Privacy

There's also Bluetooth radios all over, and those tire pressure monitoring systems, which I understand are legally-mandated on new cars, broadcast a unique identifier.

https://askmyauto.com/are-tire-pressure-sensors-required-by-law/

Are Tire Pressure Sensors Required by Law? A Comprehensive Guide

October 15, 2024

Yes, tire pressure sensors (TPMS) are required by law in several countries. In the United States, TPMS has been mandatory for all new passenger vehicles since 2007 under the TREAD Act. Similarly, the European Union mandates TPMS in new cars sold after 2014.

https://medium.com/@doctoreww/day-2-your-car-is-trackable-by-law-1d5f74388850

To prevent TPMS systems from mixing up which tire goes to which vehicle, each TPMS sensor has a unique ID. The transceiver module in the car is told which sensor ID’s go to which tire and displays tire pressure accordingly. TPMS sensors can be forced to immediately send the tire pressure (and thus their ID) when the receive a particular signal. This signal is used in products like this to send pair the TPMS to the car.

Problem

Although a unique ID can be used to avoid other TPMS sensor’s messages on the road, this unique ID can also be used by an attacker to track a vehicle’s movements. This ID is broadcasted unencrypted and, therefore can be used to track when a particular vehicle has passed nearby.