I have the schneider unity PLC programming software and was able to connect to about 12 out of 16 of the PLCs I tried that were shown on censys. of the ones I could connect to, two had 'security' enabled so that I couldn't see the program, but still could have stopped it from running or downloaded an entirely new program. 6 PLCs didn't have the program stored in them, so same situation. 4 PLCs I was able to download the program. One was a hydro electric power plant, one was some kind of food factory that used barley, and two were some kind of pumping stations, one of which had a bunch of logic for controlling pH and chlorine. The last modified date for all the programs was in the last 3 years.

None of the programs had any contact information for the programmer or the company that owned the infrastructure.

It is hard to believe people are still putting their plants straight on the internet. Anyone can control any of the outputs which then control real equipment like 200 kV circuit breakers and disconnects, turbines, valves, conveyors, mixers, pumps, etc. If interlocks are implemented in the software as opposed to electrically or mechanically then they can be bypassed which could easily result in equipment damage, injury to personnel, or death.