What does my Android with the Internet secretly?

[AC Question]

What does my android with the Internet secretly?

A few weeks ago, my Samsung Galaxy A3 SM-A300M with Android 4.4.4 KitKat, use all the bandwidth of my Internet connection when I connect to WiFi.
At the begin it happens just when the phone is getting charged and was connected by wifi, but now getting to home i connect it to wifi and after a few minutes of use, it begin to climb the use of the network to literally remove the speed of other devices connected to the same wireless network. It's like my phone is uploading something to internet but i didnt configured any back up or cloud services. Maybe my phone have a infection, virus, i dont know.
At my pc try to surfer the webs, but the internet get so slowly, when i try to do a speedtest it gave me a 1000ms of ping and poor download/upload speed. Yesterday a root my phone and after the root all works very fine and when i connect it to wifi nothing of this problem happens, so i dont know whats is really happen. It is very annoying, also try to scan the network usage using this app "Network Connections" with this app but just the android services uses my network when the phone is blocked, also i dont install apps outside of the google play store.
Please help me understand what is happening.

 

[Rukbat]

Rooting just adds a file and an app to the phone, it has nothing to do with data usage. It could be an app going crazy or a virus. Run a virus scan, run Malwarebytes Anti-Malware and restart in safe mode to see if it's a bad app.

 

[xandros9]

Any chance it could be some kind of backup?

 

[Javier P]

Re: What does my android with the Internet secretly?

You could check which apps used most of that data in settings - data usage - WiFi tab. I think this was already possible on kitkat and you can even change the dates to have a better idea of what was going on in the past.