The Ordinary Ways OT Environments Actually Get CompromisedThe Ordinary Ways OT Environments Actually Get Compromised

Most OT compromises don't begin with a sophisticated attack. They begin with something ordinary: a USB drive, a remote-access session, a vendor laptop, or an engineering workstation that has quietly picked up software it shouldn't have.

The Pathways We Keep Seeing

Across OT environments, the same pathways keep coming up.

USB and removable media can introduce risk when an unscanned drive is connected to a PLC engineering port.

Remote access becomes a concern when a VPN session appears outside the normal maintenance window or from an unexpected location.

IT-to-OT movement is worth investigating when enterprise traffic reaches Level 1 or Level 2 devices without passing through a defined conduit.

The Less Obvious Ones

Then there are the pathways that are easier to miss.

An engineering workstation with unexpected software or unusual processes can become a route into PLC programming functions. Vendor access can create exposure when a connection wasn't scheduled or a firmware change happens outside the documented process. And with legacy protocols, unexpected Modbus or EtherNet/IP traffic from outside the expected control network should raise a question.

What These Pathways Have in Common

None of these scenarios requires a highly sophisticated attacker. They require access, opportunity, and patience.

The harder part is knowing what to look for before something goes wrong — which is what we tried to make practical in Chapter 3 of the OT Cybersecurity Field Guide: the realistic threat scenario, what you can actually observe, and what you can do about it.

If you'd like a copy of the guide, get in touch and we'll send it over.