Is it possible to some kind of trojan/virus to undermine Norton Vault security?

A couple of days ago an odd situation occured... No updates or upgrades were done by the way, and I needed to open my password vault just as my every day internet routines, I was very surprised that instead of being prompted to insert my vault password I was asked to fill in my Norton account data and only afterwords was I able to open my vault as usual, I use the cloud vault and this was like I was using it  for the very first time. Is this something normal to happen or could my laptop be infected with some trojan that aims to steal the vault data?

I must add that I did a full scan right after this situation and 3 virus were caught, however I don't know if any were of such a kind.

I'm worried...Should I change all my logins & passwords?