# A Review of Industry 4.0 Manufacturing Process Security Risks
## 2 A Complete Paradigm Shift
### Traditional Approach to Manufacturing Process Security  
The typical manufacturing plant infrastructure consists of two main technological platforms, namely operational technology (OT) and information technology (IT) [8]. OT refers to the combination of hardware and software used to monitor plant processes by means of, e.g., sensors and feedback data streams from plant machinery, in order to control these processes by components such as pumps, valves and actuators. Typical examples of equipment that forms part of OT are supervisory control and data acquisition (SCADA) systems, programmable logic controllers (PLC), measuring equipment and human-machine interfaces. Combinations of these platforms are used to ensure that plant operations run as intended by design, and to prevent hazardous conditions through processes that operate outside the process limitations and safety margins. Figure 1 illustrates the basic concept of the interconnectivity of OT in the typical manufacturing plant:  
It can be seen from Figure 1 that OT platforms are typically connected to a central authority that monitors and controls the manufacturing processes. This can be in the form of multiple PLCs  
Figure 1: A typical operational technology (OT) industrial systems network architecture. and SCADA systems that receive data from sensors and make adjustments to the manufacturing process by means of controlling valves, pumps and actuators, based on the data received from the sensors. Furthermore, many processes rely upon human interaction, ranging from changing equipment settings to manually changing the states of systems through mechanical switches. These actions are to be performed by plant technicians and engineers who are skilled and knowledgeable in the manufacturing processes, and have exclusive access to the associated hardware and software platforms. This immediately points out one of the key vulnerabilities in OT systems security, since the state of the OT systems security is highly dependent on the trustworthiness of the plant technicians and engineers. A significant amount of trust is put into these plant personnel to perform the right manipulations to the OT systems and to perform their activities without any malicious motives at all times. The significance of plant technicians' and engineers' trustworthiness can be appreciated by considering the Maroochy Shire sewage spill incident that occurred in Queensland, Australia in the year 2000 [2]. This incident was allegedly the result of the behavior of a disgruntled contractor whose malicious actions allegedly resulted in the spillage of nearly 1 megaliter of raw sewage into a nearby river. The spill stretched out up to nearly 12 km away from its source. An investigation into the incident revealed that a number of SCADA systems that controlled over 140 sewage pumping stations had been hacked and controlled by means of inducing faults in the SCADA systems through compromised control messages. Communication between the central control center and the pumping stations was facilitated by means of a private two-way radio communication system that operated through a number of repeater stations, as illustrated in Figure 2 below. Because of a lack of proper access control and cyber-security measures of the sewage plant's control systems, it was possible for the ex-employee to easily obtain access to the control systems' network of the plant, particularly given the fact that he had in-depth knowledge of the architecture of the network. The Maroochy Shire sewage spill is a classic example of a security breach within a SCADA system. Historical data of industrial control system (ICS) incidents indicate that such incidents already started occurring as early as 1982 [8]. However, after the introduction of SCADA systems that communicate via transmission control protocol/Internet protocol (TCP/IP) in the early 2000s, the number of ICS incidents increased dramatically.