Live data from Hacker News

AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

blog.laserphile.com

121–130 of 348 posts

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#122
post #96

Earlier quoted context omitted.

Not sure if they still do, but a couple years ago prices in the app were lower than on the website. And they promoted installing it to save money.

And someone would install random apps to save $5 on $100 purchases?

When I did customer tech support for a major retailer, we had confused customers calling all the time because they would randomly get price-match refunds they never asked for. They were installing apps that were automatically requesting the refunds by searching their emails for orders and checking the prices on the websites. These people had no idea they had even given these apps permission to read their emails.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#124
post #17
post #13

Just curious, why silent sound would allow fingerprinting? What are they sampling if it can't be heard?

The script generates a known waveform, it is passed through the browser's audio implementation and then the script analyses the result after. Based on your devices settings and hardware the output will be different, e.g. a PC with analog output might have 44KHz audio output bandwidth, but a bluetooth headset might have a lower, different audio bandwidth. That is a datapoint that can be used in device fingerprinting a…

On the one hand, I wouldn't expect too many variations here (the vast majority of devices probably use 48 kHz and 24-bit output, a few use 44.1 kHz and/or 16-bit, etc.) but just like DPR and all the other properties with a very small set of popular values in practice, you only need a bit or two from each measurement to eventually have a high quality fingerprint.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#125

Earlier quoted context omitted.

Not sure if they still do, but a couple years ago prices in the app were lower than on the website. And they promoted installing it to save money.

I believe the prices are the same. But the app has a number of "games" to collect tokens that get credited as discounts. Seems to be mostly stuff designed to get you to open the app daily and browse their offers. Which might be "innocent" if it's just to get you to buy more stuff, or maybe they have more reasons they want you to have the app open. Who knows At least Aliexpress doesn't have all the fake slot machine t…

There are few things more scammy than AliExpress “discounts”. I have yet to see a cent of the hundreds of dollars of “savings” they gave or advertised to me.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#126
post #33

Earlier quoted context omitted.

Where is "we"?

Likely the place where people are "willing to trade privacy for convenience", according to Baidu's CEO.

I always wonder if it's worth it. Like: is it actually convenient, or is it 'solving' inconveniences which actually do not exist or didn't exist before using the service? I have never used Prime or AliExpress but also don't consider our typical shopping very inconvenient. And the most inconvenient parts are actually the ones which seem necessary to to get the proper goods (from past weeks: vegetables/fruits/shoes - it's not really possible to order that online and get exactly what we want). And everything else is available from other webshops.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#127
post #91

Earlier quoted context omitted.

It's the website. The title of the article literally mentions "WebAudio", and the first paragraph states that the author is using a PC. The second paragraph mentions Chrome and Firefox. Apple and the App Store have zero involvement here.

This is a huge stretch, but if this problem exists in not only the PC versions of Chrome/Firefox but also the Android/iOS versions, then theoretically the app store reviewers could flag the browsers for facilitating this behavior against app store guidelines. In practice, apps of such caliber as popular browsers might be a bit above such reviewers' pay grade, so to speak.

> This is a huge stretch

This is nonsense. Safari also supports Web Audio. Safari does not, however, support Microsoft Windows, which is why the article author didn't mention it.

Moreover, all web browsers on iOS have to use Apple WebKit, so Web Audio support is not actually the fault of the non-Apple browser vendors.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#128
post #52

Cloudflare challenges also use Web Audio, by the way.

Does it hold an audio stream open constantly or just briefly during the challenge? On AE it never stops

Just briefly during the challenge.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#129
Aha this would explain. I have seen similar behaviour with a news website trying DRM requests (has no reason to ask this info) resulting in stopping playback.. did not consider the impact of multipoint here. Interesting, might be worth looking into if i see this "bug" again.

Re: AliExpress runs silent WebAudio fingerprinting that breaks Bluetooth multipoint

#130
post #9
post #8

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.

I cannot ever imagine installing something like AliExpress as an app.

Absolutely crazy the amount of dodgy apps people install and giving permissions to read the system when asked...
Post reply on HN