A recently discovered vulnerability in Bluetooth technology, designated as CVE-2020-26558, presents a serious security threat to devices adhering to various Bluetooth Core Specifications. Known as “Impersonation in the Passkey Entry Protocol,” this flaw affects devices using the Passkey Entry association model in several pairing methods, including BR/EDR Secure Simple Pairing, Secure Connections Pairing, and LE Secure Connections Pairing.
The vulnerability spans Bluetooth Core Specifications from version 2.1 through 5.4 for BR/EDR and from version 4.2 through 5.4 for LE Secure Connections, making a wide array of devices susceptible to potential exploitation. The vulnerability allows a man-in-the-middle (MITM) attacker to take advantage of the pairing process by responding to an initiating device with a public key that matches the peer device’s X coordinate.
Through crafted responses, the attacker can glean the passkey utilized during the pairing session, facilitating an authenticated pairing procedure with both the initiating and responding devices. This attack can be executed if the attacker is within wireless range of two vulnerable Bluetooth devices that are initiating pairing or bonding, highlighting the importance of addressing the flaw in environments where Bluetooth devices frequently connect. To mitigate the risks associated with CVE-2020-26558, Bluetooth Core Specification 5.4 recommends that devices abort a pairing procedure if a peer’s public key X coordinate aligns with that of the local device, except in cases involving a debug key.
This measure will become mandatory in the upcoming Bluetooth Core Specification 6.0. Manufacturers and developers are urged to follow these guidelines and update their implementations accordingly, as rejecting public keys with matching X coordinates is essential for preventing potential MITM attacks and bolstering overall security. The Bluetooth Special Interest Group (SIG) emphasizes the need for adherence to updated security protocols to guard against vulnerabilities like CVE-2020-26558.
Users are encouraged to regularly update their devices and remain informed about security patches released by manufacturers. As Bluetooth technology evolves, maintaining strong security measures is vital for protecting personal data and ensuring secure wireless communications across various devices.
Reference:
- https://www.bluetooth.com/learn-about-bluetooth/key-attributes/bluetooth-security/passkey-impersonation/
