Quote:Last month's Facebook hack affected about 50 million Facebook accounts according to Facebook's official announcement on September 28, 2018.

Hackers exploited a series of bugs in Facebook's "View as" function that allows users of the site to view their profiles as public users. The function is handy as it allows users to determine what regular visitors to the profile page see to adjust the visibility of information accordingly.

The hackers gained access to "access tokens" which are used by Facebook and other authentication systems to determine whether the user is allowed to access certain content on the site.

That meant that the hackers did not gain access to user passwords and that it was trivial to shut them out.

Facebook disabled the feature after the hack and invalidated the method used by the hackers to gain access to account data.

Full reading: https://www.ghacks.net/2018/10/14/find-out-if-you-have-been-affected-by-the-recent-facebook-hack/