It’s about the easiest thing ever to look up the owner of the property in most counties in the US. Most counties have their deeds and records in a searchable format online and you can generally search by address. In the market where I work, you can look here:
The problem is that knowing the name and address of the bank that owns a foreclosed home won’t do you any good at all if you’re trying to either buy the property or try to get the bank to do anything with/about the property. The foreclosure deed will show the mailing address where the property tax bill is sent, but if you try to reach out to the bank, you’ll hit a stone wall. The asset manager who is responsible for the bank is a nameless, faceless cog in a huge machine and they have no interest in hearing from your or helping you.
Your best bet, if you’re trying to buy a house that’s been foreclosed, is to buy it from the owner before the foreclosure, buy it at the foreclosure sale, or buy the redemption rights from the previous owner and redeem the property. After the bank has foreclosed and the property has reverted to the lender because nobody bid at the foreclosure auction, you really do have to wait until it’s listed on one of the auction websites or with a local realtor.