In a new paper out of New York University's Tandon School of Engineering, researchers found that thousands of advertisers were able to run more than 357,000 political ads without disclosing who was behind them. The researchers, Laura Edelson, Tobias Lauinger and Damon McCoy, studied the company's Ad Library for more than a year, and found more than 68,000 pages bought more than $37 million worth of ads without fully disclosing who was behind them.

Though the group credits Facebook for making its advertising data available, they say its Ad Library is ultimately "easy to evade," and that "Facebook's ad platforms appear to have security vulnerabilities at several points." They recommend the company hire third-party auditors to keep tabs on the Ad Library.

"Our authorization and transparency measures have meaningfully changed since this research was conducted," a Facebook spokesperson said in a statement. "We offer more transparency into political and issue advertising than TV, radio or any other digital ad platform."