All mortgage lenders are susceptible to money launderers and mortgage fraud. The companies are not corrupt but an employee with them or with a bank doing business with them can use them to launder money. If the company carelessly accepts money or property in a loan scheme, they may be an accessory to a crime.
This blog outlines some cases:
http://www.mortgagefraudblog.com

The blog is provided by a company which provides fraud services for the mortgage industry.