Ultrasonic Cross-Device Tracking

Forget about the “old days” when Cookies were used by advertisers to identify our interests across the web. Cookies were also used by companies to improve the user experience, enabling users to pick up where they left off on websites. However, as users began using multiple devices, advertisers became confused as to how to track, manage, and consolidate this data across multiple devices as the cookie-based model suggested that each device––whether a phone, computer, or tablet––was a different person.

Then came other technologies such as supercookies, which stay on computers long after the user deletes his or her cookies, and web beacons, which are unique images from a website URL, are also used by trackers and advertisers to gain increased insight into a users’ behavior. However, advertisers were still limited in that only one device was able to be tracked and associated with a user.

Ultrasonic cross-device tracking refers to a method of tracking users across multiple devices by leveraging ultrasonic signals, typically transmitted through the air. This technology can be used to link a user’s activity on one device, like a mobile phone, with their activities on another device, like a smart TV, based on proximity.

Here’s a more detailed explanation:

How it works:
Ultrasonic tones (usually between 18–22 kHz) are sound waves above the human hearing range that can be transmitted from one device to another. These signals can be used to identify a user’s presence and link them to other devices that are also using ultrasonic tracking.

Purpose:
The primary goal of cross-device tracking is to gather a comprehensive view of a user’s online activity across different devices. This allows for more targeted advertising, personalized content, and other services. Marketers LOVE this technology because it’s invisible and almost no one’s blocking it yet.

Privacy concerns:
Cross-device tracking raises privacy concerns, as it allows for the collection and analysis of user behavior data across multiple devices. This can lead to the creation of detailed user profiles that may be used for targeted advertising or other purposes.

Example:
Imagine a user watching a movie on their smart TV, and their mobile phone is also using ultrasonic tracking. The ultrasonic signals from the phone can be detected by the TV, linking the user’s activity on the phone to their activity on the TV. This allows advertisers to tailor their ads based on the content the user is watching on the TV and potentially on their phone as well.

Location Tracking:
Ultrasonic signals can also convey location information via location identifiers, often placed in stores or businesses, raising further privacy concerns.

Pretty scary!!!…… Here’s how to protect yourself
Follow the basic steps below. The steps vary by device, so if it’s not exactly as listed, just poke around a little. You’ll find it.

Limit mic access on your devices
iPhone: Go to Settings > Privacy & Security > Microphone. Turn off access for apps that don’t need it.

Android: Settings > Privacy > Permission Manager > Microphone, then deny access for anything that doesn’t absolutely need it.

Turn off tracking on your smart TV
Samsung TVs: Settings > Support > Terms & Privacy > Viewing Information Services, and toggle it off.

LG TVs: Settings > All Settings > General > User Agreements and uncheck Personalized Advertising.

Roku TVs: Settings > Privacy > Advertising, and limit ad tracking.

Stop your smart speaker from storing recordings
Amazon Alexa: Settings > Alexa Privacy > Manage Your Alexa Data > Choose Don’t Save Recordings.

Google Nest/Home: Google Home app > Settings > Privacy > Turn off audio recording

Thanks to WIRED security
https://www.wired.com/2016/11/block-ultrasonic-signals-didnt-know-tracking/