Cybersecurity
PLC Security
Protecting the device that moves the equipment.
Written guides in this section
Full references, procedures, and diagnostic guides published under PLC Security.
Controller Hardening
What can be locked down on a PLC or RTU: keyswitch and mode, credentials, unused services, access lists, firmware, and the engineering workstation that is the real target.
12 min readUpdated Sep 5, 2026
Controller Mode Switch and Keyswitch
The physical switch on the front of a controller: what RUN, REMOTE, and PROGRAM mean, why most controllers are left in REMOTE and why that matters, a policy for a utility, how mode is monitored and alarmed, and what to do on platforms with no keyswitch.
8 min readUpdated Sep 5, 2026
Firmware Management
Updating the firmware of controllers, modules, drives, HMIs, switches, and radios without breaking the plant: why firmware lags and why it still matters, tracking versions, deciding what to update and when, and the update as a planned outage with a rollback.
9 min readUpdated Sep 5, 2026
Controller Program Integrity
Knowing that the program in the controller is the one that was approved: checksums and change counters, the scheduled compare against the trusted backup, signed and protected projects, what an unexplained difference means, and making the check routine.
8 min readUpdated Sep 5, 2026
Disabling Unused Services
Every service a device runs is a way in, and most ship with more running than the plant uses: web servers, file transfer, shells, discovery, management protocols, unused ports. Finding what is listening, deciding what the plant needs, and turning off the rest.
8 min readUpdated Sep 5, 2026
Topics in this area
Controller Hardening
Controller Hardening — practical reference notes for controls engineers, integrators, and technicians working with plc security.
Mode Switch And Keyswitch
Mode Switch And Keyswitch — practical reference notes for controls engineers, integrators, and technicians working with plc security.
Firmware Management
Firmware Management — practical reference notes for controls engineers, integrators, and technicians working with plc security.
Program Integrity
Program Integrity — practical reference notes for controls engineers, integrators, and technicians working with plc security.
Disabling Unused Services
Disabling Unused Services — practical reference notes for controls engineers, integrators, and technicians working with plc security.
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