https://www.bleepingcomputer.com/news/security/tens-of-thousands-of-android-devices-are-exposing-their-debug-port/

The security community raised the alarm regarding a serious issue last week —that of Android devices shipping with their debug port open to remote connections.

The issue is not new, being first spotted by the team at Qihoo 360 Netlab in February, this year, when they detected an Android worm that was spreading from Android device to Android device, infecting them with a cryptocurrency miner named ADB.Miner.