Prototyping PLCs and IoT Devices in an HVAC Virtual Testbed to Study Impacts of Cyberattacks

Abstract

This work describes a virtual testbed of a heating, ventilation, and air conditioning (HVAC) system that has been developed. The testbed incorporates a programmable logic controller (PLC) and is applicable to Internet of Things (IoT) devices. The PLC’s ladder logic program uses hysteresis control and multiple modes of operation. This form of control was selected because of its common use in industry and even in residential applications. The purpose of this work is to demonstrate that by using modern tools and platforms, such as OpenPLC, a controller for an HVAC system can be prototyped and used to research and explore possible cyberattacks and their effects in various cyberphysical systems. In particular, possible and plausible implementations of the aforementioned hysteresis controller in ladder logic are studied and described to the reader. Also, in the experimental results, this work explores how these implementations can be compromised by an injection attack to change settings and by a malicious ladder logic upload in the virtual testbed. The impacts of cyberattacks in terms of safety and cost are discussed also.