https://www.wired.com/story/146-bugs-preinstalled-android-phones/
When you buy an Android smartphone, it’s rarely pure Android. Manufacturers squeeze in their own apps or give it a fresh coat of interface. Carriers do it too. The resulting stew of preinstalled software and vanilla Android sometimes turns out to be rancid, putting flaws and vulnerabilities on the phone before you even take it out of the box. For proof of how bad it is, look no further than the 146 vulnerabilities—across 29 Android smartphone makers—that have just been simultaneously revealed.