None of the classical access control models such as DAC, MAC, RBAC, TBAC or TMAC is fully satisfactory to model security policies that are not restricted to static permissions but also include contextual rules related to permissions, prohibitions, obligations and recommendations. This is typically the case of security policies that apply to the health care domain. In this paper, we suggest a new model that provides solutions to specify such contextual security policies. This model, called Organization based access control, is presented using a formal language based on firstorder logic.

Due to physical and logical vulnerabilities, a critical infrastructure (CI) can encounter failures of various degrees of severity, and since there are many interdependencies between CIs, simple failures can have dramatic consequences on the users. In this paper, we mainly focus on malicious threats that might affect the information and communciation system that controls the Critical Infrastructure, i.e., the Critical Information Infrastructure (CII). To address the security challenges that are specific of CIIs, we propose a collaborative access control framework called PolyOrBAC. This approach offers each organization taking part in the CII the capacity of collaborating with the other ones, while maintaining a control on its resources and on its internal security policy. The interactions between organizations participating in the CII are implemented through web services (WS), and for each WS a contract is signed between the service-provider organization and the service-user organization. The contract describes the WS functions and parameters, the liability of each party and the security rules controlling the interactions. At runtime, the compliance of all interactions with these security rules is checked. Every deviation from the signed contracts triggers an alarm, the concerned parties are notified and audits can be used as evidence for sanctioning the party responsible for the deviation. Our approach is illustrated by a practical scenario, based on real emergency actions in an electric power grid infrastructure, and a simulation test bed has been implemented to animate this scenario and experiment its security issues.

Nowadays, systems are more and more open, distributed and collaborative. In this context, access control is an important issue that should be studied, specified and well enforced. This work proposes a new access control model for collaborative systems: "PolyOrBAC". On the one hand, we extend OrBAC (Organization-Based Access Control Model) to specify local as well as collaboration access control rules; on the other hand, we enforce these security policies by applying web services mechanisms (XML, SOAP, UDDI and WSDL). We thus present a representative scenario of secure collaborative applications. Furthermore, we propose a XACML-based implementation of PolyOrBAC and we discuss the most important approaches that emphasize access control in collaborative environments.

No abstract

A critical infrastructure (CI) can fail with various degrees of severity due to physical and logical vulnerabilities. Since many interdependencies exist between CIs, failures can have dramatic consequences on the entire infrastructure. This paper focuses on threats that affect information and communication systems that constitute the critical information infrastructure (CII). A new collaborative access control framework called PolyOrBAC is proposed to address security problems that are specific to CIIs. The framework offers each organization participating in a CII the ability to collaborate with other organizations while maintaining control of its resources and internal security policy. The approach is demonstrated on a practical scenario involving the electrical power grid.

No abstract

To ameliorate the quality of protection provided by intrusion detection systems (IDS) we strongly need more effective evaluation and testing procedures. Evaluating an IDS against all known and unknown attacks is probably impossible. Nevertheless, a sensible selection of representative attacks is necessary to obtain an unbiased evaluation of such systems. To help in this selection, this paper suggests applying the same approach as in software testing: to overcome the problem of an unmanageably large set of possible inputs, software testers usually divide the data input domain into categories (or equivalence classes), and select representative instances from each category as test cases. We believe that the same principle could be applied to IDS testing if we have a reasonable classification. In this paper we make a thorough analysis of existing attack classifications in order to determine whether they could be helpful in selecting attack test cases. Based on our analysis, we construct a new scheme to classify attacks relying on those attributes that appear to be the best classification criteria. The proposed classification is mainly intended to be used for testing and evaluating IDS although it can be used for other purposes such as incident handling and intrusion reporting. We also apply the Classification Tree Method (CTM) to select attack test cases. As far as we know, this is the first time that this method is applied for this purpose. General TermsSecurity

No abstract