Dynamic deployment of context-aware access control policies for constrained security devices

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 identi ed 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., con guring, those security components and mechanisms so that the system behavior be nally the one speci ed by the policy. The deployment issue becomes more di cult 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. We also present an improvement over the OrBAC (Organization-Based Access Control) model. Up to now, a controller based on a contextual OrBAC policy is passive, in the sense that it assumes policy evaluation triggered by access requests. Therefore, it does not allow reasoning about policy state evolution when actions occur. The modi cations introduced by our work overcome this limitation and provide a proactive version of the model by integrating concepts from action speci cation languages

Graph Transformations for the Specification of Access Control Policies

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A System For Visual Role-Based Policy Modelling

The definition of security policies in information systems and programming applications is often accomplished through traditional low level languages that are difficult to use. This is a remarkable drawback if we consider that security policies are often specified and maintained by top level enterprise managers who would probably prefer to use simplified, metaphor oriented policy management tools. To support all the different kinds of users we propose a suite of visual languages to specify access and security policies according to the role based access control (RBAC) model. Moreover, a system implementing the proposed visual languages is proposed. The system provides a set of tools to enable a user to visually edit security policies and to successively translate them into (eXtensible Access Control Markup Language) code, which can be managed by a Policy Based Management System supporting such policy language. The system and the visual approach have been assessed by means of usability studies and of several case studies. The one presented in this paper regards the configuration of access policies for a multimedia content management platform providing video streaming services also accessible through mobile devices

An Evolutionary Approach for Learning Attack Specifications in Network Graphs

This paper presents an evolutionary algorithm that learns attack scenarios, called attack specifications, from a network graph. This learning process aims to find attack specifications that minimise cost and maximise the value that an attacker gets from a successful attack. The attack specifications that the algorithm learns are represented using an approach based on Hoare's CSP (Communicating Sequential Processes). This new approach is able to represent several elements found in attacks, for example synchronisation. These attack specifications can be used by network administrators to find vulnerable scenarios, composed from the basic constructs Sequence, Parallel and Choice, that lead to valuable assets in the network

Generating Preconditions from Graph Constraints by Higher Order Graph Transformation

Techniques for the verification of structural invariants in graph transformation systems typically rely on the derivation of negative application conditions that are attached to graph transformation rules in order to avoid the runtime occurrence of forbidden structural patterns in the system model. In this paper, we propose a practical approach for this derivation process, which produces the required negative application conditions by applying higher order graph transformation on the rule specifications themselves. Additionally, we integrate filtering criteria into these higher order constructs to avoid already at an early stage the unnecessary construction of invalid and redundant rules with negative application conditions