Designed-in security for cyber-physical systems

An expert from academia, one from a cyber-physical system (CPS) provider, and one from an end asset owner and user offer their different perspectives on the meaning and challenges of 'designed-in security.' The academic highlights foundational issues and talks about emerging technology that can help us design and implement secure software in CPSs. The vendor's view includes components of the academic view but emphasizes the secure system development process and the standards that the system must satisfy. The user issues a call to action and offers ideas that will ensure progress

Cyber-Physical Security Strategies

Cyber-physical security describes the protection of systems with close relationships between computational functions and physical ones and addresses the issue of vulnerability to attack through both cyber and physical avenues. This describes systems in a wide variety of functions, many crucial to the function of modern society, making their security of paramount importance. The development of secure system design and attack detection strategies for each potential avenue of attack is needed to combat malicious attacks. This thesis will provide an overview of the approaches to securing different aspect of cyber-physical systems. The cyber element can be designed to better prevent unauthorized entry and to be more robust to attack while its use is evaluated for signs of ongoing intrusion. Nodes in sensor networks can be evaluated by their claims to determine the likelihood of their honesty. Control systems can be designed to be robust in cases of the failure of one component and to detect signal insertion or replay attack. Through the application of these strategies, the safety and continued function of cyber-physical systems can be improved

An analysis of security issues in building automation systems

The purpose of Building Automation Systems (BAS) is to centralise the management of a wide range of building services, through the use of integrated protocol and communication media. Through the use of IP-based communication and encapsulated protocols, BAS are increasingly being connected to corporate networks and also being remotely accessed for management purposes, both for convenience and emergency purposes. These protocols, however, were not designed with security as a primary requirement, thus the majority of systems operate with sub-standard or non-existent security implementations, relying on security through obscurity. Research has been undertaken into addressing the shortfalls of security implementations in BAS, however defining the threats against BAS, and detection of these threats is an area that is particularly lacking. This paper presents an overview of the current security measures in BAS, outlining key issues, and methods that can be improved to protect cyber physical systems against the increasing threat of cyber terrorism and hacktivism. Future research aims to further evaluate and improve the detection systems used in BAS through first defining the threats and then applying and evaluating machine learning algorithms for traffic classification and IDS profiling capable of operating on resource constrained BAS

Anomaly detection based on zone partition for security protection of industrial cyber-physical systems

A developing trend of traditional industrial systems is the integration of the cyber and physical domain to improve flexibility and the efficiency of supervision, management and control. But, the deep integration of these Industrial Cyber-Physical Systems (ICPSs), increases the potential for security threats. Attack detection, which forms initial protective barrier, plays an important role in overall security protection. However, most traditional methods focused on cyber information and ignored any limitations that might arise from the characteristics of the physical domain. In this paper, an anomaly detection approach based on zone partition is designed for ICPSs. In detail, initially an automated zone partition method ensuring crucial system states can be observed in more than one zone is designed. Then, methods of building zone function model which do not require any prior knowledge of the physical system are presented before analyzing the anomaly based on zone information. Finally, an experimental rig is constructed to verify the effectiveness of the proposed approach. The results demonstrate that the approach presents a high accuracy solution which also performs effectively in realtime

Process-Aware Defenses for Cyber-Physical Systems

The increasing connectivity is exposing safety-critical systems to cyberattacks that can cause real physical damage and jeopardize human lives. With billions of IoT devices added to the Internet every year, the cybersecurity landscape is drastically shifting from IT systems and networks to systems that comprise both cyber and physical components, commonly referred to as cyber-physical systems (CPS). The difficulty of applying classical IT security solutions in CPS environments has given rise to new security techniques known as process-aware defense mechanisms, which are designed to monitor and protect industrial processes supervised and controlled by cyber elements from sabotage attempts via cyberattacks. In this thesis, we critically examine the emerging CPS-driven cybersecurity landscape and investigate how process-aware defenses can contribute to the sustainability of highly connected cyber-physical systems by making them less susceptible to crippling cyberattacks. We introduce a novel data-driven model-free methodology for real-time monitoring of physical processes to detect and report suspicious behaviour before damage occurs. We show how our model-free approach is very lightweight, does not require detailed specifications, and is applicable in various CPS environments including IoT systems and networks. We further design, implement, evaluate, and deploy process-aware techniques, study their efficacy and applicability in real-world settings, and address their deployment challenges

Energy Harvesting and Sensor Based Hardware Security Primitives for Cyber-Physical Systems

The last few decades have seen a large proliferation in the prevalence of cyber-physical systems. Although cyber-physical systems can offer numerous advantages to society, their large scale adoption does not come without risks. Internet of Things (IoT) devices can be considered a significant component within cyber-physical systems. They can provide network communication in addition to controlling the various sensors and actuators that exist within the larger cyber-physical system. The adoption of IoT features can also provide attackers with new potential avenues to access and exploit a system\u27s vulnerabilities. Previously, existing systems could more or less be considered a closed system with few potential points of access for attackers. Security was thus not typically a core consideration when these systems were originally designed. The cumulative effect is that these systems are now vulnerable to new security risks without having native security countermeasures that can easily address these vulnerabilities. Even just adding standard security features to these systems is itself not a simple task. The devices that make up these systems tend to have strict resource constraints in the form of power consumption and processing power. In this dissertation, we explore how security devices known as Physically Unclonable Functions (PUFs) could be used to address these concerns. PUFs are a class of circuits that are unique and unclonable due to inherent variations caused by the device manufacturing process. We can take advantage of these PUF properties by using the outputs of PUFs to generate secret keys or pseudonyms that are similarly unique and unclonable. Existing PUF designs are commonly based around transistor level variations in a special purpose integrated circuit (IC). Integrating these designs within a system would still require additional hardware along with system modification to interact with the device. We address these concerns by proposing a novel PUF design methodology for the creation of PUFs whose integration within these systems would minimize the cost of redesigning the system by reducing the need to add additional hardware. This goal is achieved by creating PUF designs from components that may already exist within these systems. A PUF designed from existing components creates the possibility of adding a PUF (and thus security features) to the system without actually adding any additional hardware. This could allow PUFs to become a more attractive security option for integration with resource constrained devices. Our proposed approach specifically targets sensors and energy harvesting devices since they can provide core functions within cyber-physical systems such as power generation and sensing capabilities. These components are known to exhibit variations due to the manufacturing process and could thus be utilized to design a PUF. Our first contribution is the proposal of a novel PUF design methodology based on using components which are already commonly found within cyber-physical systems. The proposed methodology uses eight sensors or energy harvesting devices along with a microcontroller. It is unlikely that single type of sensor or energy harvester will exist in all possible cyber-physical systems. Therefore, it is important to create a range of designs in order to reach a greater portion of cyber-physical systems. The second contribution of this work is the design of a PUF based on piezo sensors. Our third contribution is the design of a PUF that utilizes thermistor temperature sensors. The fourth contribution of this work is a proposed solar cell based PUF design. Furthermore, as a fifth contribution of this dissertation we evaluate a selection of common solar cell materials to establish which type of solar cell would be best suited to the creation of a PUF based on the operating conditions. The viability of the proposed designs is evaluated through testing in terms of reliability and uniformity. In addition, Monte Carlo simulations are performed to evaluate the uniqueness property of the designs. For our final contribution we illustrate the security benefits that can be achieved through the adoption of PUFs by cyber-physical systems. For this purpose we chose to highlight vehicles since they are a very popular example of a cyber-physical system and they face unique security challenges which are not readily solvable by standard solutions. Our contribution is the proposal of a novel controller area network (CAN) security framework that is based on PUFs. The framework does not require any changes to the underlying CAN protocol and also minimizes the amount of additional message passing overhead needed for its operation. The proposed framework is a good example of how the cost associated with implementing such a framework could be further reduced through the adoption of our proposed PUF designs. The end result is a method which could introduce security to an inherently insecure system while also making its integration as seamless as possible by attempting to minimize the need for additional hardware

Efficient Security Protocols for Constrained Devices

During the last decades, more and more devices have been connected to the Internet.Today, there are more devices connected to the Internet than humans.An increasingly more common type of devices are cyber-physical devices.A device that interacts with its environment is called a cyber-physical device.Sensors that measure their environment and actuators that alter the physical environment are both cyber-physical devices.Devices connected to the Internet risk being compromised by threat actors such as hackers.Cyber-physical devices have become a preferred target for threat actors since the consequence of an intrusion disrupting or destroying a cyber-physical system can be severe.Cyber attacks against power and energy infrastructure have caused significant disruptions in recent years.Many cyber-physical devices are categorized as constrained devices.A constrained device is characterized by one or more of the following limitations: limited memory, a less powerful CPU, or a limited communication interface.Many constrained devices are also powered by a battery or energy harvesting, which limits the available energy budget.Devices must be efficient to make the most of the limited resources.Mitigating cyber attacks is a complex task, requiring technical and organizational measures.Constrained cyber-physical devices require efficient security mechanisms to avoid overloading the systems limited resources.In this thesis, we present research on efficient security protocols for constrained cyber-physical devices.We have implemented and evaluated two state-of-the-art protocols, OSCORE and Group OSCORE.These protocols allow end-to-end protection of CoAP messages in the presence of untrusted proxies.Next, we have performed a formal protocol verification of WirelessHART, a protocol for communications in an industrial control systems setting.In our work, we present a novel attack against the protocol.We have developed a novel architecture for industrial control systems utilizing the Digital Twin concept.Using a state synchronization protocol, we propagate state changes between the digital and physical twins.The Digital Twin can then monitor and manage devices.We have also designed a protocol for secure ownership transfer of constrained wireless devices. Our protocol allows the owner of a wireless sensor network to transfer control of the devices to a new owner.With a formal protocol verification, we can guarantee the security of both the old and new owners.Lastly, we have developed an efficient Private Stream Aggregation (PSA) protocol.PSA allows devices to send encrypted measurements to an aggregator.The aggregator can combine the encrypted measurements and calculate the decrypted sum of the measurements.No party will learn the measurement except the device that generated it

Co-design of Security Aware Power System Distribution Architecture as Cyber Physical System

The modern smart grid would involve deep integration between measurement nodes, communication systems, artificial intelligence, power electronics and distributed resources. On one hand, this type of integration can dramatically improve the grid performance and efficiency, but on the other, it can also introduce new types of vulnerabilities to the grid. To obtain the best performance, while minimizing the risk of vulnerabilities, the physical power system must be designed as a security aware system. In this dissertation, an interoperability and communication framework for microgrid control and Cyber Physical system enhancements is designed and implemented taking into account cyber and physical security aspects. The proposed data-centric interoperability layer provides a common data bus and a resilient control network for seamless integration of distributed energy resources. In addition, a synchronized measurement network and advanced metering infrastructure were developed to provide real-time monitoring for active distribution networks. A hybrid hardware/software testbed environment was developed to represent the smart grid as a cyber-physical system through hardware and software in the loop simulation methods. In addition it provides a flexible interface for remote integration and experimentation of attack scenarios. The work in this dissertation utilizes communication technologies to enhance the performance of the DC microgrids and distribution networks by extending the application of the GPS synchronization to the DC Networks. GPS synchronization allows the operation of distributed DC-DC converters as an interleaved converters system. Along with the GPS synchronization, carrier extraction synchronization technique was developed to improve the system’s security and reliability in the case of GPS signal spoofing or jamming. To improve the integration of the microgrid with the utility system, new synchronization and islanding detection algorithms were developed. The developed algorithms overcome the problem of SCADA and PMU based islanding detection methods such as communication failure and frequency stability. In addition, a real-time energy management system with online optimization was developed to manage the energy resources within the microgrid. The security and privacy were also addressed in both the cyber and physical levels. For the physical design, two techniques were developed to address the physical privacy issues by changing the current and electromagnetic signature. For the cyber level, a security mechanism for IEC 61850 GOOSE messages was developed to address the security shortcomings in the standard