potential flaws that make applications’ access control policies inconsistent with their specifications. In this paper, we introduce an approach to review the implementation of these models in web applications written by Java EE according to the MVC architecture under the support of the Spring Security framework. The approach can help developers in detecting flaws in the assignment implementation process of the models. First, the approach focuses on extracting the information about users and roles from the database of the web application. We then analyze policy configuration files to establish the access analysis tree of the application. Next, algorithms are introduced to validate the correctness of the implemented user-role and role-permission assignments in the application system. Lastly, we developed a tool called VeRA, to automatically support the verification process. The tool is also experimented with a number of access violation scenarios in the medical record management system.

A Policy Model and Framework for Context-Aware Access Control to Information Resources†

In today’s dynamic ICT environments, the ability to control users’ access to information resources and services has become ever important. On the one hand, it should provide flexibility to adapt to the users’ changing needs, while on the other hand, it should not be compromised. The user is often faced with different contexts and environments that may change the user’s information needs. To allow for this, it is essential to incorporate the dynamically changing context information into the access control policies to reflect different contexts and environments through the use of a new context-aware access control (CAAC) approach with both dynamic associations of user-role and role-permission capabilities. Our proposed CAAC framework differs from the existing access control frameworks in that it supports context-sensitive access control to information resources and dynamically re-evaluates the access control decisions when there are dynamic changes to the context. It uses the dynamic context information to specify the user-role and role-permission assignment policies. We first present a formal policy model for our framework, specifying CAAC policies. Using this model, we then introduce a policy ontology for modeling CAAC policies and a policy enforcement architecture which supports access to resources according to the dynamically changing context information. In addition, we demonstrate the feasibility of our framework by considering (i) the completeness, correctness and consistency of the ontology concepts through application to healthcare scenarios and (ii) the performance and usability testing of the framework when using desktop and mobile-based prototypes.

Supporting user authorization queries in RBAC systems by role–permission reassignment

The User Authorization Query (UAQ) Problem is a key issue related to efficient handling of users’ access requests in Role Based Access Control (RBAC) systems. However, there may not exist any solution to a given UAQ problem due to the limitation caused by the current system state, because missing any requested permission may thwart a task, while an extra permission may bring an intolerable risk to the system. Hence, update of the role–permission assignment is needed to support the feasibility of an UAQ problem. In this paper, we study fundamental problems related to role–permission reassignment, including the RVP problem the goal of which is to determine whether a given role–permission assignment satisfies all reassignment objectives and does not violate any prerequisite constraint or permission-capacity constraint, the RFP problem which verifies whether there exists a valid role–permission assignment, and the RGP problem which studies how to generate a valid role–permission assignment. We present the computational complexity analysis of RVP, RFP and RGP, showing that RVP is solvable in linear time, while both RFP and RGP are NP-hard. We also propose an approach for RGP, which incorporates a preprocessing to decrease the size of the problem, and reduce it to an SAT problem. Finally, experimental results show the validity and effectiveness of our proposed approach.

An Approach for Hierarchical RBAC Reconfiguration With Minimal Perturbation

In recent years, role-based access control (RBAC) has become the de facto access control model due to its good applicability and high flexibility. Since the organizations need to update the access control policies to meet the changes in employees, departments, business processes, and so on. The RBAC system has to define new roles and becomes more and more bloated because it's difficult to modify the role-permission assignment with no or minimal impact to other users and roles. Hence, there is a great need to reconfigure the RBAC system over time to reduce its structural complexity and keep as close as possible to the original. Several RBAC reconfiguration approaches have been proposed aiming at generating roles similar to the deployed ones, but they neglect the differences in deployed roles that some of them are useless for the system and generate more roles than needed, which in turn increases the system structure complexity. In this paper, we first propose three indicators to evaluate the quality of deployed roles and define the problem of hierarchy RBAC reconfiguration with minimal weight structure complexity and perturbation. Then, the hierarchy RBAC reconfiguration approach and its algorithm process are proposed to address the problem. To conclude, we demonstrate the effectiveness and stability of our approach through experiments.

A Role-Permission Assignment Method of RBAC Involved Conflicting Constraints under E-CARGO

Multi-agent systems are historically one of the most crucial problems and now become an important topic in cognitive theory. In the view of ontology theory, multi-agent systems are usually related to roles and agents are the executors of roles. We investigate an improved multi-agent system by solving the RBAC role-permission assignment problem with conflicting constrains in this paper, under the E-CARGO model that provides the formalization, the description of conflicts and the algorithms used in this paper. Simulation experiments with comprehensive consideration can verify the correctness of our method.

Meeting Cardinality Constraints in Role Mining

Role mining is a critical step for organizations that migrate from traditional access control mechanisms to role based access control (RBAC). Additional constraints may be imposed while generating roles from a given user-permission assignment relation. In this paper we consider two such constraints which are the dual of each other. A role-usage cardinality constraint limits the maximum number of roles any user can have. Its dual, the permission-distribution cardinality constraint, limits the maximum number of roles to which a permission can belong. These two constraints impose mutually contradictory requirements on user to role and role to permission assignments. An attempt to satisfy one of the constraints may result in a violation of the other. We show that the constrained role mining problem is NP-Complete and present heuristic solutions. Two distinct frameworks are presented in this paper. In the first approach, roles are initially mined without taking the constraints into account. The user-role and role-permission assignments are then checked for constraint violation in a post-processing step, and appropriately re-assigned, if necessary. In the second approach, constraints are enforced during the process of role mining. The methods are first applied on problems that consider the two constraints individually, and then with both considered together. Both methods are evaluated over a number of real-world data sets.

On the complexity of role updating feasibility problem in RBAC

In Role Based Access Control (RBAC) systems, it is necessary and important to update the role–permission assignments in order to reflect the evolutions of the system transactions. However, role updating is generally complex and challenging, especially for large-scale RBAC systems. This is because the resulting state is usually expected to meet various requirements and constraints. In this paper, we focus on a fundamental problem of role updating in RBAC, which determines whether there exists a valid role–permission assignment, i.e., whether it can satisfy all the requirements of the role updating and without violating any role–capacity or permission–capacity constraint. We formally define such a problem as the Role Updating Feasibility Problem (RUFP), and study the computational complexity of RUFP in different subcases. Our results show that although several subcases are solvable in linear time, this problem is NP-complete in the general case.

AMTRAC: An administrative model for temporal role-based access control

Over the years, Role Based Access Control (RBAC) has received significant attention in system security and administration. The Temporal Role Based Access Control (TRBAC) model is an extension of RBAC that allows one to specify periodic enabling and disabling of roles in a role enabling base (REB). While decentralized administration and delegation of administrative responsibilities in large RBAC systems is managed using an administrative role based access control model like ARBAC97, no administrative model for TRBAC has yet been proposed. In this paper, we introduce such a model and name it AMTRAC (Administrative Model for Temporal Role based Access Control). AMTRAC defines a broad range of relations that control user-role assignment, role-permission assignment, role–role assignment and role enabling base assignment. Since the first three are similar to those in ARBAC97, the role enabling base assignment component has been discussed in detail in this paper. The different ways by which role enabling conditions of regular roles can be modified are first explained. We then show how to specify which of the administrative roles are authorized to modify the role enabling conditions of any regular role. An exhaustive set of commands for authorization enforcement along with their pre and postconditions is also presented. Together, this would facilitate practical deployment and security analysis of TRBAC systems.

How to Find a Rigorous Set of Roles for Application of RBAC

Role-based access control (RBAC) has been adopted successfully by a variety of security system by reducing the complexity of the management of access control. The least privilege principle is a very important constraint policy of RBAC. Devising a complete and correct set of roles for supporting the least privilege principle has been recognized as one of the most important tasks in implementing RBAC. A key problem is how to find such sets of roles which have the least permissions. In fact, when the number of role-permission assignments is large, it is almost impossible to find a rigorous set of roles which has the completely same set of permissions required by a user. To address this problem, we research the problem how to find such the rigorous combinations obeying the principle of least permissions. By bringing forward the concept of the l east privilege mining problem, we describe the methods to resolve the problem and some instances of its applications, too. Moreover, the corresponding algorithms are displayed. Specially, by analyzing the complexity of least privilege mining problem, the method based on evolutionary algorithm is shown appreciate. Correspondingly, the experiments are accomplished to prove our opinions. Finally, the paper is concluded and some future work is posed.

Formal foundations for hybrid hierarchies in GTRBAC

A role hierarchy defines permission acquisition and role-activation semantics through role--role relationships. It can be utilized for efficiently and effectively structuring functional roles of an organization having related access-control needs. The focus of this paper is the analysis of hybrid role hierarchies in the context of the generalized temporal role-based access control (GTRBAC) model that allows specification of a comprehensive set of temporal constraints on role, user-role, and role-permission assignments. We introduce the notion of uniquely activable set (UAS) associated with a role hierarchy that indicates the access capabilities of a user resulting from his membership to a role in the hierarchy. Identifying such a role set is essential, while making an authorization decision about whether or not a user should be allowed to activate a particular combination of roles in a single session. We formally show how UAS can be determined for a hybrid hierarchy. Furthermore, within a hybrid hierarchy, various hierarchical relations may be derived between an arbitrary pair of roles. We present a set of inference rules that can be used to generate all the possible derived relations that can be inferred from a specified set of hierarchical relations and show that it is sound and complete . We also present an analysis of hierarchy transformations with respect to role addition, deletion, and partitioning, and show how various cases of these transformations allow the original permission acquisition and role-activation semantics to be managed. The formal results presented here provide a basis for developing efficient security administration and management tools.

An RBAC-Based Access Control Model for Object-Oriented Systems Offering Dynamic Aspect Features

This paper proposes a model for access control within object-oriented systems. The model is based on RBAC (role-based access control) and is called DRBAC (dynamic RBAC). Although RBAC is powerful in access control, the original design of RBAC required that user-role assignments and role-permission assignments should be handled statically (i.e., the assignments should be handled by human beings). Nevertheless, the following dynamic features are necessary in access control within a software system: (a) managing dynamic role switching, (b) avoiding Trojan horses, (c) managing role associations, and (d) handling dynamic role creation and deletion. DRBAC offers the dynamic features. This paper proposes DRBAC.

A generalized temporal role-based access control model

Role-based access control (RBAC) models have generated a great interest in the security community as a powerful and generalized approach to security management. In many practical scenarios, users may be restricted to assume roles only at predefined time periods. Furthermore, roles may only be invoked on prespecified intervals of time depending upon when certain actions are permitted. To capture such dynamic aspects of a role, a temporal RBAC (TRBAC) model has been recently proposed. However, the TRBAC model addresses the role enabling constraints only. In This work, we propose a generalized temporal role-based access control (GTRBAC) model capable of expressing a wider range of temporal constraints. In particular, the model allows expressing periodic as well as duration constraints on roles, user-role assignments, and role-permission assignments. In an interval, activation of a role can further be restricted as a result of numerous activation constraints including cardinality constraints and maximum active duration constraints. The GTRBAC model extends the syntactic structure of the TRBAC model and its event and trigger expressions subsume those of TRBAC. Furthermore, GTRBAC allows expressing role hierarchies and separation of duty (SoD) constraints for specifying fine-grained temporal semantics.