I recently installed Trend Micro Mobile Security in order to to check my apps if all are safe and secure since I have a rooted Xperia Phone which may be more prone to attacks.
I had clean results then I've got it uninstalled. The problem starts when I installed an App called "WiFi FTP (WiFi File Transfer)" from 1 Mobile Market which I found out isn't a genuine Google Play app and has a suspicious 1MB file size. As a rooted user I've got a popular app called Xprivacy which warns me when any app is seeking permissions and gives me the choice to allow it or not.
When I opened WiFi FTP and gave it full permissions it needed I had a surprising Xprivacy popup for another app called "Security Certificate" asking for permissions to use (among others) the Internet. I've blocked all of them. After removing WiFi FTP I had another popup for a suspicious app with the name "Settings Helper" asking for the same permissions as its predecessor. I blocked all permissions it was asking for, and opened Settings > Apps to check what they are. I found both of them having an identical weird android logo and when I got into the app info it had a "Disable" option not an "Uninstall" one. Which means that it is installed as a system app. Though I disabled both of them, and when I was outdoors I turned on Mobile Network for internet access just for 5 seconds and found a surprising big charge,and after checking traffic data usage I found an app (or better call them a system service for the three of them) with the same weird logo called "ceryos" that was the reason for that unusual charge and the previous two apps with some minimal net usage too!
I disabled the three apps but after some hours I checked them back and found them enabled Again except for "ceryos" (luckily)! And resetting the permissions limits I set them to from xprivacy. Though after doing more checks I found another one called "Live Wallpaper" with the same icon and disabled it.
What is the safest way to disable or remove these malicious applications?