Can a bank demand a contractor's social security number to work as a 203k contractor?

I do 203k renovations and have for over three years. A bank I've never worked for in the past is demanding my social security number before they will approve me to work for their borrower even though I'm not borrowing money from them. They say it's to see if there are any liens against me. I'm incorporated and have given them my federal ID number which is all the other banks require. Is this practice legal since this will expose me to identity theft?