Google confirms that advanced backdoor came preinstalled on Android devices - Ars Technica

https://arstechnica.com/information-technology/2019/06/google-confirms-2017-supply-chain-attack-that-sneaked-backdoor-on-android-devices/

Criminals in 2017 managed to get an advanced backdoor preinstalled on Android devices before they left the factories of manufacturers, Google researchers confirmed on Thursday.