Modbus

We also discussed machine safety systems and also claims made by certain people about cybersecurity and industrial safety.

In this episode, we will look at PLC networking together with a detailed look at one network protocol, Modbus.

Types of Networks PLC networks fall into three broad categories based on the purpose of the network.

These categories are PLC to I.O., PLC to PLC, and PLC to PC or personal computers.

That requires a data protocol.

Each manufacturer tended to come up with their own protocol.

Modicon developed Modbus, Allen Bradley came up with DF1, Siemens created 3964R and RK512.

Other manufacturers generally each had their own.

But we could see even then in the late 90s that as computers were going to become more popular, vendors were already playing with the idea.

Modbus had not been invented yet, but it was being talked about, is how do we get this signaling stuff, plus minus five volts or a change in air pressure or, you know, color changes.

How do we get that down to a packet? that I can just move along with email and voice on a common infrastructure known as an Ethernet or a fiber ring, you know, these kind of, and we could see the train wreck coming, those of us in the security world, because we already knew about bad actors.

You know, go back to what I was talking about earlier, where we learn how to gain access to stuff you're not supposed to have access to.

Now you can say, what does good look like? And we were talking earlier in the week about the IDS stuff.

And people say, well, you recorded it and says, why does IDS matter? And the reason IDS matters now is because there are certain situations, let's take Modbus, where somebody should be able to do a Modbus read, but not a write.

If you encrypt that traffic end to end, how are you ever going to see that? And no other platform is going to pick that up.

And that's why, as one of the things that I'm working on in Chasm, I can bring up an SSH workspace, and you're right in that workspace with key logging and things, as opposed to on your laptop where you're connected in, and now you just come through and you go to the box and you do SU root, and you can go anywhere you want.

And CISOs are a short game, right? Average tenure of a CISO is 26 months, less than three years, right? So you got a dozen, 15, 20, 30, 40, 100 plants, and you think you're going to be able to architect and roll out a cybersecurity strategy and solution sets for those facilities in a very short period of time? You're kidding yourself.

Yeah, and it's funny you mentioned that, Dino, because we've had the screens to show temperature collection out of the lab we've built now for over eight months, almost a year.

And it took us less than, what, half an hour to get it funding into Elasticsearch, a couple MQTT commands, some Modbus work.

The device already has it built in, and all I had to do was build a little widget on the screen that says, show me temperature.

Yeah, Alan Bradley, Unitronics, you might see the odd Schneider or Siemens one.

Like, I mean, and then if you're going down that road, then you've got Modbus, you've got all these things.

Like, if you say Modbus to an apprentice

that's ever come over this time, he'd say, what are you talking about?

Yeah, yeah.

mean, if you take the electrical curriculum and say, divide it up into sections, there's surely 20, 30% of your electricians that you're training are working in a factory environment.

Straight away, you're into 4 to 20 milliamps PLCs.

You're into Modbus.

So let's keep going.

that as well um any other ideas yeah i don't want to um try using the modbus protocol so we might be able we can try that uh Let's actually try the Modbus protocol attempt that you wrote above.

In fact, is that this one right here? Yeah.

So we can accept that.

Did it have Modbus test? The Modbus underscore test.py.

I should already have that.

Yeah.

Okay.