Squealing brakes on Fabia 2001

Hello everybody.

I digged through some old posts, but couldn't find any directly related to this thing. (Maybe it's because I am still very car illiterate, who knows ) I just bought a 2001 Fabia 1,4 MPI from a dealership.

The brakes, most likely the front ones are shrieking when I am braking - much less in rainy weather than in dry weather. I therefore suspected rust and did some emergency brakings and also drove a short distance with the handbrake applied that much, that I could feel it was slowing down the car. The squealing however continues.

Is this just a case of brake dust/brakes needing lubrication (prolly not the correct word ) or could this be a sign of brake discs needing changing? It was raining when I tried the car at the dealership and hence I didn't notice. If this is a serious issue, I should go back and complain to the dealership.