Students escalate into full man-in-the-middle attacks on OT networks. The instructor demonstrates designing a device with relays and MAX485 modules that intercepts all traffic between PLCs and clients. Unlike simple sniffers, this device can modify, inject, or block packets in real time. Emphasis is placed on timing challenges, avoiding collisions, and synchronizing injection with GPIO controls. This class connects to the module by moving students from passive observers to active manipulators of OT processes.

Learning Objective
Build and operate a man-in-the-middle device for OT exploitation.

Training Outcomes

• Understand MITM hardware design.

• Control direction of RS485 communication.

• Modify and relay traffic safely.

Hands-On Experience

• Assemble MITM devices with relays.

• Intercept and alter live traffic.

• Test MITM on PLC-client communication.