This basically describes the Iranian nuclear system that was hit by stuxnet, which, as I recall, was spread via USB drive.

The airgap certainly reduces the chances of getting hit with a joe-random ransomware attack, though. Defense in depth...

This is what the financial industry does. There's a secured "extranet" that everyone runs FIX on top of. For the most part, it works.

> You could have an air-gapped system and still have remote access

You're suggesting the gas company run their own network, and then you assume no employee will connect that network to the general internet for their own convenience? Not happening.

Before the 90s? Hmm. Well, if you believe Thomas C. Reed's account, the US was using trojans to sabotage Soviet oil pipelines in 1982.

Sounds looks a solved problem, but it isn’t. The electrical grid isolates SCADA networks from the internet, so substations are interconnected via dedicated networks. But then at the command centers you have the entire monitoring and control systems with on site operators. Then, inevitably you will have some employees with vpn access, and now you have 2 vectors: remote admins getting hacked and local admins plugging in external devices. You’d think it’s easy to get rid of vpns, but things like the pandemic brought them all back to full force.

Is this even safe enough, though? They had one of those in the Iranian uranium enrichment facilities, and it still didn't work out for them.

Is the argument that Iran was attacked on air-gapped network, so its not worth doing?