AliExpress Accused of Fingerprinting Users via Inaudible Sounds

Chinese retailer AliExpress has been accused of fingerprinting visitors using inaudible sounds, which affected a researcher's ability to use his Bluetooth headphones. Researcher Matthew Callaghan reported that when he loaded the AliExpress homepage, audio from his phone ceased to play through his multipoint headphones, which can connect to multiple devices simultaneously. He discovered that the issue occurred each time he accessed the site and resolved when he closed the tab. Upon further investigation, Callaghan identified two obfuscated scripts that created a graph analyzing WebAudio readings from visiting browsers. This graph functioned as an oscillator measuring Sawtooth waves, which are typical in digital audio output.