Without a source to corroborate, the tinfoil hat factor is extremely high with this one

I slightly agree. However, these days it seems more and more that "thing elite spy agency does to track terrorist" is on about a 6 months to 1 year lead on "thing startup does to target ads."

Wouldn’t even surprise me if it was the other way around either.

Some of the brightest minds of this generation are working on ad tech.

Sadly.

Angelheaded hipsters burning for the ancient heavenly connection to the starry dynamo in the machinery of night, indeed.

Interesting thanks

Sorry here is the source:

https://www.bleepingcomputer.com/news/security/ultrasound-tr...

It appears to have happened already

Wow, now 44.1kHz sound cards should be very desirable

> A team of researchers from the Brunswick Technical University in Germany discovered [234] Android apps that employ ultrasonic tracking beacons to track users and their nearby environment.

https://en.wikipedia.org/wiki/SilverPush

My tinfoil hat is spinning!

Ability and motive...

Are they able to do this? Yes, for sure.

Are they willing to this? For terrorists or maffia bosses, no doubt. For smaller fish? Maybe they can't be bothered. Or maybe they can.

Once it's productized, it's probably easy to reuse.

Technically, but maybe not bureaucratically.

Here is a source, but no „malware“ but ads, the line gets more and more blurry

https://arstechnica.com/tech-policy/2015/11/beware-of-ads-th...

I'm surprised a computer speaker has the frequency response to play an inaudible tone.

Tested my kids - they could hear an alleged 21khz tone out of laptop speakers. The actual level of the tone doesn't matter - it was above my level of hearing. Wasn't a double blind, but they told me when it started and stopped based on a bash script with random intervals.

I'm 20 but I can still hear 20 khz, albeit not very well.

I could when I was 20, did a proper hearing test when I joined my company. 15.625khz was very noticeable - I scoffed at the old timers who couldn't hear it.

I can no longer hear it. Still I can hear 1khz, so that's what's important.

Most wouldn’t, I’d imagine OP is referring to a mobile device, look at Androids dev docs they recommend sticking to 44.1khz, which we know does fail into the range of human hearing with its 22khz reproduction, albeit fewer people. I’d suspect the person being spied on would become suspicious upon many children they encounter and even more dogs fleeing from their direction.

If they were able to gain access to a person's microphone doesn't that mean they are already compromised?

> TOR or VPN can stop this.

You're saying that the persons of interest in this case were identified and targeted only based on an IP address and not based on some other aspect of their online activity?

Wasn't this how they caught the Silk Road guy? Ross Ulbricht? They played a loud noise from his computer in a public area, as I recall.

that is not how they caught him. They used a correlation attack. He was stupid and posted something using his personal email on stackoverflow about setting up tor website and processing bitcoin transactions. He then used a linked account to advertise silk road a few times. This made him a prime suspect. They followed him for weeks and watched that every time dread pirate roberts logged in and posted on silk road he was sitting in a cafe or library on his computer connected to a vpn. This was enough for them to get a search warrant and they found all the other evidence they needed to convict him on his laptop

Do you have a source for that? I've never heard it before.

Nevermind, they chatted with him, but that was to ensure that he was logged in to SR before grabbing his laptop in an unencrypted state, not to identify him: https://www.wired.co/2015/01/silk-road-trial-undercover-dhs-...

> That malware played a higher pitch sound than can be heard by the human ear.

That should be "... can not be heard ..." right?

Also, do you have a link with more details.

No, it's right as-is.

Ah I think I read the "higher" as "high" and misunderstood it.

That still doesn't really make sense. I think you misread "than" as "that".

"a higher sound than can be heard" or "played a sound, which cannot be heard due to its pitch"

would both work, but your interpretation isn't correct.