How to get rid of the "My apps" malware

[LuiTheKang]

Hello all, I hope you can help me to deal with my android malware - I've searched many forums and I haven't seen anywhere mentioned this problem.

I have bought a phone - UMI Diamond, Android 6.0 - from EU store.
Its fast, its good, it works well.

But time to time the following things happen:
- in Security settings the installation from "Unknown sources" switch is turning on automatically (Avast perceives it and suggests to turn it off immediately, but doesn't blocks it...);
- appears (automatically installs) an application named "My apps", which has access permissions to everything, has some internet usage and like 10MB data storage use;
- after unlocking the phone a whole page covered ad appears to install some different applications;
- clicking somewhere even in a trusted application opens Chrome with a new page, redirects to a page very similar to the Google Play to install an application (always an other).

I reviewed my phone with different anti malware and virus applications - none find anything.

Can you please suggest me something to get rid of it?

Many thanks in advance,
Lajos


--- EDIT:

I have finally found users with similar problem with UMI Diamond phone on UMI Community Forum
and there I have found the solution:
UMI COMMUNITY-UMi Diamond-Release : Umi Diamond Custom Rom Kleenex Edition - Powered by Discuz!

 

[Hikari Kobushi]

I have had the same issue with my previous Blackview phone. Thing I did is I installed different firmware on it and since then all suspicious malware apps were gone. I have done quick Google search about your phone and I did not find any ROM but official one. In that case you could try reinstalling it. You can find ROM and custom recovery on needrom.com