A researcher identified that AliExpress employs an audio-based browser fingerprinting technique after noticing it interfered with his Bluetooth headphone connections. Matthew Callaghan discovered that when loading the AliExpress homepage, audio from his phone would cease playing through multipoint headphones that accept connections from multiple devices simultaneously. He traced the issue to two heavily obfuscated scripts running on the site that generated audio graphs to analyze WebAudio readings from visiting browsers.
The fingerprinting method operates by creating an oscillator that measures Sawtooth waves, which are standard outputs from digital audio systems. The scripts set the audio gain to zero to keep the sounds inaudible to users, yet the browser continues processing the audio signal as it passes through the system’s audio implementation, ultimately transmitting data back to AliExpress. This technique historically exploited variations in mathematical libraries used across different operating systems and CPUs to create unique browser signatures.
However, browser manufacturers have implemented protections against this tracking method. Firefox addressed the vulnerability beginning with version 118 released in 2023 by implementing its own standardized mathematical libraries rather than relying on those provided by the underlying operating system. Chrome similarly ships with proprietary libraries that prevent the technique from functioning effectively, and Safari likely benefits from comparable protections, according to available information.
The discovery raises questions about why AliExpress continues employing an obsolete tracking method when it reportedly uses more than a dozen other fingerprinting techniques. Researchers suggest the audio-based approach may represent legacy code that remained unnoticed rather than a current priority. Security experts note that while browser developers have introduced safeguards, numerous websites likely employ similar tracking tactics, creating an ongoing competitive dynamic as site operators continually develop new methods to circumvent browser protections.
Article Attribution | Read More at Article Source
Article summary produced by Claude AI