Devices supporting the Bluetooth Core and Mesh Specifications are vulnerable to impersonation attacks and AuthValue disclosure that could allow an attacker to impersonate a legitimate device during pairing.
The Bluetooth Core Specification and Mesh Profile Specification are two specifications used to define the technical and policy requirements for devices that want to operate over Bluetooth connections. Researchers at the Agence nationale de la sécurité des systèmes d’information (ANSSI) have identified a number of vulnerabilities in each specification that allow impersonation attacks and AuthValue disclosures.
Devices supporting the Bluetooth Core Specification are affected by the following vulnerabilities:
Impersonation in the Passkey Entry Protocol
The Passkey Entry protocol used in Secure Simple Pairing (SSP), Secure Connections (SC), and LE Secure Connections (LESC) of the Bluetooth Core Specification is vulnerable to an impersonation attack that enables an active attacker to impersonate the initiating device without any previous knowledge (CVE-2020-26558). An attacker acting as a man-in-the-middle (MITM) in the Passkey authentication procedure could use a crafted series of responses to determine each bit of the randomly generated Passkey selected by the pairing initiator in each round of the pairing procedure, and once identified, the attacker can use these Passkey bits during the same pairing session to successfully complete the authenticated pairing procedure with the responder. Devices supporting BR/EDR Secure Simple Pairing in Bluetooth Core Specifications 2.1 through 5.2, BR/EDR Secure Connections Pairing in Bluetooth Core Specifications 4.1 through 5.2 and LE Secure Connections Pairing in Bluetooth Core Specifications 4.2 through 5.2 are affected by this vulnerability.