Bluetooth SIG—an organization that oversees the development of Bluetooth standards—today issued a statement informing users and vendors of a newly reported unpatched vulnerability that potentially affects hundreds of millions of devices worldwide.
Discovered independently by two separate teams of academic researchers, the flaw resides in the Cross-Transport Key Derivation (CTKD) of devices supporting both — Basic Rate/Enhanced Data Rate (BR/EDR) and Bluetooth Low Energy (BLE) standard.
Cross-Transport Key Derivation (CTKD) is a Bluetooth component responsible for negotiating the authenticate keys when pairing two Bluetooth devices together, also known as “dual-mode” devices.
Dubbed ‘BLURtooth’ and tracked as CVE-2020-15802, the flaw exposes devices powered with Bluetooth 4.0 or 5.0 technology, allowing attackers to unauthorizedly connect to a targeted nearby device by overwriting the authenticated key or reducing the encryption key strength.
“Dual-mode devices using CTKD to generate a Long Term Keys (LTK)or Link Key (LK) are able to overwrite the original LTK or LK in cases where that transport was enforcing a higher level of security,” the researchers explain.