Security experts have spotted a version of the Linux Kernel (Linux 3.4-sunxi kernel) shipped by the Allwinner affected by a built-in backdoor that is easy to exploit. In order to gain root access of an affected Android device, the attacker needs to send the text rootmydevice to any undocumented debugging process. The code related to the kernel backdoor was published on PasteBin it is available, once it. triggers a local privileges escalation for. debugging ARM-powered devices.”]
Source: https://securityaffairs.co/wordpress/47272/hacking/kernel-backdoor-allwinner.html