Front wheel hub making zunning sound

This is my first bike, and doing some search I can imagine that has to do with the grease in the hub. We traveled and the bike was stationary for almost 4 weeks, inside our apartment box which is covered from rain, but open, so probably got very humid as it rained a lot.

Is that something I can easily fix at home ? If that is indeed the case, and I could do it, can you recommend some video or article.

Thanks!