Cyber-security of Cyber-Physical Systems (CPS)

Abstract

This master's thesis reports on security of a Cyber-Physical System (CPS) in the department of industrial engineering at UiT campus Narvik. The CPS targets connecting distinctive robots in the laboratory in the department of industrial engineering. The ultimate objective of the department is to propose such a system for the industry. The thesis focuses on the network architecture of the CPS and the availability principle of security. This report states three research questions that are aimed to be answered. The questions are: what a secure CPS architecture for the purpose of the existing system is, how far the current state of system is from the defined secure architecture, and how to reach the proposed architecture. Among the three question, the first questions has absorbed the most attention of this project. The reason is that a secure and robust architecture would provide a touchstone that makes answering the second and third questions easier. In order to answer the questions, Cisco SAFE for IoT threat defense for manufacturing approach is chosen. The architectural approach of Cisco SAFE for IoT, with similarities to the Cisco SAFE for secure campus networks, provides a secure network architecture based on business flows/use cases and defining related security capabilities. This approach supplies examples of scenarios, business flows, and security capabilities that encouraged selecting it. It should be noted that Cisco suggests its proprietary technologies for security capabilities. According to the need of the project owners and the fact that allocating funds are not favorable for them, all the suggested security capabilities are intended to be open-source, replacing the costly Cisco-proprietary suggestions. Utilizing the approach and the computer networking fundamentals resulted in the proposed secure network architecture. The proposed architecture is used as a touchstone to evaluate the existing state of the CPS in the department of industrial engineering. Following that, the required security measures are presented to approach the system to the proposed architecture.

Attempting to apply the method of Cisco SAFE, the identities using the system and their specific activities are presented as the business flow. Based on the defined business flow, the required security capabilities are selected. Finally, utilizing the provided examples of Cisco SAFE documentations, a complete network architecture is generated. The architecture consists of five zones that include the main components, security capabilities, and networking devices (such as switches and access points). Investigating the current state of the CPS and evaluating it by the proposed architecture and the computer networking fundamentals, helped identifying six important shortcomings. Developing on the noted shortcomings, and identification of open-source alternatives for the Cisco-proprietary technologies, nine security measures are proposed. The goal is to perform all the security measures. Thus, the implementations and solutions for each security measure is noted at the end of the presented results.

The security measures that require purchasing a device were not considered in this project. The reasons for this decision are the time-consuming process of selecting an option among different alternatives, and the prior need for grasping the features of the network with the proposed security capabilities; features such as amount and type of traffic inside the network, and possible incidents detected using an Intrusion Detection Prevention System.

The attempts to construct a secure cyber-physical system is an everlasting procedure. New threats, best practices, guidelines, and standards are introduced on a daily basis. Moreover, business needs could vary from time to time. Therefore, the selected security life-cycle is required and encouraged to be used in order to supply a robust lasting cyber-physical system.