An Effective Security Requirements Engineering Framework for Cyber-Physical Systems

Security is an important feature of the software. Integrating security requirements right at the beginning not only ensure secure software but also save a lot of precious time and reduce the effort of rework of software development team. However, to build a secure system is not an easy task and it is extremely difficult to develop a secure system, especially in the case of cyber-physical systems (CPS). In this paper, we propose a security requirements engineering framework that provides ways to determine security requirements throughout the requirements engineering phase which consists of a number of activities to elicit and finalize the security requirements for CPS. Additionally, we determine the activities that need to be implemented in the security requirements engineering framework to address security requirements for CPS. We compare our proposed security requirements engineering framework with other existing software security frameworks. The result shows that not all software security frameworks perform all the basic and important activities in the development of secure software systems. This may also result in a development of an unsecure cyber-physical systems. Furthermore, this comparison survey helps us to identify the short-comings in SRE frameworks which has been rectified in our proposed security requirements engineering framework for CPS.

Given the wide distribution of software and its current growth, security is inevitable, and software systems have become more complex. To avoid the complexity and protect valuable assets of software systems, researchers, and practitioners in the fields of security requirement engineering (SRE) and security assurance advise incorporating security requirements early in software development life cycle (SDLC). Nowadays, security requirements specification and identification are an active research area for ensuring the effectiveness of software systems. However, security requirement identification is a challenging task due to sheer numbers of threats and attacks to a software system. Previous researchers have identified different SRE techniques, each looking at the same problem from a different perspective. Therefore, a literature review conducted on SRE techniques. We compared and analyzed different SRE techniques to find the most suitable SRE techniques for researchers and practitioners. Selected SRE techniques compared based on various parameters, such as different attributes, requirement elicitation, requirement analysis, project size, and integration of standards. The literature also indicates that among SRE approaches, security quality requirements engineering (SQAURE), secure tropos, security requirements engineering process (SREP), and comprehensive lightweight application security process (CLASP) are the most used SRE approaches that focus on activities such as threats, security requirements identification, and security objectives identification. Unfortunately, several SRE approaches fail to explicitly integrate the security standard and security assurance perspective. Three questions developed for this study: Question 1 is based on comparison of existing SRE approaches, Question 2 is based on SRE with security requirements elicitation and analysis, and Question 3 highlights the incorporation of security requirements assurance by SRE approaches implicitly or explicitly. The researcher must work with the developer to easily adopt SRE approaches to elicit and ensure security requirements for the software system.

The article focuses on studying and implementing a method of assigning access rights to the applications in a corporate mobile network with different requirements for security, which will allow considering the specific activities of multiple users. The existing solutions for assigning access rights to applications and services of the intranet are analyzed, the need to create a method that ensures information security when implementing access in corporate networks with different requirements for the level of security is substantiated. Due to the results of analysis of trends and development prospects of modern corporate mobile networks there has been found a contradiction between the requirements for information security of universal mobile devices with access to secure services and technical capabilities of information security systems that ensure access security in the corporate networks with different security requirements. To solve the problem, a multi-user system has been implemented that ensures operation of any computer equipment and mobile devices of an organization whose DBMS has a client-server architecture. The functional requirements for the developed method include the ability to perform user authorization, providing the administrator with the ability to manage user access rights to various applications, managing application storage, recording user operations, and keeping records. In the course of the software implementation of the method of assigning access rights, the design of the database is described in stages, a model of information flows is built, a physical diagram of the interaction of individual procedures is considered, on the basis of which the database is created, a user interface with forms that display information stored in the database is developed.

Guest Editorial

Modeling Security and Privacy Requirements: a Use Case-Driven Approach

With networks increasingly moving into virtually every aspect of our daily life, security is gaining importance, not only from the traditional perspective of communication but the network's growing role in modern automation and control. The traditional, certification based approach attempts to guarantee the security of a network through certification. Certified networks are generally confined to a limited domain and, as a result, they are isolated, costly, and under-utilized. In contrast, this paper presents a new principle – user-level, security-on-demand system, wherein the network allocates, where possible, the security resources commensurate with the user's request for transporting message(s) through the network securely. This principle is successfully demonstrated for the current Asynchronous Transfer Mode (ATM) networks, and is the result of an integration of the fundamental framework for network security, recently proposed by the authors in the literature, with the unique characteristics of ATM networks. The framework encapsulates the fundamental knowledge and set of relationships in network security and permits scientific and systematic reasoning about network security. It also enables all user groups – military, government, industry, and academia, to define their security requirements in a uniform manner. The security-on-demand approach promises the development of a "mixed use" class of networks in the future that may be simultaneously shared by different groups of users, with the system sustaining the diverse security requirements of each user. A unique characteristic in ATM network design is the dynamic call setup process. Under it, a network first establishes a virtual path or route for a user's call, guided by the user's requirements, and then transports the messages when a route has been successfully determined. This unique ATM characteristic is integrated with the framework to yield a successful demonstration of the proposed, user-level, security-on-demand approach. Utilizing the security framework as the foundation, every element of the network – node and link, is characterized by a security matrix that reflects its security resources. Every user is permitted to specify the security requirement for the call through a matrix, which expresses the limits of the security resources that the traffic cells must encounter during their transport through the network. Thus, during the dynamic establishment of the virtual path, every node and link is examined to ensure that the user-specified security is met, in addition to bandwidth and other Quality of Service (QoS) requirements. Traffic is launched when the call setup succeeds, otherwise, the call fails. Like all networks, the ATM network inherently consists of geographically dispersed entities and, as a result, the resource allocation strategy is necessarily distributed. Furthermore, as the network operation progresses, the resource availability scene changes dynamically. This paper proposes a unique function that reduces the key network resource parameters at a node to a single value, termed Node Status Indicator (NSI). The NSI value is computed dynamically at every node and disseminated across the network to be utilized by a node to refine its determination of a virtual path for a user call. The aim of the NSI is to improve the resource utilization in the network. The proposed approach is modeled for a large-scale, representative, 40-node ATM network. Utilizing stochastic input traffic that is synthesized to reflect realistic operating conditions, the model is simulated extensively on a testbed of 35+ Pentium workstations, under Linux, configured as a loosely-coupled parallel processor, utilizing an accurate, asynchronous, distributed simulator. The simulator implements the key characteristics of the ATM Forum proposed P-NNI 1.0 and UNI 3.0 standards. While the simulation results reflect a successful realization of the proposed approach, analysis reveals minimal impact of incorporating security on ATM network performance, as measured through call success rates and call setup times. In contrast, the tradition has been to incorporate security into large-scale systems and networks as an afterthought, i.e. adding hardware and software devices after the design has been completed, resulting in performance degradation. Also, while the use of NSI is observed to yield slightly lower average call setup rates and slightly higher average call setup times, a careful analysis of the trace of the calls as they progress through the system, reveals that, in general, calls are dispersed throughout the network, seeking to utilize all available resources of the network more evenly.

High integration of distributed energy resources raises the challenge of reliable operation to power system operators. In order to improve the ability to monitor and control power systems, automation systems are necessary. However, the operational flexibility of automation systems to deal with abnormal situations is currently limited. In this regard, virtualization as a key enabling technology to improve the operational flexibility in Cyber-Physical Energy Systems has been proposed. To this end, grid services (e.g. state estimation, coordinated voltage control), which are traditionally bound to hardware, are separated from underlying computation platforms. This provides modularity and isolation of grid services, which enables monitoring, managing and deploying them independently. However, virtualizing grid services, resulting in increased system complexity, can cause new security concerns. This paper analyzes virtualized Cyber-Physical Energy Systems from a security viewpoint and identifies associated security threats. Based on security requirements and potential solutions addressed by IEC 62351 security standard, a set of studies is conducted to analyze the effect of traditional security mechanisms, when applied to virtualized Cyber-Physical Energy Systems. Finally, possible software solutions and recommendations that protect the system against threats are proposed. Future research directions and open problems are stated at the end.

This paper presents a cyber-physical systems modelling language for capturing and describing health-based critical infrastructures. Following this practice incident response plan developers are able to model and reason about security and recovery issues in medical cyber-physical systems from a security requirements engineering perspective. Our work builds upon concepts from the Secure Tropos methodology, where in this paper we introduce novel cyber-physical concepts, relationships and properties in order to carry out analysis of incident response plans based on security requirements. We illustrate our concepts through a case study of a radiological department’s medical cyber-physical systems that have been infected with the WannaCry ransomware. Finally, we discuss how our modelling language enriches security models with incident response concepts, guiding plan developers of health-based critical infrastructures in understanding cyber-physical systems vulnerabilities and support decision making at a tactical and a strategic level, through semi-automated secure recovery analysis.

The security of Cyber-Physical Systems (CPS) and the Internet of Things (IoT) is a significant issue due to the increasing integration of these systems into critical infrastructure, production and other industrial environments, as well as the growing use of IoT devices in various areas of life. It is therefore important to consider the security challenges in these systems and work on their resolution in order to maintain the stability and reliability of these systems. This paper discusses the security of CPS and IoT systems, including the architecture of such systems, security requirements and standards, as well as specific security issues that arise in both types of systems. In particular, CPS security is considered through the physical interface, control system, availability and time constraints, while IoT security is considered through trust management, secure routing protocols, integration of heterogeneous networks and privacy protection.

Cyber-physical systems (CPSs), due to their direct influence on the physical world, have to meet extended security and dependability requirements. This is particularly true for CPS that operate in close proximity to humans or that control resources that, when tampered with, put all our lives at stake. In this paper, we review the challenges and some early solutions that arise at the architectural and operating-system level when we require cyber-physical systems and CPS infrastructure to withstand advanced and persistent threats. We found that although some of the challenges we identified are already matched by rudimentary solutions, further research is required to ensure sustainable and dependable operation of physically exposed CPS infrastructure and, more importantly, to guarantee graceful degradation in case of malfunction or attack.

Over the years, important breakthroughs have been made in protecting data at rest or in-transit. The emergence of the Internet of Things (IoT) and Cyber Physical Systems (CPS) has pose new challenges for protecting data in systems and devices tightly close to humans. Embedded systems with constrained computing capabilities are a central part in IoT and CPS, susceptible to different security attacks and vulnerabilities. Lightweight cryptography is the term used for grouping the different cryptographic algorithms and techniques tailored to observe the requirements for data security in such constrained applications. Nowadays, the potential emergence of quantum computing threatens these security solutions widely in use. Thus, novel cryptographic algorithms deemed to resist quantum attack models are being standardized by the National Institute of Standards and Technology (NIST) in the Post-Quantum Cryptography (PQC) Standardization process. In this paper, we present a study on how the advent of quantum computing might have a deep impact on the security of constrained applications in the IoT and CPS domains. We focused on the NIST PQC finalists, from the perspective of their use for securing embedded systems.

Cyber Physical Systems (CPS) are characterized by their ability to integrate\nthe physical and information or cyber worlds. Their deployment in critical\ninfrastructure have demonstrated a potential to transform the world. However,\nharnessing this potential is limited by their critical nature and the far\nreaching effects of cyber attacks on human, infrastructure and the environment.\nAn attraction for cyber concerns in CPS rises from the process of sending\ninformation from sensors to actuators over the wireless communication medium,\nthereby widening the attack surface. Traditionally, CPS security has been\ninvestigated from the perspective of preventing intruders from gaining access\nto the system using cryptography and other access control techniques. Most\nresearch work have therefore focused on the detection of attacks in CPS.\nHowever, in a world of increasing adversaries, it is becoming more difficult to\ntotally prevent CPS from adversarial attacks, hence the need to focus on making\nCPS resilient. Resilient CPS are designed to withstand disruptions and remain\nfunctional despite the operation of adversaries. One of the dominant\nmethodologies explored for building resilient CPS is dependent on machine\nlearning (ML) algorithms. However, rising from recent research in adversarial\nML, we posit that ML algorithms for securing CPS must themselves be resilient.\nThis paper is therefore aimed at comprehensively surveying the interactions\nbetween resilient CPS using ML and resilient ML when applied in CPS. The paper\nconcludes with a number of research trends and promising future research\ndirections. Furthermore, with this paper, readers can have a thorough\nunderstanding of recent advances on ML-based security and securing ML for CPS\nand countermeasures, as well as research trends in this active research area.\n

The article discusses trends and approaches to the development of industrial cyber-physical systems, highlighted the requirements for such systems. The main methods of increasing the computational performance of processors in embedded systems and the latest approaches used in computing, such as heterogeneous computing and increasing the number of processor cores for parallel execution of operations, are considered. The issue of security of cyber-physical systems in the post-quantum era and methods of hardware implementation of quantum-resistant encryption algorithms based on lattice theory that meet performance and security requirements are considered separately. Methods for improving the reliability of embedded systems and expanding functionality using field programmable gate arrays are also described. The advantages of the RISC-V (reduced instruction set computer) core architecture for embedded systems are considered. Based on the requirements, a microcontroller architecture based on RISC-V is proposed, which uses the principle of heterogeneous computing to increase performance, meeting the requirements of modern equipment for industrial cyber-physical systems.

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