How to remove adware from system folders

[AC Question]

I recently purchased an Asus Zenfone 2 (ZE551ML) from Android Enjoyed. It came from overseas, so I don't know what's gone on behind the scenes. I have been getting pop up ads (e.g. congratulations zenfone user, you have won an iphone 6). I ran a kapersky full system scan and it has picked up 2 threats. One is in /system/priv-app/PreInstall.Preinstall.apk and is called "not-a-virus:HEUR:AdWare.Android.OS.Sprovider.o (can't read the rest). The other is in /system/app/QuickSearch/QuickSearch.apk and has the same name. I took my phone to an IT guy who said it is easy to remove, just hook it up to your computer, explore to the file and delete. So I did that, found the folder (but couldn't see the apk file), and deleted. Ran the scan again, found the threats again, and the files magically appeared back in those folders. Incidentally, the folders with the suspicious files in them are the only ones I can see when I hook my phone up to my computer.

Would appreciate any help. Kapersky won't delete the files because they are in my system folder. Kapersky has been the only program that will detect these threats too.

Thanks to anyone who can help.

 

[reactorh]

I recently purchased an Asus Zenfone 2 (ZE551ML) from Android Enjoyed. It came from overseas, so I don't know what's gone on behind the scenes. I have been getting pop up ads (e.g. congratulations zenfone user, you have won an iphone 6). I ran a kapersky full system scan and it has picked up 2 threats. One is in /system/priv-app/PreInstall.Preinstall.apk and is called "not-a-virus:HEUR:AdWare.Android.OS.Sprovider.o (can't read the rest). The other is in /system/app/QuickSearch/QuickSearch.apk and has the same name. I took my phone to an IT guy who said it is easy to remove, just hook it up to your computer, explore to the file and delete. So I did that, found the folder (but couldn't see the apk file), and deleted. Ran the scan again, found the threats again, and the files magically appeared back in those folders. Incidentally, the folders with the suspicious files in them are the only ones I can see when I hook my phone up to my computer.

Would appreciate any help. Kapersky won't delete the files because they are in my system folder. Kapersky has been the only program that will detect these threats too.

Thanks to anyone who can help.

You need an anti Spyware running on your device

 

[Asus_user]

Thanks - I ran Incognito Free Spyware and Malware Remover and it did not detect anything. Update - I have now done a factory reset on my phone and it's still there.