Which ones? The technical aspects are all known to be practical. The only thing odd is that a reasonably sophisticated and determined attacker is seemingly targeting him specifically and no one else.
We know that Stuxnet spread beyond it's intended target - that's how it was discovered by the wider security community in the first place. Malware this pernicious could spread fairly stealthily through a large number of people without being noticed I'd imagine.
(If it really is using high frequency audio to leak data then that would be strong evidence that it was originally designed to target some group using air gapped computer networks to protect their high grade information. If your top secret & merely secret grade computers are laptops in the same room & they can communicate over a back channel like this then suddenly your air gapped computer network isn't cut off from the internet any more!)
No, they aren't. Not by a long shot. They sound vaguely similar to some that are however, so people are overlooking the details that would take this from advanced malware to hollywood fantasy.
Strangest of all was the ability of infected machines to transmit small amounts of network data with other infected machines even when their power cords and Ethernet cables were unplugged and their Wi-Fi and Bluetooth cards were removed
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Did you even read the article? It's a laptop. That would be the safe assumption, anyway. Laptops far out-stripped desktop sales years ago, they're what most work happens on now.
> And saying that computers are communicating by speakers and microphones over long distances (i.e. > a few inches) is patently ridiculous.
It's not. I've done it myself. Go grab a couple laptops and some PSK31 software and you can do it, too.
As for communications via speakers and microphones, that makes as much sense as any other outrageously insane theory I've ever heard.
Keep in mind he's talking about laptops that have batteries.