http://www.techradar.com/news/equifax-data-breach-how-to-tell-if-youre-one-of-the-143-million-users-affected

Credit reporting firm Equifax revealed today that hackers gained unauthorized access to personal information for up to 143 million US consumers  — more than a third of the country's population.

According to Equifax's investigation, the breach occurred around mid-May through July of this year, exploiting a website application vulnerability.