You got a great answer from Charles. I just wanted to add that even with a Regular Sale through MLS, VA loan would require to fix the house to a standard and/or livable conditions before they fund the loan.
I think it's very high risk unless you know the house in very good conditions.
There is no financing at all for the typical trustee's Auction that takes place on the courthouse steps.
However for many of the other Real Estate Auctions, arrangements are made for financing the transaction the same as if it were a regular sale through the Multiple Listing Service.