Rockwell Automation offers these common rationalizations plant floor managers use to avoid confronting security concerns:
As long as the firewall is OK, we’re OK on the plant floor.
IT has security figured out and will take care of it for me.
There are no new security issues as the plant level.
If there really are new issues, I’m sunk until new standards and technologies rescue me.
Because nobody knows about my plant floor network, I have “security by obscurity.”