Great. Now Even Your Headphones Can Spy on You

Realtek drivers on Linux, at least for some codecs, have this feature built-in, no malware needed. On my Dell XPS 13 9350, for example, I can use alsamixer or pavucontrol to choose between "Internal Mic," "Headset Mic," and "Headphone Mic."

The "Headphone Mic" setting is designed for connecting a microphone to the single multi-purpose 3.5mm jack, but it can also record audio from a pair of headphones just fine if you turn the gain up.

Huh.

I remember back in the old days of the internets back when a cable modem meant you were bougie.

When we were playing tetrinet, some people didn't have mics but somehow hacked a set of headphones to work as a mic. I remember the audio quality wasn't -great- but what was back then?

I'd guess at least some of this is based on hacking the audio drivers that let the ports be 'controlled', i.e. how on some desktops when you plug a speaker in it asks whether you plugged in a speaker or a mic.

> Their malware uses a little-known feature of RealTek audio codec chips to silently "retask" the computer's output channel as an input channel, allowing the malware to record audio even when the headphones remain connected into an output-only jack and don't even have a microphone channel on their plug.

This is a pretty big deal.