Context-Aware Access Control Using Semantic Policies

2009

The successful deployment of a security policy is closely related not only to the complexity of the security requirements but also to the capabilities/functionalities of the security devices. The complexity of the security requirements is additionally increased when contextual constraints are taken into account. Such situations appear when addressing the dynamism of some security requirements or when searching a finer granularity for the security rules. The context denotes those specific conditions in which the security requirements are to be met. (Re)deploying a contextual security policy depends on the security device functionalities: either (1) the devices include all functionalities necessary to deal with a context and the policy is consequently deployed for ensuring its automatic changes or (2) the devices do not have the right functionalities to entirely interpret a contextual requirement. We present a solution to cope with this issue: the (re)deployment of access control policies in a system that lacks the necessary functionalities to deal with contexts.

z.cliffe.schreuders.org

This paper presents a new policy language, known as functionality-based application confinement policy language (FBAC-PL). FBAC-PL takes a unique approach to expressing application-oriented access control policies. Policies for restricting applications are defined in terms of the features applications provide, by means of parameterised and hierarchical policy abstractions known as functionalities. Policies also include metadata for management and the automation of policy specification. The result is a novel scheme for application confinement policy that reuses, encapsulates and abstracts policy details, and facilitates a priori policy specification: that is, without having to rely solely on learning modes for creating policies to restrict applications. This paper presents the policy language, and illustrates its use with examples. A Linux-based implementation, which uses FBAC-PL, has demonstrated that this approach can overcome policy complexity and usability issues of previous schemes.

IFIP International Federation for Information Processing, 2004

Semantic-Web style metadata for advanced context representation and domain knowledge are likely to play a more and more important role within access control models and languages. This paper outlines how context metadata can be referred to in semantics-aware access control policies and discusses the main open issues in designing, producing, and maintaining metadata for security.

Mobile Networks and Applications, 2010

Controlling access in pervasive environments is crucial and a significant challenge because users and devices can connect from anywhere which results in users and resources becoming available at any point of time and location depending on the situation. Access control policies for this type of environment are required to conform to high-level business notions. In pervasive environments, these high-level notions refer to contexts of the situation which can change unpredictably and must be interpreted semantically to maintain proper access control. Therefore, it is necessary to have a formal representation that represents semantics of the contexts, reflects the change of the situation, and can be shared and understood by a policy system. This paper addresses these issues by introducing a context management system that uses a semantic web approach as an underlying mechanism to model and represent semantics of the contexts. The system stores current contexts in a semantic knowledge base which is used

IEEE Transactions on Knowledge and Data Engineering, 2005

Real-time update of access control policies, that is, updating policies while they are in effect and enforcing the changes immediately, is necessary for many security-critical applications. In this paper, we consider real-time update of access control policies in a database system. Updating policies while they are in effect can lead to potential security problems, such as, access to database objects by unauthorized users. In this paper, we propose several algorithms that not only prevent such security breaches but also ensure the correctness of execution. The algorithms differ from each other in the degree of concurrency provided and the semantic knowledge used. Of the algorithms presented, the most concurrency is achieved when transactions are decomposed into atomic steps. Once transactions are decomposed, the atomicity, consistency, and isolation properties no longer hold. Since the traditional transaction processing model can no longer be used to ensure the correctness of the execution, we use an alternate semantic-based transaction processing model. To ensure correct behavior, our model requires an application to satisfy a set of necessary properties, namely, semantic atomicity, consistent execution, sensitive transaction isolation, and policy-compliant. We show how one can verify an application statically to check for the existence of these properties.

2009

Mandatory access control models have traditionally been employed as a robust security mechanism in multilevel security environments such as military domains. In traditional mandatory models, the security classes associated with entities are context-insensitive. However, context-sensitivity of security classes and flexibility of access control mechanisms may be required especially in pervasive computing environments. To this aim, we propose a context-aware mandatory access control model (CAMAC) capable of dynamic adaptation of access control policies to context, and of handling context-sensitive class association, in addition to preservation of confidentiality and integrity as specified in traditional mandatory access control models. In order to prevent any ambiguity, a formal specification of the model and its elements such as context predicates, context types, level update rules, and operations is required. High expressiveness of the model allows specification of the traditional mandatory access control models such as BLP, Biba, Dion, and Chinese Wall. The model can also be considered as an information flow control model with context-sensitive association of security classes.

2018

Data privacy becomes a primary impediment to the realization of the IoT vision. One approach to the IoT security and privacy problem is to restrict access to sensitive data via access control and authorization models. Yet access context in IoT changes frequently raising the need for flexible and dynamic access control policies. Towards developing dynamic access control policies, context-based access control techniques are being investigated due to their robustness in assigning dynamic access permissions according to changes in context. In this paper, we propose to automate the generation of access control policies to overcome the inflexibility in traditional access policy specification techniques, and improve its adaptability to dynamic IoT environments. In our framework, we use context, attributes, and predication to describe the core access control elements. In response to access requests, our algorithm automatically produces conflict-free access control policies and makes the fin...

IEEE Transactions on Cloud Computing, 2019

It is generally conceded that, due to security and privacy concerns, enterprises and users are reluctant to embrace the cloud computing paradigm and hence benefit from the cost reductions and the increased flexibility or business agility that this paradigm brings about. These concerns stem mainly from the significantly-expanded attack surfaces that result from the heterogeneous nature of cloud services and the dynamicity inherent in cloud environments. In order to alleviate these concerns, effective and flexible access control approaches are required to consider the contextual parameters that characterise data access requests in the cloud. In this respect, this work presents PaaSword: a novel holistic access control framework-essentially a PaaS offering-that extends the popular XACML standard with semantic reasoning capabilities that support the federation of effective context-aware access control policies and their infusion into cloud applications with minimal manual intervention and effort. To determine the performance of our solution, a comparative evaluation test is presented and discussed, against a well-known reference implementation of the XACML standard, namely the open source WSO2 Balana engine.

Proceedings of the 7th International Conference on Cloud Computing and Services Science, 2017

By taking up the cloud computing paradigm enterprises are able to realise significant cost savings whilst increasing their agility and productivity. However, due to security concerns, many enterprises are reluctant to migrate their critical data and operations to the cloud. One way to alleviate these concerns is to devise suitable policies that infuse adequate access controls into cloud services. However, the dynamicity inherent in cloud environments, coupled with the heterogeneous nature of cloud services, hinders the formulation of effective and interoperable access control policies that are suitable for the underlying domain of application. To this end, this work proposes an ontological template for the semantic representation of context expressions in access control policies. This template is underpinned by a suitable set of interrelated concepts that generically capture a wide range of contextual knowledge that must be considered during the evaluation of policies.

Journal of Systems and Software, 2011

Securing the access to a server, guaranteeing a certain level of protection over an encrypted communication channel, executing particular counter measures when attacks are detected are examples of security requirements. Such requirements are identied based on organizational purposes and expectations in terms of resource access and availability and also on system vulnerabilities and threats. All these requirements belong to the so-called security policy. Deploying the policy means enforcing, i.e., conguring, those security components and mechanisms so that the system behavior be nally the one specied by the policy. The deployment issue becomes more dicult as the growing organizational requirements and expectations generally leave behind the integration of new security functionalities in the information system: the information system will not always embed the necessary security functionalities for the proper deployment of contextual security requirements. To overcome this issue, our solution is based on a central entity approach which takes in charge unmanaged contextual requirements and dynamically redeploys the policy when context changes are detected by this central entity.