An Overview of the Security of Programmable Logic Controllers in Industrial Control Systems

One key role in industrial control systems (ICSs) is known as Programmable Logic Controller (PLC). However, with the development of the Internet of Things (IoT), PLCs have become exposed to an increasing number of attacks, which may cause malfunctions of the whole ICS. Thus, it is necessary to identify potential attacks on PLCs and propose effective solutions to mitigate them. Unfortunately, to date, there have not been significant efforts made to provide a detailed overview of existing works on PLC security. With such a concern in mind, in this paper, we focus on summarising PLC security from different components running at different layers of a PLC architecture. We first review the framework of PLCs; then, we discuss several models when considering PLC security. After that, we provide an overview of existing attacks on PLCs and general solutions to those issues from different perspectives. Lastly, we conclude this paper with an overview of future research areas in PLC security.