New York Attorney General Eric Schneiderman's office opened up an investigation Friday into the major consumer credit reporting agency Equifax, which may have compromised the information of 143 million Americans, including 8 million New Yorkers.

Schneiderman's office sent a letter to Atlanta-based Equifax seeking more information about the data breach that lasted from mid-May through July. During the attack, intruders got unauthorized access to consumers' names, Social Security numbers, birthdays, addresses and driver's license numbers. According to the Federal Trade Commission, hackers took 209,000 individuals' credit card numbers and dispute documents for 182,000 people, as well as personal information on some individuals in the U.K. and Canada.

“The Equifax breach has potentially exposed sensitive personal information of nearly everyone with a credit report, and my office intends to get to the bottom of how and why this massive hack occurred,” Schneiderman said in a statement. “I encourage all New Yorkers to immediately call Equifax to see if their data was compromised and to consider additional measures to protect themselves.”