SWRA674 May 2020 – MONTH CC1350 , CC1352P , CC1352R , CC2560 , CC2560B , CC2564 , CC2564C , CC2564MODA , CC2564MODN , CC2640R2F , CC2640R2F-Q1 , CC2640R2L , CC2642R , CC2642R-Q1 , CC2650 , CC2652P , CC2652R , CC2652R7 , CC2652RB , CC2652RSIP , WL1831MOD , WL1835MOD , WL1837MOD
Publication date: May 18, 2020
Bluetooth® Special Interest Group (SIG) has issued recommendations based on findings from researchers at the Technical University of Munich (TUM) regarding a potential security vulnerability, enabling an attacking device to successfully intercede as a man-in-the-middle between two pairing devices. To do this, the attacker must negotiate a numeric compare procedure with one device and a passkey pairing procedure with the other, and the user must erroneously enter the numeric compare value as the passkey and accept pairing on the numeric compare device.
Potentially impacted features
An attacking device would need to be within wireless range of two vulnerable Bluetooth devices that were establishing either an LE or a BR/EDR encrypted connection using the passkey entry or numeric comparison for device authentication without existing shared credentials (LTK or link key). At least one device must permit entry of a passkey, and the other must support a display capable of representing six decimal digits.
All devices supporting BluetoothLE Secure Connections Pairing and Secure Simple Pairing are potentially vulnerable to this attack. Bluetooth SIG suggests recommendations that can be implemented at the application layer. Please see the Bluetooth SIG notice regarding the Method Confusion pairing vulnerability for details.