Check fraud rose nearly 400% in the U.S. last year, according to a Financial Crimes Enforcement Network report. And scammers are now using social media to promote a low-tech check scheme and post tips for other fraudsters. Wall Street Journal reporters Oyin Adedoyin and Justin Baer join host J.R. Whalen to discuss how it works and what you can do to protect your money.  Sign up for the WSJ's free Markets A.M. newsletter.  Learn more about your ad choices. Visit megaphone.fm/adchoices