Bluetooth is a short-range wireless standard in the 2.4 GHz band that connects headphones, keyboards, wearables, cars and IoT devices to phones and computers.
How Bluetooth works
Bluetooth is developed by the Bluetooth Special Interest Group (SIG). It uses frequency hopping in the 2.4 GHz ISM band, usually over distances of up to about 10 metres, although newer devices can reach much further. There are two main flavours:
- Bluetooth Classic (BR/EDR) – continuous connections, for example for audio;
- Bluetooth Low Energy (BLE, since version 4.0) – very low power for fitness trackers, smart locks, beacons and medical devices.
Devices are first paired: they exchange keys and then encrypt the connection. In current terminology one device acts as the central and others as peripherals.
Why Bluetooth matters for security
Bluetooth stacks are complex and run with high privileges, so bugs can be serious. Well-known examples are BlueBorne (2017), which allowed remote code execution without pairing, KNOB (2019), which forced very short encryption keys, BIAS (2020), which let an attacker impersonate a paired device, and BLUFFS (2023), which broke the secrecy of sessions. Other risks include tracking via BLE advertisements, weak pairing in cheap IoT devices and data theft through insecure smart locks.
How to protect yourself
- Install firmware and OS updates for phones, laptops, cars and headsets.
- Turn Bluetooth off or make devices non-discoverable when not needed, especially in public places.
- Pair new devices in private places and reject unexpected pairing requests.
- Choose IoT devices from vendors that publish security updates.
