Today, the once sacred boundaries between IT and OT networks are becoming more and more blurred. As one of the most important links in industrial control and industrial control networks, PLCs are increasingly connected to their industrial control systems or other PLCs. device of. So, how can we protect our PLC system from foreign invasion? Check out these 20 tricks below! (The code in the text takes Rockwell PLC as an example)

Proper programming of the PLC is the best defense.Industrial security practice guidelines for PLCs typically include the integrity, hardening, resiliency, and monitoring of PLCs in industrial networks. These tricks below refer to Rockwell Allen-Bradley’s RSLogix5000 task monitoring tool, which includes the ability to baseline their PLC’s memory usage and track any trends, and is really more about preventing misconfigurations from causing physical events, as operators and technology Human error is the leading cause of network outages in industrial systems. For example, recommendations to monitor PLC memory could flag any unusual activity, as PLCs tend to use memory at consistent levels over time. This is useful if you suddenly see a spike in memory usage and are concerned about it.

Modular PLC code

Monitor operating mode

Keep the operating logic in the PLC as much as possible

Use PLC flags as a sanity check

Use encryption and/or checksum integrity checks on PLC code

Verify timers and counters

Validate and remind paired input/output

Validate HMI input variables at the PLC level, not just at the HMI

Verify Indirect Addressing

Assign specified register blocks by function (read/write/verify)

Credibility Check Tool

Validate input against physical plausibility

Disable unwanted/unused communication ports and protocols

Limit third-party data interfaces

Define the safe process state when the PLC restarts

Summarize PLC cycle times and trend them on HMI

Log PLC uptime and trend it on HMI

Log PLC hard stops and trends on HMI

Monitor PLC memory usage and trend it on HMI

Capture false negatives for critical alerts

Editor: Huang Fei

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