Google has issued a critical security update for Android that affects the Bluetooth functionality on about two-thirds of all Android devices now in use.
The vulnerability, CVE-2020-0022, affects devices running Android Oreo (8.0 and 8.1) and Pie (9.0) and can allow remote code execution without any user interaction. The flaw was found and reported to Google three months ago by the German security firm ERNW with a patch being issued last week. However, any devices not updated remain vulnerable through their Bluetooth connectivity.
ERNW found that devices running Android 8.0 through 9.0 can be accessed by a nearby malicious actor who can exploit the flaw to run code or remove data without the device owner having to take any action to help the attack. The attacker does need to know the Bluetooth MAC address of the device being assaulted, but this can often be deduced from the local WiFi Mac address.
The threat actor does need to use a specially crafted Bluetooth transmission that contains more data than expected leading to memory corruption, Google reported.
Products running Android 10 are somewhat less vulnerable as the bug, if exploited, will only crash the device and not give access to the attacker.
ERNW did not check if earlier Android versions are susceptible.
For those for whom a patch is not available the company recommends turning off Bluetooth when its not needed and to make sure the device is in undiscoverable mode.