OpenPLC: An IEC 61,131-3 compliant open source industrial controller for cyber security research

The last decade has seen multiple instances of cyber-attacks that have been successful in sabotaging the normal operation of SCADA systems and PLCs. To counter these attacks, researchers have put their efforts in finding defense mechanisms that can protect the network and the PLC. However, since vendors don't make available information about the hardware and firmware of their devices, it becomes challenging to perform cyber security research for PLCs. This work proposes the development of an open source PLC, compliant with the IEC 61,131-3 international standard. A description of the hardware architecture, development environment, supported SCADA protocols and an additional HMI editor package is presented. Additionally, this work presents a methodology for validating PLC logic execution, performance, and SCADA connectivity, and also compares the behavior of OpenPLC with four other popular commercial PLCs when under a Modbus injection attack, to support the claim that OpenPLC is a valid platform for PLC cyber security research.