To reduce the risk of unauthorized devices being plugged into HMIs and panel PCs on the plant floor, which physical hardening measure is most directly relevant?
- A.Increase the HMI's display brightness to deter shoulder-surfing
- B.Disable or physically block unused USB and network ports and lock enclosure doors so cabling and ports are not casually accessible
- C.Replace copper Ethernet with longer patch cables for flexibility
- D.Label every port with its IP address for faster troubleshooting
Why B is correct
Physical port security disables, fills, or locks unused USB and network ports and restricts physical access to enclosures. This prevents an insider or visitor from quietly attaching a rogue device, which logical controls alone cannot stop once someone has hands-on access.
Know someone studying for OT Security Fundamentals? Send them this one.