BD_ADDR (Bluetooth Device Address)
Definition
The 48-bit hardware address assigned to each classic Bluetooth device by its manufacturer. Analogous to a MAC address on Ethernet. Unlike BLE random addresses, a classic BD_ADDR is fixed and persistent, making it a reliable identifier across pairing records, logs, and packet captures.
- Length
- 48 bits (6 bytes)
- Format
- Written as six colon-separated hex octets
- Analogue
- Ethernet MAC address
- Persistence
- Fixed, unlike BLE random resolvable addresses
- OUI segment
- Upper 24 bits identify the chipset manufacturer
Common questions
Why does BD_ADDR matter more than a BLE address in an investigation?+
Classic BD_ADDR does not rotate, so it can be correlated across an evidence timeline: pairing logs on a phone, packet captures from a sniffer, and access-point association records can all be tied to the same physical device with confidence.
Can a BD_ADDR be spoofed?+
Yes. Many Bluetooth chipsets let firmware or software set the address field, so a captured BD_ADDR should be corroborated with other identifiers, such as the device name, service UUIDs, or link key, rather than treated as unforgeable on its own.
Related terms
- GATT (Generic Attribute Profile)
- The protocol framework used by BLE for data exchange. A GATT server exposes data as Services and Characteristics; a GATT client reads...
- Link Key / Long-Term Key (LTK)
- The cryptographic secret negotiated during Bluetooth pairing that is stored on both devices and used to authenticate and encrypt subsequent connections. In...
- Resolvable Private Address (RPA)
- A BLE address type that rotates on a timer (typically every 15 minutes) but can be resolved back to the device's true...
- RFCOMM
- Radio Frequency Communication, the Bluetooth protocol that emulates a serial RS-232 connection over an L2CAP channel. Used by profiles including Serial Port...
- Ubertooth One
- An open-source USB Bluetooth sniffing platform developed by Michael Ossmann that can capture raw Bluetooth BR/EDR and BLE frames from the air....