Billions of Bluetooth-connected devices impacted by new BIAS weakness

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A group of academic researchers have discovered a new vulnerability in the Bluetooth wireless protocol that affects almost all Bluetooth enabled devices.

The vulnerability, which they have decided to refer to as Bluetooth Impersonation AttackS (BIAS), impacts the classic version of the Bluetooth protocol that is used by low power devices to transfer data and is commonly referred to as Bluetooth Classic.

The BIAS security flaw leverages the way that devices handle link keys or long-term keys that are generated when two Bluetooth devices pair for the first time. The devices agree on a long-term key that is then used to connect paired devices in the future so that users don't need to go through the pairing process each time they want to use their devices.

In a new paper detailing their discovery, the researchers explain how they found a bug in this post-bonding authentication process. An attacker can exploit the flaw to spoof the identity of a previously paired device and successfully authenticate and connect to another device without first obtaining the long-term pairing key that was previously established between two devices. A successful BIAS attack allows an attacker to access or even take control of another Bluetooth Classic device.

BIAS attacks

The researchers explained that they tested and found that many Bluetooth devices are vulnerable to BIAS attacks in a post, saying:

“The BIAS attack is possible due to flaws in the Bluetooth specification. As such, any standard-compliant Bluetooth device can be expected to be vulnerable. We conducted BIAS attacks on more than 28 unique Bluetooth chips (by attacking 30 different devices). At the time of writing, we were able to test chips from Cypress, Qualcomm, Apple, Intel, Samsung and CSR. All devices that we tested were vulnerable to the BIAS attack.”

After making and disclosing the security flaw in December of last year, some vendors may have implemented workarounds for the vulnerability on their devices. However, if your devices have not been updated since that time, they are likely vulnerable.

Thankfully though, launching a successful attack is not that easy as an attacker's device would need to be within wireless range of a vulnerable Bluetooth device that has previously been paired with a remote device with a Bluetooth address known to the attacker.

TechRadar Pro reached out to the Bluetooth Special Interest Group (SIG) regarding BIAS attacks and a spokesperson for the group explained that it works with developers and the security research community to help protect all Bluetooth devices, saying:

“The Bluetooth Special Interest Group (SIG) prioritizes security and the specifications include a collection of features that provide developers the tools they need to secure communications between Bluetooth devices. The SIG also provides educational resources to the developer community to help them implement the appropriate level of security within their Bluetooth products, as well as a vulnerability response program that works with the security research community to address vulnerabilities identified within Bluetooth specifications in a responsible manner.”

Via ZDNet

Anthony Spadafora

After working with the TechRadar Pro team for the last several years, Anthony is now the security and networking editor at Tom’s Guide where he covers everything from data breaches and ransomware gangs to the best way to cover your whole home or business with Wi-Fi. When not writing, you can find him tinkering with PCs and game consoles, managing cables and upgrading his smart home.