Demonstration of DoS Attacks on Modbus Protocol Using an Experimental CPS Testbed

The traditional power system has evolved into a cyber-physical system (CPS) through smart grid integration. To develop effective detection and defensive strategies against rising threats, a controlled CPS testbed is crucial. This study emphasizes an experimental CPS testbed using commercial devices, with Modbus TCP as the communication backbone. The CPS testbed's physical layer features a three-feeder microgrid built with Lucas-Nuelle training system modules. The cyber layer involves data acquisition using Raspberry Pi 5 devices and control operations handled by a ILPLC from Arduino. Data from the physical layer is locally stored in an InfluxDB time-series database and visualized via chronograf platform. This study demonstrates two denial-of-service attacks on an energy meter using a dedicated attacker agent. The flood attack congests the network by sending a large volume of fake packets to the target, disrupting communication. The resource exhaustion attack, on the other hand, sends multiple read requests to the meter, depleting its computational resources. While both attacks effectively disrupted data acquisition, the resource exhaustion attack was more severe, as it directly strained the meter's resources, preventing it from processing legitimate requests and causing more extensive damage.