Android 5.0 suspicious ads and methods of struggle?

Question

Android

there is a tablet on 5.0 androyd and a problem: advertising appears on the whole screen exactly at the time at which the standard alarm clock is set.
1) I thought it was a virus - I ran it with Kaspersky and dr web - there are no viruses
2) I thought it shows the application - I deleted all applications except Google, Word and Microsot rdp client. Did not help.
What kind of nonsense and how to find the application where this ad comes from?
PS Put a firewall to catch the bastard. The glmedia app is showing ads. Question - What to do with it and how to clean it? There is no application in the list, it seems like a system one.

Answer 1

If there is no root: Uninstall updates for all non-removable applications, look at the behavior. If the ads have disappeared, then it means that some Chinese application started acting up after the update, update one thing and watch, so by updating one by one you will find the advertiser.

Answer 2

This often happens on Chinese phones sewn into the system. Can't be removed without root. Climb on w3bsit3-dns.com, look for instructions on rooting, and maybe even find instructions on disabling ads.

Answer 3

Also send it for verification from the "selective check" of Doctor Web, it will be checked and added to the database if it is really advertising, which will make life easier for other users)