(CNN) A pair of Ukrainian hackers used seemingly innocuous online quizzes and surveys, with titles like "What does your eye color say about you?," to gain access to private Facebook user data and to target users with "unauthorized" advertisements, the social media company says.

Facebook FB The alleged hackers improperly used afeature that helped them take control of users' internet browsers and gave them access to private information about Facebook users and their private friends' lists, Facebook alleged in a lawsuit filed in Northern California on Friday.

Working out of Kiev, Ukraine, Andrey Gorbachov and Gleb Sluchevsky allegedly lured Facebook users to connect their accounts to a range of online quiz apps with names like, "Do you have royal blood?, "You are yin. Who is your yang?" and "What kind of dog are you according to your zodiac sign?"

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.

Facebook offers a range of services that allow users to use their Facebook accounts to login to other services, including dating and music apps.

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