alt Hacker NewsAliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint
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I noticed in the last few weeks that if I’d recently opened the AliExpress iOS app (ie. it was backgrounded) my car audio would freak out thinking I was giving it an audio command. Killing the AliExpress app immediately fixed the problem. After seeing it happen more than once I assumed it was something dodgey and uninstalled the app.
Recently I ran into a problem with my Bluetooth headphones. They support multipoint bluetooth audio, so they can be connected to my PC and phone at the same time. Opening the Aliexpress webpage causes a silent audio stream keeping the PC>headphone link active blocking my phone audio. An investigation reveals obfuscated code running device fingerprinting with a side effect being a silent audio stream that firefox, chrome and windows does not recognise but which kept the bluetooth connection active.
I've seen this on many many other sites as well, most notably Twitter, and lots of common modern captcha pages too. Very annoying!
They have been doing this for months.
No sound playing but the audio would change like the microphone was being activated. I checked permissions to make sure there was no mic access and figured that they were fingerprinting.
Concerning situation, I think. And I suspect (perhaps wrongly) that there are even more reasons for concern with technology that can track, capture, leak etc. information that's more sensitive or valuable, depending on how one wishes to look at it. Mobile phones, computers, routers etc. -- all have the potential to siphon out valuable information to a bad actor, especially when it comes to espionage, military, commercial etc. This has already happened at a significant scael, so it's not a remote scenario.
At the very least, governments and institutions should develop a framework to investigate all acquired technology. The community / civil society could also create something similar, a script that would analyse at a deep level everything that can be analysed with a piece of software even by a complete novice.
Just curious, why silent sound would allow fingerprinting? What are they sampling if it can't be heard?
Browser fingerprinting can get creative at times, to say the least. eBay's WebSocket port scanner [1] and Reddit's abuse of DRM and JavaScript JIT exploits [2] from years ago are two examples of the kind of in-depth introspection you can perform completely in the background using nothing more than simple non-permission-gated APIs.
OP please submit the filter to an upstream uBlock filter list.
i'd argue that perhaps the ability to play audio should be permission gated, much like the ability to use webcam/microphone.
However, I'd bet that many people will gladly allow aliexpress to play audio as there are probably videos on the site that people want to play and listen to.
With that said, its possible that this can be only a use once permission. Even if I want to shop at aliexpress if I know they are doing this, I'll be more willing to be bothered every time I want to play a video with audio to approve it if this bothers me.