Secure Industrial Automation Using Protocol Packet Inspection and Blocking to Safeguard Process Industry

National Critical Infrastructure (NCI) are those systems, assets which are essential for a country to function. The safety of critical infrastructure systems has recently become a most important concern for many nations. Industrial Control Systems (ICS) or Cyber Physical Systems (CPS) are deployed in NCI for automation of various industrial processes. Security of ICS/CPS systems is very crucial for uninterrupted services of NCI sectors. Communication protocol security is one of the pivotal areas in security of these systems. Modbus is mostly widely used communication protocol in SCADA system, which is one of the main systems used in ICS processes. Modbus protocol was developed without considering security and more vulnerable to cyber-attacks. In this work, Man-in-the-Middle cyber-attacks like false response injection, false command injection and Denial-of-Service (DoS) attacks, on Modbus protocol, were explained. Next, a new methodology called MODBUS Fame Inspection & blocking Module (MBFIBM), for protecting Modbus protocol in SCADA system, was designed and implemented. This module filters malicious traffic by inspecting various features of the incoming Modbus frame with configured parameters and allows only eligible Modbus request to reach PLC. This module protects Modbus protocol based SCADA systems from these cyber-attacks. Hence, it will secure process industry with Industrial Control Systems or Cyber Physical Systems to safe guard National Critical infrastructure.