My takeaway is: if an air-gapped system is compromised, just assume all data on it is at high risk of exfiltration.
I won't be surprised if even the power connection becomes a future (unintended) means of data transmission.
I won't be surprised if even the power connection becomes a future (unintended) means of data transmission.
That's already a thing. From the same author as the TFA, PowerHammer [1] exfiltrates data using current flow fluctuations. There's also Powermitter [2] (from some researchers at Wuhan University), which is exfiltration via power supply EMF leakage.
[1] https://arxiv.org/pdf/1804.04014.pdf - by the same guy as the OP paper