[Q] Phone seems to be infected by a Trojan
A few days ago my phone arrived from Ebay. I set it up and all was OK until I put it on the wireless charger. Then I noted that someone started to remotely operate the phone - to switch applications and so on.
During the set-up I upgraded to 4.3 and installed stuff from big and known companies (Facebook, Microsoft, etc.), all from Google Play. I haven't installed anything else. Usually I am very careful with what I install on my devices because I've been developing software for long time and have some experience with security (although this is my first Android phone).
After I noted the issue I restored the phone to its factory settings, installed even less apps, however I experienced the same. The hacker even wrote something playful.
Could you pls tell me how to find out what is going on? Like how was it possible to put a Trojan that would survive an Android update and a factory restore? How to find the Trojan and so on. I later installed some antivirus/antimalware that reported that the phone is clean.