China's AliExpress caught using an ‘audio fingerprint’ trick to track visitors

Chinese retailer AliExpress has been found using an audio trick to fingerprint visitors.

This technique analyzes inaudible audio signals processed by web browsers.

Researcher Matthew Callaghan discovered this method after noticing his phone audio stopped playing.

Firefox and Chrome browsers now have protections against this specific audio fingerprinting method.

AliExpress employs multiple other tracking methods alongside this audio technique.