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Bluetooth BR/EDR Security Vulnerability
Researchers have identified a security vulnerability, known as Key Negotiation of Bluetooth (KNOB), that affects Bluetooth Classic devices (devices using BR/EDR connections). Devices that are Bluetooth Low Energy (BLE) only are not affected by this vulnerability.
Exploiting this vulnerability, an attacker can reduce the negotiated encryption key length to a single octet, allowing a brute force attack to decrypt the data and inject data into a Bluetooth connection. To leverage this vulnerability, the attacker must be within RF range of both devices, have RF capabilities to block and manipulate Bluetooth frames and then run the attack.
- Key Negotiation of Bluetooth or “KNOB" only applies to Bluetooth Classic and Dual mode devices (BLE-only chipsets and modules are not affected)
- KNOB relates to the lack of a minimum encryption key requirement in the Bluetooth SIG specification
- The Bluetooth SIG changed this requirement to a minimum value of seven octets
- If one device is updated to enforce the seven-octet minimum key length, the connection is protected as the key is too long for a brute force attack
- The challenge to the embedded industry is that many end products, including those developed by our clients, do not have the capability to perform a firmware update
- Since most connections involve a phone, tablet, or a PC, patches are already available from Microsoft®, Apple®, Android™, Cisco® and Blackberry® and will be available from other PC or phone vendors soon
- We are currently investigating the impact to existing products as well as possible software fixes for our products