If you have no down payment and your credit is bad, you can't buy. At least not a foreclosure. If it were a property owned by an individual, you could try a lease-option. Or a subject-to. But neither will work with a foreclosure.
Basically, the bank wants to sell the property. You're not able to buy it. Look: Talk with all the lenders you want. "I have no money for a down payment and my credit is bad." Sorry, but that won't get you very far. There's no magic solution. You have to save up some money and improve your credit.