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Ziad Ismaïl, Jean Leneutre, Alia Fourati

Security of Industrial Control Systems and Cyber Physical Systems (Springer). Pages: 157-167, Sep. 2015.
DOI: 10.1007/978-3-319-40385-4_11

Abstract: The improved communication and remote control capabilities of industrial control systems equipment have increased their attack surface. As a result, managing the security risk became a challenging task. The consequences of attacks in an industrial control system can go beyond targeted equipment to impact services in the industrial process. In addition, the success likelihood of an attack is highly correlated to the attacker profile and his knowledge of the architecture of the system. In this paper, we present the Attack Execution Model (AEM), which is an attack graph representing the evolution of the adversary’s state in the system after each attack step. We are interested in assessing the risk of cyber attacks on an industrial control system before the next maintenance period. Given a specific attacker profile, we generate all potential attacker actions that could be executed in the system. Our tool outputs the probability and the time needed to compromise a target equipment or services in the system.

Ziad Ismaïl, Danai Symeonidou, Fabian Suchanek

Proceedings of the 24th International Conference on World Wide Web (ACM). Pages: 203-206, May 2015.
DOI: 10.1145/2740908.2742836

Abstract: Internet users typically have several online accounts – such as mail accounts, cloud storage accounts, or social media accounts. The security of these accounts is often intricately linked: The password of one account can be reset by sending an email to another account; the data of one account can be backed up on another account; one account can only be accessed by two-factor authentication through a second account; and so forth. This poses three challenges: First, if a user loses one or several of his passwords, can he still access his data? Second, how many passwords does an attacker need in order to access the data? And finally, how many passwords does an attacker need in order to irreversibly delete the user’s data? In this paper, we model the dependencies of online accounts in order to help the user discover security weaknesses. We have implemented our system and invite users to try it out on their real accounts.

Ziad Ismaïl, Jean Leneutre, David Bateman, Lin Chen

Proceedings of the 16th International Symposium on High Assurance Systems Engineering (IEEE). Jan. 2015.
DOI: 10.1109/HASE.2015.24

Abstract: The communication infrastructure is a key element for management and control of the power system in the smart grid. The communication infrastructure, which can include equipment using off-the-shelf vulnerable operating systems, has the potential to increase the attack surface of the power system. The interdependency between the communication and the power system renders the management of the overall security risk a challenging task. In this paper, we address this issue by presenting a mathematical model for identifying and hardening the most critical communication equipment used in the power system. Using non-cooperative game theory, we model interactions between an attacker and a defender. We derive the minimum defense resources required and the optimal strategy of the defender that minimizes the risk on the power system. Finally, we evaluate the correctness and the efficiency of our model via a case study.

Rim Kaddah, Daniel Kofman, Michal Pioro

Proceedings of the International Workshop on Intelligent Energy Systems (IEEE). Oct. 2014.
DOI: 10.1109/IWIES.2014.6957044

Abstract: We consider demand response solutions having the capability to monitor different variables at users’ premises, like presence and temperature, and to control individual appliances. We focus on the optimal control of the appliances during time periods where the available capacity is not enough to satisfy the demand generated by houses operating freely. We propose an approach to define the utility of appliances as a function of monitored variables, as well as control schemes to optimize this utility. Global optimums can be reached when a centralized entity (i.e., an aggregator) can gather information from each user and control each individual appliance. This may not be always possible, for example for privacy and/or scalability reasons. We therefore consider, in addition, a system where decisions are taken partially at a centralized site (global power allocation per home) and partially at customer premises (sharing of the allocated power among local appliances). Performances of proposed control mechanisms are evaluated and compared. We show the potential value of introducing demand response mechanisms at fine granularity.

Rayhana Baghli, Bruno Traverson

Proceedings of the 2nd International Conference on Model-Driven Engineering and Software Development (SCITEPRESS). Jan. 2014.

Abstract: Business rules are defined, specified and validated by business experts but they are designed and implemented by technical implementers. Each of them uses languages adapted to their activity and skill. Verbalization of business rules permits to business experts to get a semi-natural expression of rules designed by technical implementers thus facilitating their task of validation. A transformation tool is proposed to automate verbalization and applied to OCL (Object Constraint Language) constraints in the Utility domain.