Devices can be tracked even when offline and invade your privacy
You have seen this in action/spy/Sci-Fi movies and shows, the protagonists always remove the battery of their phones to make sure it cannot be used. Most people would think that’s overkill. Well, unfortunately, no, this is now becoming true at least for some devices:
- iPhones and iPads (IOS 13 and above)
- Samsung Phones (Android 10 and above)
- MacBooks (macOS 10.15 and above)
Such devices will continue to broadcast identity information to nearby devices even when offline using Bluetooth Low-Energy. They do not have access to the devices directly (which are not connected to the internet) but instead use BLE to find them through other nearby devices. They are using peer-to-peer short-range Bluetooth communication to broadcast their status through nearby online devices.
They could now find such devices and keep the location in some database that could then be used by third parties or themselves for various purposes (including analytics, advertising, or evidence/intelligence gathering).
TLDR: Do not take such devices with you when conducting sensitive activities.
Source: The Hitchhiker’s Guide to Online Anonymity, written by AnonyPla © CC BY-NC 4.0