Virus or not virus?

Question

Computer networks

Hello. I hope you can help me clarify the situation, although this happened six months ago, it still haunts ...
I will say right away that I am paranoid in terms of visiting suspicious sites, downloading files, and so on. Only torrents or files checked by virustotal.
It all started with the fact that an invisible "film" appeared in the browser on the entire page, thanks to which, wherever you clicked on the page, there was a redirect to suspicious sites. At first, I didn’t really notice this, because the caring Fire Fox immediately closed the pop-up new windows, and so quickly that I couldn’t notice it at all. But once I clicked on a few tabs with the wheel, I was horrified to find that these were not posts that interested me at all, but some unknown crap, I closed everything in horror. I looked in the magazine, so to speak, from a safe distance at all these links - well, for sure, any website brood.
For a long time I thought about how to get rid of this crap. I ran it with various programs, CureIt !, Kasperych, AVG, AVZ, there are some more, in short, all that I found by googling this topic. There was nothing. I wrote to all the enikey people I knew - no one could help. The infection was on all browsers, even unpopular ones. You probably already guessed what it was. How happy I was to guess that the problem comes from the router settings :) I went there and saw an oil painting: left DNS. Several times I changed them to Google ones as an experiment - the problem disappeared for a day, then all over again. Pass / login to the router interface, of course, were default (admin / admin). I changed the password to complex and it all stopped. However, this still torments me: how did DNS change? Who or what did it? I still run the computer, just in case.

Answer 1

You do not need to drive away the computer, but your router.
When buying / setting up a new router, the first thing you need to do is go to its settings and change the admin password. Then you can look at the manufacturer's website for the latest firmware.
Ideally, even before buying a router, look for reviews about it on independent sites, and at least the same toaster and stackoverflow about articles with engineering passwords.