Policy analysis for self-administrated role-based access control

Current techniques for security analysis of administrative role-based access control (ARBAC) policies restrict themselves to the separate administration assumption that essentially separates administrative roles from regular ones. The naive algorithm of tracking all users is all that is known for the security analysis of ARBAC policies without separate administration, and the state space explosion that this results in precludes building effective tools. In contrast, the separate administration assumption greatly simplifies the analysis since it makes it sufficient to track only one user at a time. However, separation limits the expressiveness of the models and restricts modeling distributed administrative control. In this paper, we undertake a fundamental study of analysis of ARBAC policies without the separate administration restriction, and show that analysis algorithms can be built that track only a bounded number of users, where the bound depends only on the number of administrative roles in the system. Using this fundamental insight paves the way for us to design an involved heuristic to further tame the state space explosion in practical systems. Our results are also very effective when applied on policies designed under the separate administration restriction. We implement our techniques and report on experiments conducted on several realistic case studies

Role Explosion: Acknowledging the Problem

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Authorization algorithms for permission-role assignments

Permission-role assignments (PRA) is one important process in Role-based access control (RBAC) which has been proven to be a flexible and useful access model for information sharing in distributed collaborative environments. However, problems may arise during the procedures of PRA. Conflicting permissions may assign to one role, and as a result, the role with the permissions can derive unexpected access capabilities. This paper aims to analyze the problems during the procedures of permission-role assignments in distributed collaborative environments and to develop authorization allocation algorithms to address the problems within permission-role assignments. The algorithms are extended to the case of PRA with the mobility of permission-role relationship. Finally, comparisons with other related work are discussed to demonstrate the effective work of the paper

Security Analysis of Role-based Access Control through Program Verification

We propose a novel scheme for proving administrative role-based access control (ARBAC) policies correct with respect to security properties using the powerful abstraction based tools available for program verification. Our scheme uses a combination of abstraction and reduction to program verification to perform security analysis. We convert ARBAC policies to imperative programs that simulate the policy abstractly, and then utilize further abstract-interpretation techniques from program analysis to analyze the programs in order to prove the policies secure. We argue that the aggressive set-abstractions and numerical-abstractions we use are natural and appropriate in the access control setting. We implement our scheme using a tool called VAC that translates ARBAC policies to imperative programs followed by an interval-based static analysis of the program, and show that we can effectively prove access control policies correct. The salient feature of our approach are the abstraction schemes we develop and the reduction of role-based access control security (which has nothing to do with programs) to program verification problems

AUTOMATING PERIODIC ROLE-CHECKS A TOOL-BASED APPROACH

The use of roles in Identity Management has proven to be a solution for reorganising and securing the access structures of organisations. One critical challenge companies face after they implemented roles is the maintenance of the role system itself. This includes sophisticated duties like periodically verifying the valid roles. We argue that due to the high complexity, periodic rolechecks need to be automated. However, as a result of lacking theoretical foundation, no approaches to leverage the level automation have been published so far. In this work we develop a catalogue of use cases that affect the role definitions within an organisation. We propose checkROLE, a tool for automated role-checking on basis of the defined use case catalogue

An Access Control and Trust Management Framework for Loosely-Coupled Multidomain Environment

Multidomain environments where multiple organizations interoperate with each other are becoming a reality as can be seen in emerging Internet-based enterprise applications. Access control to ensure secure interoperation in such an environment is a crucial challenge. A multidomain environment can be categorized as tightly-coupled and loosely-coupled. The access control challenges in the loosely-coupled environment have not been studied adequately in the literature. In a loosely-coupled environment, different domains do not know each other before they interoperate. Therefore, traditional approaches based on users' identities cannot be applied directly. Motivated by this, researchers have developed several attribute-based authorization approaches to dynamically build trust between previously unknown domains. However, these approaches all focus on building trust between individual requesting users and the resource providing domain. We demonstrate that such approaches are inefficient when the requests are issued by a set of users assigned to a functional role in the organization. Moreover, preserving principle of security has long been recognized as a challenging problem when facilitating interoperations. Existing research work has mainly focused on solving this problem only in a tightly-coupled environment where a global policy is used to preserve the principle of security. In this thesis, we propose a role-based access control and trust management framework for loosely-coupled environments. In particular, we allow the users to specify the interoperation requests in terms of requested permissions and propose several role mapping algorithms to map the requested permissions into roles in the resource providing domain. Then, we propose a Simplify algorithm to simplify the distributed proof procedures when a set of requests are issued according to the functions of some roles in the requesting domain. Our experiments show that our Simplify algorithm significantly simplifies such procedures when the total number of credentials in the environment is sufficiently large, which is quite common in practical applications. Finally, we propose a novel policy integration approach using the special semantics of hybrid role hierarchy to preserve the principle of security. At the end of this dissertation a brief discussion of implemented prototype of our framework is present