Ads page opening on browser startup I'm getting incredible bored of this situation.

2 different friends phone got infected with some kind of ads-malware that open internet page at random while navigating with news, shopping and google fake searchbar.

I've joked they for weeks for let getting this 'malware' (nb: undetected by all antimalware apps that I know) installed on their phone (nb: different models, different carrier, no root, never connected to the same wifi. Basically never encounted). They simply download app from playstore, do web browsing and using whatsapp and telegram... They use in a 'casual' way their phone and they seriusly don't know what they are done wrong...

Today I've got a similar problem and I seriously don't know what I've done, cause I didn't have installed any app since several months, didn't used anything aside chat app and gone through the same 3-4 website I check usually.

What's the problem?: every time I open a browser (whatever it is, chrome or firefox) it try to open a page full of spam and sh1t. If I press HOME button and reopen again the browser I got another tab with the same page... And so on: if I tap 10 times on chrome or firefox app icon it will open 10 tabs that redirect on that crap site.

The deal is that I usually use firefox with adblock and ghostery and it's strange that I got infected with something.

I've not installed nothing strange, and nothing at all since 2 months ago. I didn't done any app update since...ever. I'm using 5.1. I think maybe I got something surfing the web, but I can't discover what or HOW I got screwed.

Also I can't get rid of this, tried everything I know: cleared ads ID, cleared cache and checked dns and....nothing.

How can Android be such insecure? How can I understand what's causing it? Any ideas?
It may be an app installed on your phone that is displaying ads while also running in the background. Uninstall any apps you feel display an excessive amount of ads if you don't need them. Also, depending on the phone OS you can go to the recent apps and see a "screenshot" of what process you are doing on the app. if it shows an ad on that screenshot, then that is the app which is doing it.

If your problem is the web browser then uninstall and reinstall those apps again. Do not add any extensions and see how the apps work.

If you are receiving any type of virus or malware then I would recommend using Avast Antivirus or some other virus remover app that checks the contents of your phone and wipes away the virus.

If you've been through these 2 steps, and the problem still persists, you may have to go through and flash your phone with the stock image again. This will remove all your data, but at least you'll know you don't have a virus on your phone anymore.