Critical Infrastructure Systems Research Articles

Resilience assessment for interdependent urban infrastructure systems using dynamic network flow models

Critical infrastructure systems are becoming increasingly interdependent, which can exacerbate the impacts of disruptive events through cascading failures, hindered asset repairs and network congestion. Current resilience assessment methods fall short of fully capturing such interdependency effects as they tend to model asset reliability and network flows separately and often rely on static flow assignment methods. In this paper, we develop an integrated, dynamic modelling and simulation framework that combines network and asset representations of infrastructure systems and models the optimal response to disruptions using a rolling planning horizon. The framework considers dependencies pertaining to failure propagation, system-of-systems architecture and resources required for operating and repairing assets. Stochastic asset failure is captured by a scenario tree generation algorithm whereas the redistribution of network flows and the optimal deployment of repair resources are modelled using a minimum cost flow approach. A case study on London's metro and electric power networks shows how the proposed methodology can be used to assess the resilience of city-scale infrastructure systems to a local flooding incident and estimate the value of the resilience loss triangle for different levels of hazard exposure and repair capabilities.

Procedures for sensor nodes operation in the secured domain

SummaryCurrently, the networks of mobile sensor nodes, which are IoT components, are increasingly a source of data for building situational awareness. Such networks can be a source of data for critical infrastructure systems if, in addition to the timeliness (freshness) of the data, it will also be possible to ensure the reliability of these data. Such requirements are met by a secure domain of sensor nodes, in which all sensor nodes are authenticated, sensitive data is stored in protected resources of sensor nodes, and data exchange in the domain and outside the domain is cryptographically protected. This paper presents the concept of a safe domain of sensor nodes for IoT and describes the data structures necessary to ensure security in the domain and the way of protecting the resources of each node. Particular attention was paid to the procedure of preparing a sensor node for work in a secured domain of sensor nodes.

Improving repair sequence scheduling methods for postdisaster critical infrastructure systems

AbstractThe recovery process of postdisaster critical infrastructure systems (CISs) includes multiple phases, among which the repair phase usually takes the longest time and contributes the largest to system recovery rapidity and system resilience. This article formulates the repair sequence scheduling problem for damaged CIS components under limited repair resources in a general form, and then proposes two novel heuristic methods to enhance its solution performance. To demonstrate the efficiencies of the two proposed methods, typical existing methods are also briefly introduced for comparison purposes, including three component importance‐based methods (CIBMs), a genetic algorithm‐based method (GABM), a time index‐based heuristic method (TIBHM), and a component index‐based exact solution method (CIBESM). Those methods are separately applied into thousands of damage scenarios for three systems, and are then compared in terms of the optimality gap and the computational cost. Results show that the two proposed methods have significantly better performance than existing methods, whereas the first proposed method can be adapted for critical time points‐based resilience assessment and optimization, and the second proposed method can be applied to the recovery of large‐scale CISs with extensive disruptions.

A secure fog‐based platform for SCADA‐based IoT critical infrastructure

SummaryThe rapid proliferation of Internet of things (IoT) devices, such as smart meters and water valves, into industrial critical infrastructures and control systems has put stringent performance and scalability requirements on modern Supervisory Control and Data Acquisition (SCADA) systems. While cloud computing has enabled modern SCADA systems to cope with the increasing amount of data generated by sensors, actuators, and control devices, there has been a growing interest recently to deploy edge data centers in fog architectures to secure low‐latency and enhanced security for mission‐critical data. However, fog security and privacy for SCADA‐based IoT critical infrastructures remains an under‐researched area. To address this challenge, this contribution proposes a novel security “toolbox” to reinforce the integrity, security, and privacy of SCADA‐based IoT critical infrastructure at the fog layer. The toolbox incorporates a key feature: a cryptographic‐based access approach to the cloud services using identity‐based cryptography and signature schemes at the fog layer. We present the implementation details of a prototype for our proposed secure fog‐based platform and provide performance evaluation results to demonstrate the appropriateness of the proposed platform in a real‐world scenario. These results can pave the way toward the development of a more secure and trusted SCADA‐based IoT critical infrastructure, which is essential to counter cyber threats against next‐generation critical infrastructure and industrial control systems. The results from the experiments demonstrate a superior performance of the secure fog‐based platform, which is around 2.8 seconds when adding five virtual machines (VMs), 3.2 seconds when adding 10 VMs, and 112 seconds when adding 1000 VMs, compared to the multilevel user access control platform.

An adaptive robust framework for the optimization of the resilience of interdependent infrastructures under natural hazards

This paper proposes a novel adaptive robust optimization (ARO)-based mathematical framework for resilience enhancement of interdependent critical infrastructure (CI) systems against natural hazards (NHs). In this framework, the potential impacts of a specific NH on an infrastructure are firstly evaluated, in terms of failure and recovery probabilities of system components; these are, then, fed into a two-stage ARO model to determine the optimal planning of resilience strategies under limited investment budget, anticipating the most-likely worst realization of the uncertainty of component failures under the NH. For its exact solution, a decomposition method based on simultaneous column-and-constraint generation is adopted. The approach is applied to a case study concerning the resilience of interdependent power and gas networks subject to (simulated) wind storms. The numerical results demonstrate the effectiveness of the proposed framework for the optimization of the resilience of interdependent CIs under hazardous events; this provides a valuable tool for making informed pre-hazard preparation decisions. The value of a coordinated pre-hazard planning that takes into account CI interdependencies is also highlighted.

Structural and functional robustness of networked critical infrastructure systems under different failure scenarios

We analyze the structural and functional robustness of networked critical infrastructure systems (CISs). We propose a structural and functional robustness model of a typical complex network and take into account the corresponding measuring metrics and cascading processes to assess the impact of different hazard modes on robustness. We analyze the robustness of the shanghai subway network and the central China power grid to demonstrate an application of the model. We find that both are strongly robust to random failure but extremely vulnerable to targeted attack. We identify the critical areas most likely to be attack targets and use a functional perspective to identify vulnerabilities. Our proposed method can be applied to other CISs and aid in understanding the mechanisms of network robustness.

Resilience or robustness: identifying topological vulnerabilities in rail networks.

Many critical infrastructure systems have network structures and are under stress. Despite their national importance, the complexity of large-scale transport networks means that we do not fully understand their vulnerabilities to cascade failures. The research conducted through this paper examines the interdependent rail networks in Greater London and surrounding commuter area. We focus on the morning commuter hours, where the system is under the most demand stress. There is increasing evidence that the topological shape of the network plays an important role in dynamic cascades. Here, we examine whether the different topological measures of resilience (stability) or robustness (failure) are more appropriate for understanding poor railway performance. The results show that resilience, not robustness, has a strong correlation with the consumer experience statistics. Our results are a way of describing the complexity of cascade dynamics on networks without the involvement of detailed agent-based models, showing that cascade effects are more responsible for poor performance than failures. The network science analysis hints at pathways towards making the network structure more resilient by reducing feedback loops.

Extending the cyber-attack landscape for SCADA-based critical infrastructure

The move from point-to-point serial communication to traditional information technology (IT) networks has created new challenges in providing cyber-security for supervisory control and data acquisition (SCADA) systems in critical infrastructure. Current research on the attack landscape for critical infrastructure concentrates on either IT-based or protocol specific attacks. However, there is limited research focus on “the bigger picture”, the combination of IT attacks and critical infrastructure protocol attacks, and little consideration of cyber-attacks targeting an entire (SCADA)-based critical infrastructure system. Due to such narrow research, there is a complete lack of focus when comprehending full-scale cyber attacks on SCADA-based critical infrastructure systems. As a result, new attacks combining various vulnerabilities in engineering systems and IT systems are yet to be discovered.In this paper, we collated existing known attacks, identified and combined the existing range of attack landscapes, expanded and “filled the gaps” in the landscape, thus presenting a complete cyber-attack framework that perceives attacks against entire SCADA-based critical infrastructure. Our framework identifies four attack types, traditional IT-based attacks, protocol specific attacks, configuration-based attacks and control process attacks, allowing us to describe practical attacks. The benefit of recognizing the range of attacks on entire critical systems is that it allows us to defend against attacks with far greater efficiency and intelligence. To support the validity of our presented framework, we present a case study demonstrating a series of attacks on physical Distributed Network Protocol 3 (DNP3) critical infrastructure equipment.

CREATION OF METHODOLOGICAL BASIS FOR IDENTIFICATION OF SIGNIFICANT SEGMENTS FROM THE POINT OF VIEW OF PRESERVATION OF SEMANTIC INTEGRITY OF A VIDEO RESOURCE

The necessity of further improvement of technologies of effective syntactic coding of video information resources for ensuring their information security in systems of critical infrastructure is proved. It is shown that one of the stages is required to use the methods of identification of video frame segments by the degree of their saturation with structural elements. It is proved that it creates conditions for further decrease in bit volume, and consequently and increase of level of categories of availability and integrity of information resources. Development of identification of significant segments from the position of preservation of semantic integrity of video resource on the basis of use of system of rules for decision-making on information on structural and statistical properties of microsegments on a brightness component of color representation of a video frame is stated. Built a system of rules to identify segments of the video according to their degree of importance from the position maintain the necessary level of integrity of objects of interest, given the information value of local areas (these micro-segments) of the video frame, characterized by a greater homogeneity of their structural and statistical properties. The basic components of such a rule are substantiated, which include: at the first level, a system of comparisons of the indicator characterizing the level of structural and statistical saturation of microsegments with upper and lower threshold values is created. This is one of the three types of microsegment, characterized by respectively high, seredni ABO niskim runem structural statisticno nasyshennost on syntaxical run the description; the second level is the system of decision rules relative to the importance of the segment from the position of the SSTs of the video resource based on usage information about the number of these micro-segments with different levels of structural-statistical saturation. It is shown that the processing time delays are reduced due to the fact that the identification process is carried out only on the brightness component of the color representation of the video frame, which carries the main information load among the other color components.

Cybersafety: A System-theoretic Approach to Identify Cyber-vulnerabilities & Mitigations in Industrial Control Systems

Recent cyber-physical attacks, such as Stuxnet, Triton etc., have invoked an ominous realization about the lethality of such attacks and the vulnerability of critical infrastructure, including power, gas and water distribution systems. Traditional IT security-biased protection methods that narrowly focus on improving cyber hygiene are largely impotent in the face of targeted attacks by advanced cyber-adversaries. Thus, there is an urgent need to analyze the safety and security of critical infrastructure systems in an integrated, holistic fashion that leverages the physics of the cyber-physical system. System-Theoretic Accident Model & Processes (STAMP) offers a powerful, holistic, structured framework to analyze complex systems; hitherto, STAMP has been used extensively to perform safety analyses but an integrated safety and cyber-security analysis of industrial control systems (ICS) has not been published. This paper uses an actual electrical generation and distribution system of an archetypal industrial facility to demonstrate the application of a STAMP-based method – we call Cyber-safety – to identify and mitigate cyber-related vulnerabilities in ICS. The key contribution of this work is to differentiate the additional steps required to perform a holistic cyber-security analysis for an ICS of significant size and complexity and to present the analysis in a robust and structured format such that it can be emulated to analyze larger systems with many interdependent subsystems.

Failure Propagation Modeling in FMEAs for Reliability, Safety, and Cybersecurity using SysML

A method for modeling failure propagation is presented in the context of producing a Failure Modes and Effects Analysis (FMEA) from SysML with a critical infrastructure system example. The significance of the method is the modeling of failure propagation which enables not only an automated approach but significant additional analysis results that can be used to support reliability, safety, and cybersecurity. The analysis products from a tool implementing this method together with the insight and analytical benefits they provide are discussed)

КРИТЕРІЇ ПОДІБНОСТІ ЛІНГВІСТИЧНИХ МОДЕЛЕЙ

Важливою складовою лінгвістичного підходу до виявлення аномалій у часових рядах є критерій, за яким оцінюється подібність двох моделей. Наявність аномалії встановлюється шляхом порівняння моделей. Саме від вибору критеріїв залежить можливість застосування лінгвістичного підходу до аналізу часових рядів різної природи. Для вчасної реакції на ситуацію важлива швидкість виявлення аномалії. Вибір критеріїв залежить від можливості застосування мовного підходу до аналізу часових рядів різного характеру. Розглянуті основні метрики схожості текстів Геммінга, Левенштейна, Джаро-Вінклєра та ін.

A Method to Choose Between Automation and Human Operators for Recovery Actions During a Cyber Attack

As complex systems such as nuclear power plants, naval ships, critical infrastructure, and other systems become more connected to the internet and digital control interfaces, the chance of a cyber attack causing physical damage to a system and failure of the system increases. In many systems, recovery actions can prevent an incipient failure from causing a system-wide failure. This paper presents a method of determining if a human operator or an automated system is more appropriate to complete a recovery action during a cyber attack. The method is useful during the conceptual phase of system design where architecture changes have minimal impact on the cost and schedule of the system design effort. Practitioners can use the method to make cost and probability-informed decisions. A case study of a spent fuel cooling pool in a nuclear power plant is presented to illustrate the method.

Modelling critical infrastructure network interdependencies and failure

Critical infrastructures are fundamental systems that are interconnected with one another, and their interdependencies need to be modelled in order to analyse any vulnerabilities that exist in these infrastructure networks. In this work, a Leontief input-output model of the critical infrastructure systems and two physical critical infrastructure networks are developed. The input-output model serves to evaluate the interdependencies among the various infrastructure systems, while the physical infrastructure network describes the linkages within a single physical infrastructure system. This study examines the overall impact of any failures in the telecommunication infrastructure or electricity grid within the input-output interdependencies model systematically so as to evaluate the worst case scenarios based on the impact caused by one or more points of failure in the physical infrastructure.

Towards implementing scalable and reconfigurable SCADA security testbed in power system environment

The Stuxnet appears to be the very first cyber-attack upon industrial control systems. It has forced cybersecurity providers to put a lot of attention on outdated and obsolete security countermeasures of existing critical infrastructure systems due to the poor protection and security. Investigation of the effect of an attack upon the actual system is neither recommended due to the unintended consequences nor feasible on a replicated system, mainly due to the cost and the effort involved. Therefore, the SCADA cybersecurity researchers mostly rely on developing realistic SCADA testbeds for cybersecurity exercises. With that, this paper serves three goals; first, to present an overview of the electrical power grid SCADA system, as well as to describe the potential vulnerabilities and threats. Second, this paper pinpoints varied testbed research application areas, implementation requirements, and design approaches. Lastly, a scalable and reconfigurable SCADA testbed is proposed for cybersecurity practices.

Towards implementing scalable and reconfigurable SCADA security testbed in power system environment

The Stuxnet appears to be the very first cyber-attack upon industrial control systems. It has forced cybersecurity providers to put a lot of attention on outdated and obsolete security countermeasures of existing critical infrastructure systems due to the poor protection and security. Investigation of the effect of an attack upon the actual system is neither recommended due to the unintended consequences nor feasible on a replicated system, mainly due to the cost and the effort involved. Therefore, the SCADA cybersecurity researchers mostly rely on developing realistic SCADA testbeds for cybersecurity exercises. With that, this paper serves three goals; first, to present an overview of the electrical power grid SCADA system, as well as to describe the potential vulnerabilities and threats. Second, this paper pinpoints varied testbed research application areas, implementation requirements, and design approaches. Lastly, a scalable and reconfigurable SCADA testbed is proposed for cybersecurity practices.

Modelling critical infrastructure network interdependencies and failure

Critical infrastructures are fundamental systems that are interconnected with one another, and their interdependencies need to be modelled in order to analyse any vulnerabilities that exist in these infrastructure networks. In this work, a Leontief input-output model of the critical infrastructure systems and two physical critical infrastructure networks are developed. The input-output model serves to evaluate the interdependencies among the various infrastructure systems, while the physical infrastructure network describes the linkages within a single physical infrastructure system. This study examines the overall impact of any failures in the telecommunication infrastructure or electricity grid within the input-output interdependencies model systematically so as to evaluate the worst case scenarios based on the impact caused by one or more points of failure in the physical infrastructure.

Secure Internet of Things (IoT)-Based Smart-World Critical Infrastructures: Survey, Case Study and Research Opportunities

The widespread adoption of the Internet of Things (IoT) technologies has drastically increased the breadth and depth of attack surfaces in networked systems, providing new mechanisms for the intrusion. In the context of smart-world critical infrastructures and cyber-physical systems, the rapid adoption of the IoT systems and infrastructures without thorough consideration for the risks and vulnerabilities has the potential for catastrophic damage to the privacy, safety, and security of individuals and corporations. While the IoT systems have the potential to increase productivity, accountability, traceability, and efficiency, their potential weaknesses are also more abundant. In this paper, we provide critical consideration of the security of the IoT systems as applied to smart-world critical infrastructures. Particularly, we carry out a detailed assessment of vulnerabilities in IoT-based critical infrastructures from the perspectives of applications, networking, operating systems, software, firmware, and hardware. In addition, we highlight the three key critical infrastructure IoT-based cyber-physical systems, namely the smart transportation, smart manufacturing, and smart grid. Moreover, we provide a broad collection of attack examples upon each of the key applications. Furthermore, we introduce a case study, in which we assess the impacts of potential attacks on critical IoT-based systems, using the smart transportation system as an example. Finally, we provide a set of best practices and address the necessary steps to enact countermeasures for any generic IoT-based critical infrastructure system.

Cyberattacks on Critical Infrastructure: an Economic Perspective

The aim of this article is to analyze the economic aspects of cybersecurity of critical infrastructure defined as physical or virtual systems and assets that are vital to a country’s functioning and whose incapacitation or destruction would have a debilitating impact on national, economic, military and public security. The functioning of modern states, firms and individuals increasingly relies on digital or cyber technologies and this trend has also materialized in various facets of critical infrastructure. Critical infrastructure presents a new cybersecurity area of attacks and threats that requires the attention of regulators and service providers. Deploying critical infrastructure systems without suitable cybersecurity might make them vulnerable to intrinsic failures or malicious attacks and result in serious negative consequences. In this article a fuller view of costs and losses associated with cyberattacks that includes both private and external (social) costs is proposed. An application of the cost-benefit analysis or the Return on Security Investment (ROSI) indicator is presented to evaluate the worthiness of cybersecurity efforts and analyze the costs associated with some major cyberattacks in recent years. The “Identify, Protect, Detect, Respond and Recover” (IPDRR) framework of organizing cybersecurity efforts is also proposed as well as an illustration as to how the blockchain technology could be utilized to improve security and efficiency within a critical infrastructure.

Optimum post-disruption restoration under uncertainty for enhancing critical infrastructure resilience

The planning of post-disruption restoration in critical infrastructure systems often relies on deterministic assumptions such as complete information on resources and known duration of the repair tasks. In fact, the uncertainties faced by restoration activities, e.g. stemming from subjective estimates of resources and costs, are rarely considered. Thus, the solutions obtained by a deterministic approach may be suboptimal or even infeasible under specific realizations of the uncertainties. To bridge this gap, this paper investigates the effects of uncertain repair time and resources on the post-disruption restoration of critical infrastructure. Two-stage stochastic optimization provides insights for prioritizing the intensity and time allocation of the repair activities with the objective of maximizing system resilience. The inherent stochasticity is represented via a set of scenarios capturing specific realizations of repair activity durations and available resources, and their probabilities. A multi-mode restoration model is proposed that offers more flexibility than its single-mode counterpart. The restoration framework is applied to the reduced British electric power system and the results demonstrate the added value of using the stochastic model as opposed to the deterministic model. Particularly, the benefits of the proposed stochastic method increase as the uncertainty associated with the restoration process grows. Finally, decision-making under uncertainty largely impacts the optimum repair modes and schedule.