Rooting devices breaks the principle of sandboxing: one app shouldn’t be able to access or modify another app or its data, or system files. If you give an app root, it can do whatever it wants to the system. It could install a keylogger to steal credentials, extract login tokens from another app’s storage or just nuke system files to make your device unbootable.
Let’s say you don’t give any apps root. Even having a rooting platform on the phone (e.g. Magisk) is still a vulnerability. Most rooting platforms will ask the user whether an app should get root when the app requests it. But there could be code execution vulnerabilities (e.g. buffer overflows) in the rooting platform that let you add an app to the list of apps allowed to use root without user confirmation.
TLDR: Root gives an app full access to the device, it could do anything with that. Even if you’re careful with what you give root to, it still adds a lot of attack surface that could be exploited.
Great!
I’m sick of this. We have to defeat it every time it comes up, and there is no doubt it’ll come up again in 2-3 months. They only have to win once and when they do it’ll be in our lives forever.