Modbus/TCP
Modbus/TCP is the TCP/IP version of Modbus, a decades-old industrial communication protocol used to read and write values -- sensor readings, relay states, setpoints -- on programmable logic controllers (PLCs) and other industrial equipment, typically over port 502. It was designed in an era when industrial networks were assumed to be physically isolated, so the protocol itself has no authentication, authorization, or encryption built in: whoever can reach a Modbus/TCP device on the network can read its registers and, in many configurations, write to them too. Modern industrial networks are increasingly connected to the broader internet, directly or via misconfigured firewalls, which exposes this decades-old assumption as a real risk rather than a theoretical one.
By AdminKit team, Netbase JSC · Updated