Specification Of Access Control Policies Research Articles

Specification and adaptive verification of access control policy for cyber-physical-social spaces

Cyber-Physical-Social Space (CPSS) is a promising paradigm to provide people with an intelligent environment by emphasizing the deep fusion of cyberspace, physical space, and social space. The interdependence of these spaces makes that CPSS is more likely to be attacked. The attack consequences may directly affect the state of the physical world and even endanger the people’s life. Thus, the most challenging issue for CPSS is to ensure the space security. However, existing security analysis methods focus on the static analysis at the design phase. They do not consider the open and dynamic characteristics which are the core features of CPSS. In this paper, we propose an adaptive security analysis framework for CPSS to prevent the unauthorized flow of information. Firstly, the access control model of CPSS is proposed. It controls the access behaviors by considering the space information covering the social, cyber, and physical spaces. Secondly, Labelled Transition System (LTS) is established to describe the future evolutions of CPSS. The space states in the LTS which violate the security requirements are reasoned by the model checking technology. Thirdly, a policy adjustment method is proposed to prevent the system from entering the violated states or mitigate the bad results caused by the violations. In the end, the effectiveness of our approach is evaluated by a smart building case, and the necessity of our approach is analyzed by the performance evaluation.

A Rigorous Framework for Specification, Analysis and Enforcement of Access Control Policies

Access control systems are widely used means for the protection of computing systems. They are defined in terms of access control policies regulating the access to system resources. In this paper, we introduce a formally-defined, fully-implemented framework for specification, analysis and enforcement of attribute-based access control policies. The framework rests on FACPL, a language with a compact, yet expressive, syntax for specification of real-world access control policies and with a rigorously defined denotational semantics. The framework enables the automated verification of properties regarding both the authorisations enforced by single policies and the relationships among multiple policies. Effectiveness and performance of the analysis rely on a semantic-preserving representation of FACPL policies in terms of SMT formulae and on the use of efficient SMT solvers. Our analysis approach explicitly addresses some crucial aspects of policy evaluation, such as missing attributes, erroneous values and obligations, which are instead overlooked in other proposals. The framework is supported by Java-based tools, among which an Eclipse-based IDE offering a tailored development and analysis environment for FACPL policies and a Java library for policy enforcement. We illustrate the framework and its formal ingredients by means of an e-Health case study, while its effectiveness is assessed by means of performance stress tests and experiments on a well-established benchmark.

Formal analysis of XACML policies using SMT

The eXtensible Access Control Markup Language (XACML) has attracted significant attention from both industry and academia, and has become the de facto standard for the specification of access control policies. However, its XML-based verbose syntax and rich set of constructs make the authoring of XACML policies difficult and error-prone. Several automated tools have been proposed to analyze XACML policies before their actual deployment. However, most of the existing tools either cannot efficiently reason about non-Boolean attributes, which often appear in XACML policies, or restrict the analysis to a small set of properties. This work presents a policy analysis framework for the verification of XACML policies based on SAT modulo theories (SMT). We show how XACML policies can be encoded into SMT formulas, along with a query language able to express a variety of well-known security properties, for policy analysis. By being able to reason over non-Boolean attributes, our SMT-based policy analysis framework allows a fine-grained policy analysis while relieving policy authors of the burden of defining an appropriate level of granularity of the analysis. An evaluation of the framework shows that it is computationally efficient and requires less memory compared to existing approaches.

Semiautomated Verification of Access Control Implementation in Industrial Networked Systems

Access control is a necessary building block in the security of any kind of cyber system and, in this sense, industrial networked systems (INSs) make no exception. Typically, access control policies are specified at a high implementation-independent level of abstraction and then mapped onto the real system by leveraging available policy enforcement mechanisms. Unfortunately, different from general-purpose ICT systems, enforcement mechanisms are generally very basic in INS. As a consequence, verifying the correctness of policy implementation becomes a crucial task, especially cumbersome when it needs to be carried out entirely by hand. This paper presents a new methodology, which also serves as the basis of a purposely developed software tool conceived to cope with the lack of policy enforcement mechanisms in INS and to allow semiautomatic verification of policy implementation. Our approach is based on a twofold system model that enables both the abstract specification of access control policies and the detailed description of the target physical system. These two separate views are then combined to automatically determine whether the current system implementation matches the policy specification.

A twofold model for the analysis of access control policies in industrial networked systems

Requirements concerning the specification and correct implementation of access control policies have become more and more popular in industrial networked systems during the last years. Unfortunately, the peculiar characteristics of industrial systems often prevent the designer from taking full advantage of technologies and techniques already developed and profitably employed in other application areas. In particular, the unavailability and/or impossibility of adopting hardware (h/w) and software (s/w) mechanisms able to automatically enforce the policies defined at a high level of abstraction, often results in checking the correctness of policy implementation in the real system manually. The first step towards carrying out this cumbersome task in an automated way is the development of a model able to capture both the high level policy specification as well as the details and low-level mechanisms characterizing the actual system implementation. This paper introduces a twofold model for the description of access control policies in industrial environments aimed at coping with this requirement and which can be profitably adopted in several kinds of automated analysis.

A Tool Supporting End-User Development of Access Control in Web Applications

End-user development (EUD) is drawing an increasing attention due to the necessity of users to frequently extend and personalize their applications. In particular, EUD in the context of Web (EUDWeb) is focusing on technologies capable of supporting development tasks that the end-user feels more complex. However, although the specification and implementation of access control is perceived as a particularly complex task, little efforts have been made to support it within current EUDWeb environments. Thus, in this paper we propose an EUDWeb framework and tool for the specification and the generation of web applications embedding access control mechanisms. We extended a previous mockup-based EUDWeb approach, by introducing visual assistance mechanisms enabling the specification of role-based access control policies, and their integration within the application logic. The usability of the proposed framework has been evaluated by means of a user study, in which we have shown that a group of heterogeneous end-users could proficiently use the proposed framework to develop meaningful web applications, some of which including access control functionalities.

A metamodel of access control for distributed environments: Applications and properties

We describe a metamodel for access control, designed to take into account the specific requirements of distributed environments. We see a distributed system consisting of several sites, each with its own resources to protect, as a federation, and propose a framework for the specification (and enforcement) of global access control policies that take into account the local policies specified by each member of the federation. The framework provides mechanisms to specify heterogeneous local access control policies, to define policy composition operators, and to use them to define conflict-free access authorisation decisions. We use a declarative formalism in order to give an operational semantics to the distributed metamodel. We then show how properties of policies can be directly obtained from standard results for the operational semantics of access request evaluation.

A framework for privacy aware data management in relational databases

This paper is about MAPaS – modelling and analysis of privacy-aware systems – framework, which targets the development of privacy aware SQL queries operating on a given database. MAPaS supports the specification of purpose and role-based access control policies that regulate the access to data based on purpose compliance, role and purpose-based authorisations. The current version of MAPaS allows the definition of the scheme of the database whose data must be protected and the SQL queries that should be executed on such a database. A rich analysis toolkit allows user to assess the compliance of these queries with the specified privacy policies. The analysis can be done even before the database is populated. The use of MAPaS bring users to define SQL queries which are privacy aware by design.

Dynamic Access Control Policies: Specification and Verification

Security requirements deal with the protection of assets against unauthorized access (disclosure or modification) and their availability to authorized users. Temporal constraints of history-based access control policies are difficult to express naturally in traditional policy languages. We propose a compositional formal framework for the specification and verification of temporal access control policies for security critical systems in which history-based policies and other temporal constraints can be expressed. In particular, our framework allows for the specification of policies that can change dynamically in response to time or events enabling dynamic reconfiguration of the access control mechanisms. The framework utilizes a single well-defined formalism, interval temporal logic, for defining the semantics of these policies and to reason about them. We illustrate our approach with a detailed case study of an electronic paper submission system showing the compositional verification of their safety, liveness and information flow properties.

Empowering citizens with access control mechanisms to their personal health resources

BackgroundAdvancements in information and communication technologies have allowed the development of new approaches to the management and use of healthcare resources. Nowadays it is possible to address complex issues such as meaningful access to distributed data or communication and understanding among heterogeneous systems. As a consequence, the discussion focuses on the administration of the whole set of resources providing knowledge about a single subject of care (SoC). New trends make the SoC administrator and responsible for all these elements (related to his/her demographic data, health, well-being, social conditions, etc.) and s/he is granted the ability of controlling access to them by third parties. The subject of care exchanges his/her passive role without any decision capacity for an active one allowing to control who accesses what. PurposeWe study the necessary access control infrastructure to support this approach and develop mechanisms based on semantic tools to assist the subject of care with the specification of access control policies. This infrastructure is a building block of a wider scenario, the Person-Oriented Virtual Organization (POVO), aiming at integrating all the resources related to each citizen's health-related data. The POVO covers the wide range and heterogeneity of available healthcare resources (e.g., information sources, monitoring devices, or software simulation tools) and grants each SoC the access control to them. MethodsSeveral methodological issues are crucial for the design of the targeted infrastructure. The distributed system concept and focus are reviewed from the service oriented architecture (SOA) perspective. The main frameworks for the formalization of distributed system architectures (Reference Model-Open Distributed Processing, RM-ODP; and Model Driven Architecture, MDA) are introduced, as well as how the use of the Unified Modelling Language (UML) is standardized. The specification of access control policies and decision making mechanisms are essential keys for this approach and they are accomplished by using semantic technologies (i.e., ontologies, rule languages, and inference engines). ResultsThe results are mainly focused on the security and access control of the proposed scenario. An ontology has been designed and developed for the POVO covering the terminology of the scenario and easing the automation of administration tasks. Over that ontology, an access control mechanism based on rule languages allows specifying access control policies, and an inference engine performs the decision making process automatically. The usability of solutions to ease administration tasks to the SoC is improved by the Me-As-An-Admin (M3A) application. This guides the SoC through the specification of personal access control policies to his/her distributed resources by using semantic technologies (e.g., metamodeling, model-to-text transformations, etc.). All results are developed as services and included in an architecture in accordance with standards and principles of openness and interoperability. ConclusionsCurrent technology can bring health, social and well-being care actually centered on citizens, and granting each person the management of his/her health information. However, the application of technology without adopting methodologies or normalized guidelines will reduce the interoperability of solutions developed, failing in the development of advanced services and improved scenarios for health delivery. Standards and reference architectures can be cornerstones for future-proof and powerful developments. Finally, not only technology must follow citizen-centric approaches, but also the gaps needing legislative efforts that support these new paradigms of healthcare delivery must be identified and addressed.

Design and Evaluation of XACML Conflict Policies Detection Mechanism

The evolution of distributed computing technologies like grid computing, peer-to-peer computing, pervasive computing, ubiquitous computing, autonomic computing, cloud computing etc. has led to the development of complex virtual systems. These systems enable sharing of resources and services distributed over geographically dispersed, heterogeneous, autonomous administrative domains and allow one to efficiently perform a compute or storage intensive task by harnessing the features available over other domains. The resources and services provided by service providers are generally protected by complex access control policies. These access control policies are expressed using policy specification languages. One of the popular, exhaustive and feature rich access control policy specification language is XACML, which is an OASIS standard also. The XACML policies are specified either manually or using automated XACML policy specification tools. Among major problems that policy administrators face is the problem of conflict policies. Conflict policies can have serious consequences and may lead to unauthorized access. This paper presents the design, implementation and evaluation of a conflict policy detection mechanism that can be used by policy administrators to proactively detect conflict XACML policies present in a policy database. This saves administrators and initiators of job from unnecessary problems arising due to presence of conflicts. The mechanism presented is simple, scalable, efficient and can be used to detect policies conflicting with respect to subject, resource, and action attributes. The mechanism has been evaluated by simulating a distributed policy based authorization and XACML access control system. A number of conflict policies of different nature have been injected in the policy database and conflicts have been identified through proposed XACML conflict policy detection algorithm. The implementation results show that the mechanism efficiently detects conflict policies having conflicts with respect to subject, resource and action attributes. This demonstrates that the approach is workable and can be used to detect conflict policies among a set of XACML policies.

Security analysis of GTRBAC and its variants using model checking

Security analysis is a formal verification technique to ascertain certain desirable guarantees on the access control policy specification. Given a set of access control policies, a general safety requirement in such a system is to determine whether a desirable property is satisfied in all the reachable states. Such an analysis calls for the use of formal verification techniques. While formal analysis on traditional Role Based Access Control (RBAC) has been done to some extent, recent extensions to RBAC lack such an analysis. In this paper, we consider the temporal RBAC extensions and propose a formal technique using timed automata to perform security analysis by analyzing both safety and liveness properties. Using safety properties one ensures that something bad never happens while liveness properties show that some good state is also achieved. GTRBAC is a well accepted generalized temporal RBAC model which can handle a wide range of temporal constraints while specifying different access control policies. Analysis of such a model involves a process of mapping a GTRBAC based system into a state transition system. Different reduction rules are proposed to simplify the modeling process depending upon the constraints supported by the system. The effect of different constraints on the modeling process is also studied.

A fine-grained access control model for relational databases

Fine-grained access control (FGAC) must be supported by relational databases to satisfy the requirements of privacy preserving and Internet-based applications. Though much work on FGAC models has been conducted, there are still a number of ongoing problems. We propose a new FGAC model which supports the specification of open access control policies as well as closed access control policies in relational databases. The negative authorization is supported, which allows the security administrator to specify what data should not be accessed by certain users. Moreover, multiple policies defined to regulate user access together are also supported. The definition and combination algorithm of multiple policies are thus provided. Finally, we implement the proposed FGAC model as a component of the database management system (DBMS) and evaluate its performance. The performance results show that the proposed model is feasible.

Sharing and hiding online secrets

PurposeThis paper aims to manage access control tasks to satisfy the user privacy needs of online information resources according to social relations and tags.Design/methodology/approachThe study proposes a method for access control management in the online social context. The proposed method includes the access control policy management process, metadata of access control policies, the data of ontologies, tags, and social relations, and conflict detection rules.FindingsOnline information sharing and hiding, which needs to consider social relations and mentioned topics, is a unique context and needs a novel access control mechanism. Ontologies are powerful and expressive enough to identify conflicts in access control policies. The paper provides a method using ontologies to control the access control activities based on social relations and tags on web content. The effectiveness of the method's conflict detection rules is validated through several scenarios.Research limitations/implicationsTo make the proposed method suitable for widespread usage, further work is required to develop an access control policy specification and conflict detection tool. The proposed method introduces relatively novel usage scenarios, which consider social relationships, and tags compared with existing access control methods for online information sharing.Practical implicationsThe proposed access control mechanism can be integrated into existing web sites. Online users can use this method to share information more easily than at present.Originality/valueThe method enables flexible access control in social contexts and handles unavoidable conflicts. It also opens the way to new access control scenarios in online social activities. The method can be used to keep secrets hidden from selected people.

The Policy Machine: A novel architecture and framework for access control policy specification and enforcement

The ability to control access to sensitive data in accordance with policy is perhaps the most fundamental security requirement. Despite over four decades of security research, the limited ability for existing access control mechanisms to generically enforce policy persists. While researchers, practitioners and policy makers have specified a large variety of access control policies to address real-world security issues, only a relatively small subset of these policies can be enforced through off-the-shelf technology, and even a smaller subset can be enforced by any one mechanism. In this paper, we propose an access control framework, referred to as the Policy Machine (PM) that fundamentally changes the way policy is expressed and enforced. Employing PM helps in building high assurance enforcement mechanisms in three respects. First, only a relatively small piece of the overall access control mechanism needs to be included in the host system (e.g., an operating system or application). This significantly reduces the amount of code that needs to be trusted. Second, it is possible to enforce the precise policies of resource owners, without compromise on enforcement or resorting to less effective administrative procedures. Third, the PM is capable of generically imposing confinement constraints that can be used to prevent leakage of information to unauthorized principals within the context of a variety of policies to include the commonly implemented Discretionary Access Control and Role-Based Access Control models.

A type system for Discretionary Access Control

Discretionary Access Control (DAC) systems provide powerful resource management mechanisms based on the selective distribution of capabilities to selected classes of principals. We study a type-based theory of DAC models for a process calculus that extends Cardelli, Ghelli and Gordon's pi-calculus with groups (Cardelliet al. 2005). In our theory, groups play the role of principals and form the unit of abstraction for our access control policies, and types allow the specification of fine-grained access control policies to govern the transmission of names, bound the (iterated) re-transmission of capabilities and predicate their use on the inability to pass them to third parties. The type system relies on subtyping to achieve a selective distribution of capabilities to the groups that control the communication channels. We show that the typing and subtyping relationships of the calculus are decidable. We also prove a type safety result, showing that in well-typed processes all names:(i)flow according to the access control policies specified by their types; and(ii)are received at the intended sites with the intended capabilities.We illustrate the expressive power and the flexibility of the typing system using several examples.

A Meta-model of Access Control in a Fibred Security Language

The issue of representing access control requirements continues to demand significant attention. The focus of researchers has traditionally been on developing particular access control models and policy specification languages for particular applications. However, this approach has resulted in an unnecessary surfeit of models and languages. In contrast, we describe a general access control model and a logic-based specification language from which both existing and novel access control models may be derived as particular cases and from which several approaches can be developed for domain-specific applications. We will argue that our general framework has a number of specific attractions and an implication of our work is to encourage a methodological shift from a study of the particulars of access control to its generalities.

Role-based access control for a Grid system using OGSA-DAI and Shibboleth

In this paper, we propose a new role-based access control (RBAC) system for Grid data resources in the Open Grid Services Architecture Data Access and Integration (OGSA-DAI). OGSA-DAI is a widely used framework for integrating data resources in Grids. However, OGSA-DAI's identity-based access control causes substantial administration overhead for the resource providers in virtual organizations (VOs) because of the direct mapping between individual Grid users and the privileges on the resources. To solve this problem, we used the Shibboleth, an attribute authorization service, to support RBAC within the OGSA-DAI. In addition, access control policies need to be specified and managed across multiple VOs. For the specification of access control policies, we used the Core and Hierarchical RBAC profile of the eXtensible Access Control Markup Language (XACML); and for distributed administration of those policies and the user-role assignments, we used the Object, Metadata and Artifacts Registry (OMAR). OMAR is based on the e-business eXtensible Markup Language (ebXML) registry specifications developed to achieve interoperable registries and repositories. Our RBAC system provides scalable and fine-grain access control and allows privacy protection. It also supports dynamic delegation of rights and user-role assignments, and reduces the administration overheads for the resource providers because they need to maintain only the mapping information from VO roles to local database roles. Moreover, unnecessary mapping and connections can be avoided by denying invalid requests at the VO level. Performance analysis shows that our RBAC system adds only a small overhead to the existing security infrastructure of OGSA-DAI.

Role-Based Access Control in a Data Grid Using the Storage Resource Broker and Shibboleth

In this paper, we propose a role-based access control (RBAC) system for data resources in the Storage Resource Broker (SRB). The SRB is a Data Grid management system, which can integrate heterogeneous data resources of virtual organizations (VOs). The SRB stores the access control information of individual users in the Metadata Catalog (MCAT) database. However, because of the specific MCAT schema structure, this information can only be used by the SRB applications. If VOs also have many non-SRB applications, each with its own storage format for user access control information, it creates a scalability problem with regard to administration. To solve this problem, we developed a RBAC system with Shibboleth, which is an attribute authorization service currently being used in many Grid environments. Thus, the administration overhead is reduced because the role privileges of individual users are now managed by Shibboleth, not by MCAT or applications. In addition, access control policies need to be specified and managed across multiple VOs. For the specification of access control policies, we used the Core and Hierarchical RBAC profile of the eXtensible Access Control Markup Language (XACML); and for distributed administration of those policies, we used the Object, Metadata and Artifacts Registry (OMAR). OMAR is based on the e-business eXtensible Markup Language (ebXML) registry specifications developed to achieve interoperable registries and repositories. Our RBAC system provides scalable and fine-grain access control and allows privacy protection. Performance analysis shows that our system adds only a small overhead to the existing security infrastructure of the SRB.

Rewrite Based Specification of Access Control Policies

Data protection within information systems is one of the main concerns in computer systems security and different access control policies can be used to specify the access requests that should be granted or denied. These access control mechanisms should guarantee that information can be accessed only by authorized users and thus prevent all information leakage. We propose a methodology for specifying and implementing access control policies using the rewrite based framework Tom . This approach allows us to check that any reachable state obtained following a granted access in the implementation satisfies the policy specification. We show that when security levels are not totally ordered some information leakage can be detected.