Technology and media company Yahoo has confirmed that a major set of data was stolen from within the company’s network in 2014. The data includes personal information of at least 500 million users.

An internal investigation conducted by Yahoo Inc. confirmed that a major data leak was performed by what the company called a “state-sponsored actor.”

In late 2014, a large data set containing names, email addresses, telephone numbers, dates of birth, hashed passwords and even the encrypted or unencrypted security questions and answers of 500 million users was stolen from the company’s network. According to Yahoo, the stolen information did not include unprotected passwords, payment card data, or bank account information. The company is cooperating with law enforcement on the issue.