OT security, short for operational technology security, is the practice of protecting the systems that control physical equipment and processes. In a manufacturing plant, that means the controllers, sensors, operator screens, and networks that run machines, conveyors, ovens, presses, and packaging lines.
Regular IT security protects data. OT security protects operations. When OT is compromised, the result isn't just a stolen file. It can be a stopped line, damaged equipment, or a safety hazard.
OT in Plain Terms
If information technology (IT) is everything in the front office, operational technology is everything on the plant floor that makes things move. Common examples include:
- PLCs (programmable logic controllers): small industrial computers that control machines.
- HMIs (human-machine interfaces): the touch screens operators use to run equipment.
- SCADA systems: software that monitors and controls processes across a facility.
- Sensors and drives that measure temperature, pressure, speed, or position.
- Engineering workstations used to program and update equipment.
Together, these are often called industrial control systems, or ICS.
IT vs. OT: The Key Differences
| Factor | IT (Office) | OT (Plant Floor) |
|---|---|---|
| Main priority | Protecting data confidentiality | Keeping equipment safe and running |
| Typical lifespan | 3 to 5 years | 10 to 20+ years |
| Updates | Installed frequently, often automatically | Applied carefully, often during planned shutdowns |
| Downtime tolerance | A reboot is usually acceptable | Unplanned restarts can stop production |
| Impact of an attack | Data loss or exposure | Halted lines, damaged equipment, safety risks |
These differences explain why you can't simply apply office security rules to the plant floor. Installing an update on a PLC in the middle of a shift could do more harm than the threat it was meant to stop.
Why OT Security Matters More Now
For years, many OT systems were "air-gapped," meaning they weren't connected to other networks. That's rarely true today. Plants now connect equipment to ERP systems for scheduling, to the cloud for monitoring, and to vendors for remote support.
Those connections bring real benefits. They also open paths that attackers can use to move from an office email account to production equipment.
Core Principles of OT Security
Know what you have
You can't protect devices you don't know about. An asset inventory lists every controller, screen, workstation, and network connection on the floor, along with software versions and who supports them.
Segment the network
Separate the plant network from the office network, and control what passes between them. This approach is a cornerstone of industrial security guidance and limits how far an attacker can travel.
Control remote access
Vendor and employee remote connections should be secured with strong authentication, logged, and turned off when not in use.
Limit who can change equipment
Only authorized people should be able to modify PLC programs or HMI settings. This reduces the risk of both attacks and honest mistakes.
Plan updates around production
OT patching should be tested and scheduled during maintenance windows. When an update isn't possible, use other protections, like isolation, to reduce risk.
Prepare for recovery
Keep current backups of PLC programs, HMI configurations, and engineering files. If a controller fails or is altered, you'll need a known-good version to restore.
These ideas connect closely with zero trust security, which assumes no device or user should be trusted automatically.
Where to Find Trusted Guidance
The National Institute of Standards and Technology publishes NIST SP 800-82, its Guide to Operational Technology Security. It's detailed and technical, but it's the leading U.S. reference for organizations that want to build an OT security program.
Frequently Asked Questions
Is OT security only for large factories?
No. A small machine shop with a few CNC machines and a networked quality station has OT. The scale is smaller, but the principles are the same.
Who should own OT security, IT or operations?
Both. Operations understands the equipment and production impact. IT understands networks and threats. The best results come when they plan together.
Does antivirus work on OT systems?
Sometimes, but not always. Some industrial software doesn't work well with standard antivirus. Always check with the equipment vendor before installing security tools on OT devices.
Getting Started
If you're new to OT security, start with an inventory and a simple network diagram. Those two documents reveal most of the big risks quickly.
Maise Technology supports plants with cybersecurity services that respect production schedules. Learn more about our IT services for manufacturing companies, or Get In Touch with your questions.
