My android phone is often getting affected with virus My problem :

Hello friends. I use Asus zenfone go T500 android phone. My problem is, my phone often gets affected by some kind of virus which sometimes installs some chinese apps without my knowledge and sometimes it causes troubles to other system apps and because of this i fequently get a message displaying unfortunately stopped working.

What I have done:


I tried resetting my phone(factory reset).
But even after resetting after a few days the same problem occurs again. So i thought of reinstalling my stock rom and hence i downloaded the stock rom from the official asus site and reinstalled it. Everything was fine. But again after some days the same problem. What i mean here is no matter any time i scan my phone with some antivirus or factory reset or reinstall ROM the behavour still exists.
I tried updating all my system and installed apps but no use.


My predictions:

What i predicted as a problem was this that my phones private ip address must have been stolen somehow and some idiot from some country is DOS attacking my phone.

Other info


  NOTE: I once rooted my phone and then later i reinstalled the stock
  ROM to get rid of it


My phone: ASUS Zenfone GO LTE

Model: ASUS_X003 (T500)

OS: KitKat - 4.4.4

ROM: WW-SKU
Lots of malware writers make malwares to make money, so developing a virus would do no good to them. Better ways of making money is to force installation of some apps which loads ads for you, or collects your personal data and sells it to third-parties, or just plainly demand ransom for your personal data. Check out this list to know the categories of Android malwares.

Whenever you get into a problem repeatedly you should wonder why so? In this case the biggest problem is you (the user) using an archaic version of Android that was launched in 2013 (6 years ago!). Neither Google, nor your OEM would support the device for that long. Meanwhile, since OS is actually a software built using codes,and because codes can be buggy the bugs get exploited by some malwares writers and the result is what you are experiencing with your device. 

The only solution as I see is to keep reviewing the code for vulnerabilities and fixing them. This is near impossible for users so we expect OS developers or OEMs to do this for us. Some OEMs support the device for some period, others don't. In that case, the user can turn elsewhere and see if some third-party is doing this job (custom ROM developers). If even that doesn't work, one should either stop using the device with any new app or updates or with internet connectivity, or to personally port a custom ROM built using secure and new OS code, or simply switch to a device which uses the latest Android version and would be supported for a while. 

To summarize, there is no point in fixing this problem technically because your device is asking itself to get compromised again, sooner or later. Switch to a newer Android version.

Note: it may be possible to prevent exploitation of some vulnerabilities in an older Android version using SELinux or some other security framework, but I am not aware of any attempt in this direction.