Several phone apps are sending sensitive user data, including health information, to Facebook without users' consent, according to a report by The Wall Street Journal. An analytics tool called "App Events" allows app developers to record user activity and report it back to Facebook, even if the user isn't on Facebook, according to the report .
One example detailed by the Journal shows how a woman would track her period and ovulation using an app from Flo Health. After she enters when she last had her period, Facebook software in the app would send along data, such as whether the user may be ovulating. The Journal's testing found that the data was sent with an advertising ID that can be matched to a device or profile.
Although Facebook's terms instruct app developers not to send such sensitive information, Facebook appeared to be accepting such data without telling the developers to stop. Developers are able to use such data to target their own users while on Facebook.