Social applications linked to Facebook can track you and your friends' whole life.
Privacy protection company Secure.me analyzed some 500,000 Facebook apps and revealed some shocking facts.
According to the Sydney Morning Herald, Secure.me said that 63 percent of those apps ask for the ability to post on your behalf, whereas 69 percent of them can get your email address.
"It has become second nature to connect various apps like Instagram, SocialCam, AngryBirds, CityVille, and Spotify to your Facebook ID," Secure.me founder Christian Sigl said.
"You just click 'agree' without even really knowing what you are agreeing to. What you don't realise is that social apps linked to your Facebook profile can pretty much track your and your friends' whole life," Sigl added.
"It doesn't matter what your privacy settings are, the apps still get this information," he added.
The report said that after taking information from a user's account, the app makers not only can effectively hack your Timeline and sell your email address to any unscrupulous buyer, they can also potentially well steal your identity.
Some 30 percent of those apps know their users' birthdates, which would in theory allow them to uncover their social security numbers.
According to the report, the analysis revealed that the permission puts your friends at risk, too.
According to Secure.me, 21 percent of apps, one in every five, can access the personal data of the user's friends, including friends' birthdays, education and work history.
Some 12 percent of the apps can grab your location information at will, the report added.