ALIEXPRESS CAUGHT USING INAUDIBLE SOUNDS TO TRACK USERS

The technique works by emitting frequencies above the human hearing range—typically 18-20 kHz—that are detected by microphones in users' devices. Each browser responds differently to these signals, creating a fingerprint that persists across browsing sessions. While browser fingerprinting itself is common practice for fraud detection and analytics, the ultrasonic approach raises privacy concerns. Users cannot detect or consent to the audio transmission, and the method bypasses standard privacy controls. Security researchers noted the technique is outdated and less reliable than modern alternatives. Nonetheless, its use underscores how companies continue deploying invasive tracking methods. AliExpress joins a history of websites caught using similar ultrasonic fingerprinting tactics to monitor users without explicit permission. The discovery highlights ongoing tension between platform security needs and user privacy expectations in e-commerce.