  The smart-grid introduces several new data-gathering, communication, and
information-sharing capabilities into the electrical system, as well as
additional privacy threats, vulnerabilities, and cyber-attacks. In this study,
Modbus is regarded as one of the most prevalent interfaces for control systems
in power plants. Modern control interfaces are vulnerable to cyber-attacks,
posing a risk to the entire energy infrastructure. In order to strengthen
resistance to cyber-attacks, this study introduces a test bed for
cyber-physical systems that operate in real-time. To investigate the network
vulnerabilities of smart power grids, Modbus protocol has been examined
combining a real-time power system simulator with a communication system
simulator and the effects of the system presented and analyzed. The goal is to
detect the vulnerability in Modbus protocol and perform the Man-in-the-middle
attack with its impact on the system. This proposed testbed can be evaluated as
a research model for vulnerability assessment as well as a tool for evaluating
cyber-attacks and enquire into any detection mechanism for safeguarding and
defending smart grid systems from a variety of cyberattacks. We present here
the preliminary findings on using the testbed to identify a particular MiTM
attack and the effects on system performance. Finally, we suggest a cyber
security strategy as a solution to address such network vulnerabilities and
deploy appropriate countermeasures.
