(arxiv.org)
The famous air gap case is stuxnet, but there are other technical and biological approaches.
It’s a very weird reality we’ve found ourselves in if you stop, zoom out about, and really take in the gravity of the issues we are grappling with as a human race. Exciting, truly, and a bit nerve wracking.
We are a long way from AI agents escaping air-gapped computers, let's worry about that when it's an actual problem and when the companies running thousands of agents are acting responsibly.
Set the right incentives at the top, and you will soon see that changes are made very quickly ... especially those 'industry leaders' previously called 'impossible to contain' or 'non-competitive' BS.
If everyone has to play by the same rules, and the rules are made for the good of society, then there is a true win-win - and not just a wealth transfer to the top and putting expensive damages on the general population.
Can’t leak secrets if you don’t have RAM.
I'm wondering if anything ends up back there thru the PSU during normal use of a computer, or if the high frequency components get filtered out.
(Though maybe secure computers do things differently with the power as well?)
I wonder if even "just" throttling up/down the CPU / GPU on tasks as morse code might be visible externally to other devices on the same mains supply. Obviously it would be very inefficient speed-wise, but a higher current (say + 300 watts for the GPU being used) should result in a slightly lower voltage on the mains supply I think for the duration?
Obviously things like PSUs could (I'm not an expert at any of this) get in the way of this, and I'd assume in data centres there's some isolation between different racks.
But for a scenario of DIY "airgapping" two machines in an office for AI testing (i.e. not doing it very well), it might be a plausible way of AIs finding to communicate if there's no actual network connection.
Obviously other electronic devices connected to the same mains circuit could also be adding their own noise, which might make it a lot harder to actually identify and decode the response, but... if ML/AI agents are good at anything, it's finding patterns, so I wouldn't want to bet against it being theoretically possible...
brb reviewing some EE material...
But don't expect much from me... I wanted to do a final year project in Power Line Communication for my electrical engineering undergrad. Then-me decided it was a dead end... cannot go WAN-scale; too much line noise and signal transmission power loss. I did something else with power electronics---I can't remember---but then again, my undergrad was also a dead end :p
Still, I'd guess that the odds of remote exploits are better if one wants to control a device via the PSU-as-backdoor, versus exfil data from it. Do like the IoT people and UDP broadcast naughty control signals to the power circuit / subsystem that has the compromised device.
Guessing further, remote exfil will mean having a close-proximity wiretap into the precise power line circuit of the target infra---because of signal losses---it could still be UDP broadcast exfil. Or a physical tap at whatever power transformer is the single point of connect between the target and the main grid. And if you can't get anywhere near the installation, well you can't exfil, because AFAIK it's pretty hard to reverse a signal up a transformer back into the main grid.
A scan of the arxiv paper appears to suggest similarly---the situation they describe presumes a wiretap into the circuit or the mains switchboard.
Paraphrasing:
The only way to secure a computer is to not buy one. And if you buy one, to never plug it in. And if you plug it in, to never switch it on.
Something like the cheapest way to own $GasGuzzlerWithItsOwnPinCode is to bring it home after purchase, and set fire to it in the yard.
Some of the sites I look after at work still have modems attached to the incoming electricity meter from a Broadband-over-Power-Line trial about 15 years ago. It wasn't very fast - it was supposed to be 200Mbps but struggled to do 20, and was often more like 2Mbps - and it radiated RF hash everywhere powerlines ran, from about 500kHz to well up into the hundreds of MHz. What eventually killed it in NE Scotland here was it splattered all over marine VHF, in an area with lots of marine traffic like oil platform supply vessels.
TL;DR anything that uses basically RF over unshielded untwisted cables that radiate everywhere is inefficient and antisocial.
Still available today, and has worked well for me when I've needed it.
Back in the day with crt screens you could just capture the frequencies transmitted when creating the picture and look at the copy straight away.
No malware. No direct contact. And it worked over rather big distances.
No matter how well you argue that it is "perfectly secure", when some nerd outside the polling station is showing reporters a real-time feed of who people are voting for, your machine will get thrown out.
It wasn't quite CRT-level of mirroring, but it wasn't far off...
This way, if malware gets installed on your router, doing a cold boot will eliminate it. You can have a timer to just cold boot it regularly.
I've suggested this many times. The rationale for not doing it is so the firmware can be remotely updated. Well, that's exactly how malware infects it.
Coming from a non-EE background, this is the most interesting part to me. 10ms is an eternity in programming perf work, but it's already very constrained in how clear the signal is for reading the transmission. I just find it interesting that we want to do nothing to create a signal. Perhaps this makes it harder to exploit?
It's much easier to subvert the supply chain for the secure hardware or subvert the authorised system transfers.
Of course, now you've got a Tesla coil in your data centre, which will bring you a whole new set of Interesting Problems to cope with.
With a suitably tightly focused telescope you could pick up the LED blinking and decode the data going over the port.
It's not even a contest anymore, that man is the heavyweight champ of air-gap security.
Right… I’m going to stop reading after these words. With malware on the computer you can change the heat signature of the room of you’re bored enough. https://xkcd.com/1172/
After that, I set the computer on a metal plate to keep a fire from spreading to the floor.
Some years later, the PSU went out with a bang and a lot of smoke.
(dmd is so fast, the computer doesn't have time to heat up!)