Ukrainian hackers reportedly used online quizzes to gain access to private Facebook user data and “inject unauthorized advertisements.”

According to CNN Business, the quizzes, like “What does your eye color say about you?,” were used to “take control of users’ internet browsers,” and gave the hackers “access to private information about Facebook users and their private friends’ lists.”

“Once users connected their Facebook and other social media accounts they were asked to install what Facebook described as ‘malicious browser extensions’ that essentially allowed the alleged hackers to pose as the affected users online,” reported CNN Business, which added that over “60,000 internet browsers used by Facebook users had been compromised.”

The hackers also reportedly used the quizzes to “inject unauthorized advertisements” in front of the users online.

User data which was accessed by the hackers included names, ages, pictures, and lists of friends.

“Friday, Facebook filed a complaint against two developers based in the Ukraine for violations of our policies and other US laws by operating malicious browser extensions designed to scrape Facebook and other social networking sites,” declared a Facebook spokesman in a statement. “By filing the complaint, we hope to reinforce that this kind of fraudulent activity is not tolerated on our services, and we will act forcefully to protect the integrity of our platform.”

Facebook has previously been accused of leaking user data through quiz apps.

In June, Breitbart News’ Lucas Nolan reported that the social network had been “accused of leaking the personal info of their users via a quiz app on their platform.”

The quiz application reportedly “left the personal data of Facebook users who have used the app unprotected on its website, leaving the info vulnerable to third parties who may wish to steal the info.”

Charlie Nash is a reporter for Breitbart Tech. You can follow him on Twitter, or like his page at Facebook.