Dependable and Secure Cyber-Physical Systems by Martín Barrère
ACM Transactions on Cyber-Physical Systems, Jul 10, 2021
Cyber-Physical Systems (CPS) often involve complex networks of interconnected software and hardwa... more Cyber-Physical Systems (CPS) often involve complex networks of interconnected software and hardware components that are logically combined to achieve a common goal or mission; for example, keeping a plane in the air or providing energy to a city. Failures in these components may jeopardise the mission of the system. Therefore, identifying the minimal set of critical CPS components that is most likely to fail, and prevent the global system from accomplishing its mission, becomes essential to ensure reliability. In this article, we present a novel approach to identifying the Most Likely Mission-critical Component Set (MLMCS) using AND/OR dependency graphs enriched with independent failure probabilities. We address the MLMCS problem as a Maximum Satisfiability (MaxSAT) problem. We translate probabilities into a negative logarithmic space to linearise the problem within MaxSAT. The experimental results conducted with our open source tool LDA4CPS indicate that the approach is both effective and efficient. We also present a case study on complex aircraft systems that shows the feasibility of our approach and its applicability to mission-critical cyber-physical systems. Finally, we present two MLMCS-based security applications focused on system hardening and forensic investigations.
International Conference on Critical Information Infrastructures Security (CRITIS 2020), Sep 2020
In this paper we identify some of the particular challenges that are encountered when trying to s... more In this paper we identify some of the particular challenges that are encountered when trying to secure cyber-physical systems. We describe three of our current activities: the architecture of a system for monitoring cyber-physical systems; a new approach to modelling dependencies in such systems which leads to a measurement of the security of the system – interpreted as the least effort that an attacker has to expend to compromise the operation; and an approach to optimising the diversity of products used in a system with a view to slowing the propagation of malware. We conclude by discussing how these different threads of work contribute to meeting the challenges and identify possible avenues for future development, as well as providing some pointers to other work.
MaxSAT Evaluation 2020 (affiliated with SAT 2020), 2020
This paper presents a MaxSAT benchmark focused on the identification of Maximum Probability Minim... more This paper presents a MaxSAT benchmark focused on the identification of Maximum Probability Minimal Cut Sets (MPMCSs) in fault trees. We address the MPMCS problem by transforming the input fault tree into a weighted logical formula that is then used to build and solve a Weighted Partial MaxSAT problem. The benchmark includes 80 cases with fault trees of different size and composition as well as the optimal cost and solution for each case.
Journal of Information Security and Applications, Jun 2020
In recent years, Industrial Control Systems (ICS) have become increasingly exposed to a wide rang... more In recent years, Industrial Control Systems (ICS) have become increasingly exposed to a wide range of cyber-physical attacks, having massive destructive consequences. Security metrics are therefore essential to assess and improve their security posture. In this paper, we present a novel ICS security metric based on AND/OR graphs and hypergraphs which is able to efficiently identify the set of critical ICS components and security measures that should be compromised, with minimum cost (effort) f or an attacker, in order to disrupt the operation of vital ICS assets. Our tool, META4ICS (pronounced as metaphorics), leverages state-of-the-art methods from the field of logical satisfiability optimisation and MAX-SAT techniques in order to achieve efficient computation times. In addition, we present a case study where we have used our system to analyse the security posture of a realistic Water Transport Network (WTN).
50th IEEE/IFIP International Conference on Dependable Systems and Networks (DSN 2020), 2020
In this paper, we present a novel MaxSAT-based technique to compute Maximum Probability Minimal C... more In this paper, we present a novel MaxSAT-based technique to compute Maximum Probability Minimal Cut Sets (MPMCSs) in fault trees. We model the MPMCS problem as a Weighted Partial MaxSAT problem and solve it using a parallel SAT-solving architecture. The results obtained with our open source tool indicate that the approach is effective and efficient.
6th International Symposium for ICS & SCADA Cyber Security Research 2019 (ICS-CSR), 2019
Over the last years, Industrial Control Systems (ICS) have become increasingly exposed to a wide ... more Over the last years, Industrial Control Systems (ICS) have become increasingly exposed to a wide range of cyber-physical threats. Efficient models and techniques able to capture their complex structure and identify critical cyber-physical components are therefore essential. AND/OR graphs have proven very useful in this context as they are able to semantically grasp intricate logical interdependencies among ICS components. However, identifying critical nodes in AND/OR graphs is an NP-complete problem. In addition, ICS settings normally involve various cyber and physical security measures that simultaneously protect multiple ICS components in overlapping manners, which makes this problem even harder. In this paper, we present an extended security metric based on AND/OR hypergraphs which efficiently identifies the set of critical ICS components and security measures that should be compromised, with minimum cost (effort) for an attacker, in order to disrupt the operation of vital ICS assets. Our approach relies on MAX-SAT techniques, which we have incorporated in META4ICS, a Java-based security metric analyser for ICS. We also provide a thorough performance evaluation that shows the feasibility of our method. Finally, we illustrate our methodology through a case study in which we analyse the security posture of a realistic Water Transport Network (WTN).
MaxSAT Evaluation 2019 (affiliated with SAT 2019), 2019
This paper presents a MaxSAT benchmark focused on identifying critical nodes in AND/OR graphs. We... more This paper presents a MaxSAT benchmark focused on identifying critical nodes in AND/OR graphs. We use AND/OR graphs to model Industrial Control Systems (ICS) as they are able to semantically grasp intricate logical interdependencies among ICS components. However, identifying critical nodes in AND/OR graphs is an NP-complete problem. We address this problem by efficiently transforming the input AND/OR graph-based model into a weighted logical formula that is then used to build and solve a Weighted Partial MaxSAT problem. The benchmark includes 80 cases with AND/OR graphs of different size and composition as well as the optimal cost and solution for each case.
https://arxiv.org/abs/1905.04796, 2019
In recent years, Industrial Control Systems (ICS) have become an appealing target for cyber attac... more In recent years, Industrial Control Systems (ICS) have become an appealing target for cyber attacks, having massive destructive consequences. Security metrics are therefore essential to assess their security posture. In this paper, we present a novel ICS security metric based on AND/OR graphs that represent cyber-physical dependencies among network components. Our metric is able to efficiently identify sets of critical cyber-physical components, with minimal cost for an attacker, such that if compromised, the system would enter into a non-operational state. We address this problem by efficiently transforming the input AND/OR graph-based model into a weighted logical formula that is then used to build and solve a Weighted Partial MAX-SAT problem. Our tool, META4ICS, leverages state-of-the-art techniques from the field of logical satisfiability optimisation in order to achieve efficient computation times. Our experimental results indicate that the proposed security metric can efficiently scale to networks with thousands of nodes and be computed in seconds. In addition, we present a case study where we have used our system to analyse the security posture of a realistic water transport network. We discuss our findings on the plant as well as further security applications of our metric.
Proceedings of the 24th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA2018), 2018
Monitoring systems are essential to understand and control the behaviour of systems and networks.... more Monitoring systems are essential to understand and control the behaviour of systems and networks. Cyber-physical systems (CPS) are particularly delicate under that perspective since they involve real-time constraints and physical phenomena that are not usually considered in common IT solutions. Therefore, there is a need for publicly available monitoring tools able to contemplate these aspects. In this poster/demo, we present our initiative, called CPS-MT, towards a versatile, real-time CPS monitoring tool, with a particular focus on security research. We first present its architecture and main components, followed by a MiniCPS-based case study. We also describe a performance analysis and preliminary results. During the demo, we will discuss CPS-MT's capabilities and limitations for security applications.
Attack Graphs by Martín Barrère
In Proceedings of the 5th IEEE Conference on Communications and Network Security (CNS’17), October 9-11, 2017, Las Vegas, USA., 2017
Attack graphs constitute a powerful security tool aimed at modelling the many ways in which an at... more Attack graphs constitute a powerful security tool aimed at modelling the many ways in which an attacker may compromise different assets in a network. Despite their usefulness in several security-related activities (e.g. hardening, monitoring, forensics), the complexity of these graphs can massively grow as the network becomes denser and larger, thus defying their practical usability. In this presentation, we first describe some of the problems that currently challenge the practical use of attack graphs. We then explain our approach based on core attack graphs, a novel perspective to address attack graph complexity. Finally, we present Naggen, a tool for generating, visualising and exploring core attack graphs. We use Naggen to show the advantages of our approach on different security applications.
In Proceedings of the 13th IEEE International Conference on Network and Service Management (CNSM’17), November 26-30, 2017, Tokyo, Japan., 2017
In this paper, we describe an efficient methodology to guide investigators during network forensi... more In this paper, we describe an efficient methodology to guide investigators during network forensic analysis. To this end, we introduce the concept of core attack graph, a compact representation of the main routes an attacker can take towards specific network targets. Such compactness allows forensic investigators to focus their efforts on critical nodes that are more likely to be part of attack paths, thus reducing the overall number of nodes (devices, network privileges) that need to be examined. Nevertheless, core graphs also allow investigators to hierarchically explore the graph in order to retrieve different levels of summarised information. We have evaluated our approach over different network topologies varying parameters such as network size, density, and forensic evaluation threshold. Our results demonstrate that we can achieve the same level of accuracy provided by standard logical attack graphs while significantly reducing the exploration rate of the network.
Attack graphs are a powerful tool for security risk assessment by analysing network vulnerabiliti... more Attack graphs are a powerful tool for security risk assessment by analysing network vulnerabilities and the paths attackers can use to compromise network resources. The uncertainty about the attacker's behaviour makes Bayesian networks suitable to model attack graphs to perform static and dynamic analysis. Previous approaches have focused on the formalization of attack graphs into a Bayesian model rather than proposing mechanisms for their analysis. In this paper we propose to use efficient algorithms to make exact inference in Bayesian attack graphs, enabling the static and dynamic network risk assessments. To support the validity of our approach we have performed an extensive experimental evaluation on synthetic Bayesian attack graphs with different topologies, showing the computational advantages in terms of time and memory use of the proposed techniques when compared to existing approaches.
Autonomic Knowledge Discovery by Martín Barrère
IJCAI / FCA4AI 2015 -- Proceedings of the 4th International Conference on What Can FCA Do for Artificial Intelligence?, 2015
Over the last years, computer networks have evolved into highly dynamic and interconnected enviro... more Over the last years, computer networks have evolved into highly dynamic and interconnected environments, involving multiple heterogeneous devices and providing a myriad of services on top of them. This complex landscape has made it extremely difficult for security administrators to keep accurate and be effective in protecting their systems against cyber threats. In this paper, we describe our vision and scientific posture on how artificial intelligence techniques and a smart use of security knowledge may assist system administrators in better defending their networks. To that end, we put forward a research roadmap involving three complimentary axes, namely, (I) the use of FCA-based mechanisms for managing configuration vulnerabilities, (II) the exploitation of knowledge representation techniques for automated security reasoning, and (III) the design of a cyber threat intelligence mechanism as a CKDD process. Then, we describe a machine-assisted process for cyber threat analysis which provides a holistic perspective of how these three research axes are integrated together.
Over the last years, computer networks have evolved into highly dynamic and interconnected enviro... more Over the last years, computer networks have evolved into highly dynamic and interconnected environments, involving multiple heterogeneous devices and providing a myriad of services on top of them. This complex landscape has made it extremely difficult for security administrators to keep accurate and be effective in protecting their systems against cyber threats. In this paper, we describe our vision and scientific posture on how artificial intelligence techniques and a smart use of security knowledge may assist system administrators in better defending their networks. To that end, we put forward a research roadmap involving three complimentary axes, namely, (I) the use of FCA-based mechanisms for managing configuration vulnerabilities, (II) the exploitation of knowledge representation techniques for automated security reasoning, and (III) the design of a cyber threat intelligence mechanism as a CKDD process. Then, we describe a machine-assisted process for cyber threat analysis which provides a holistic perspective of how these three research axes are integrated together.
Vulnerability Management in Autonomic Networks by Martín Barrère
Accepted for publication in IEEE Communications Surveys & Tutorials, 2013.
Autonomic networks and services are exposed to a large variety of security risks. The vulnerabili... more Autonomic networks and services are exposed to a large variety of security risks. The vulnerability management process plays a crucial role for ensuring their safe configurations and preventing security attacks. We focus in this survey on the assessment of vulnerabilities in autonomic environments. In particular, we analyze current methods and techniques contributing to the discovery, the description and the detection of these vulnerabilities. We also point out important challenges that should be faced in order to fully integrate this process into the autonomic management plane.
In Proceedings of the IEEE/IFIP International Network Operations and Management Symposium (NOMS'14), Mini-Conference, May 5-9, 2014, Krakow, Poland.
Computer and network systems are consistently exposed to security threats, making their managemen... more Computer and network systems are consistently exposed to security threats, making their management even more complex. The management of known vulnerabilities plays a crucial role for ensuring their safe configurations and preventing security attacks. However, this activity should not generate new vulnerable states. In this paper we present a novel approach for autonomously assessing and remediating vulnerabilities. We describe a detailed mathematical model that supports this activity and we formalize the remediation decision process as a SAT problem. We present a framework that is able to assess OVAL vulnerability descriptions and perform corrective actions by using XCCDF-based descriptions of future machine states and the NETCONF protocol. We also provide details of our implementation and evaluate its feasibility through a comprehensive set of experiments.
In Proceedings of the 9th IEEE International Conference on Network and Service Management (CNSM'13), October 14-18, 2013, Zürich, Switzerland.
The development of mobile technologies and services has contributed to the large-scale deployment... more The development of mobile technologies and services has contributed to the large-scale deployment of smartphones and tablets. These environments are exposed to a wide range of security attacks and may contain critical information about users such as contact directories and phone calls. Assessing configuration vulnerabilities is a key challenge for maintaining their security, but this activity should be performed in a lightweight manner in order to minimize the impact on their scarce resources. In this paper we present a novel approach for assessing configuration vulnerabilities in mobile devices by using a probabilistic cost-efficient security framework. We put forward a probabilistic assessment strategy supported by a mathematical model and detail our assessment framework based on OVAL vulnerability descriptions. We also describe an implementation prototype and evaluate its feasibility through a comprehensive set of experiments.
In Proceedings of the IFIP/IEEE International Symposium on Integrated Network Management (IM'13), May 27-31, 2013, Ghent, Belgium.
Vulnerability assessment activities usually analyze new security advisories over current running ... more Vulnerability assessment activities usually analyze new security advisories over current running systems. However, a system compromised in the past by a vulnerability unknown at that moment may still constitute a potential security threat in the present. Accordingly, past unknown system exposures are required to be taken into account. We present in this paper a novel approach for increasing the overall security of computing systems by identifying past hidden vulnerable states. In that context, we propose a modeling for detecting unknown past system exposures as well as an OVAL-based distributed framework for autonomously gathering network devices information and automatically analyzing their past security exposure. We also describe an implementation prototype and evaluate its performance through an extensive set of experiments.
In Proceedings of the IFIP/IEEE International Symposium on Integrated Network Management (IM'13), May 27-31, 2013, Ghent, Belgium.
Mobile computing devices and the services offered by them are utilized by millions of users on a ... more Mobile computing devices and the services offered by them are utilized by millions of users on a daily basis. However, they operate in hostile environments getting exposed to a wide variety of threats. Accordingly, vulnerability management mechanisms are highly required. We present in this demo a novel approach for increasing the security of mobile devices by efficiently detecting vulnerable configurations. In that context, we propose Ovaldroid, an OVAL-based distributed framework for ensuring safe configurations within the Android platform and we present an implementation prototype developed to this end.
Demonstration Sessions of the IFIP/IEEE International Symposium on Integrated Network Management (IM'13), May 27-31, 2013, Ghent, Belgium.
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Dependable and Secure Cyber-Physical Systems by Martín Barrère
Attack Graphs by Martín Barrère
Autonomic Knowledge Discovery by Martín Barrère
Vulnerability Management in Autonomic Networks by Martín Barrère