Why Bluetooth Devices No Longer Work After Installing June 2019 Windows Updates

Select Bluetooth devices are no longer allowed to pair with Windows computers after installing the June 2019 security updates.

Microsoft revealed in an advisory that it decided to block the pairing of devices using Bluetooth Low Energy (BLE) keys because of a security flaw that could allow an attacker to intercept pairing keys.

“Microsoft is aware of an issue that affects the Bluetooth Low Energy (BLE) version of FIDO Security Keys. Due to a misconfiguration in the Bluetooth pairing protocols, it is possible for an attacker who is physically close to a user at the moment he/she uses the security key to communicate with the security key, or communicate with the device to which the key is paired,” it says.

In other words, because of a bug in the Bluetooth pairing protocols, an attacker can intercept the pairing codes and then be able to connect to the target device without authorization. From this point on, it’s all up to the attacker to decide how much damage they want to do on the compromised system.

Microsoft notes that any device that use well-known keys to encrypt connections might be disabled, and the company provides some resources for users whose devices might be impacted.

First and foremost, the following updates are said to be blocking the pairing of insecure devices:  

First of all, you should try to determine if your device is affected or not. To do this, you need to use the Event Log by launching the Event Viewer:

At this point, it’s not known how many Bluetooth devices are impacted, but given the bug targets all latest versions of Windows, including all Windows 10 releases so far (May 2019 Update is also on the list), blocking the pairing could help protect a significant number of users.