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.

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

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.