The emergence of IIoT
Increasingly, many of the above functions are being tied together using industrial/internet of things (IIoT) for monitoring and control. These kinds of systems were built and designed to run in protected environments. While having a safe and reliable function is an important requirement, connection to the Internet was not—at least initially. Legacy OT was almost universally deployed as a closed system that kept attackers out.
2. The need for “Availability”
Another critical driver for OT is emphasis on the “A” part of the CIA (confidentiality, integrity, availability) triad. In a closed system, confidentiality and integrity are easier to maintain, leaving availability as top priority. If your company depends on the assembly line or drilling rig staying operational, availability moves to the forefront on the priority list. This brings with it some trade-offs that may seem odd to those born and raised on the IT side of the house.