Installing an untrusted app on your Apple, iPhone and iPad could cause you great damage through data theft, the United States government warns. National Cybersecurity and Communications Integration Center, and the U.S. Computer Emergency Readiness Teams said so in an online bulletin it issued. They identified a technique known as the 'Masque Attack,' as the culprit software hackers use to exploit the vulnerability in iOS to steal sensitive data. Login credentials and access sensitive data are used by hackers to remotely monitor activity on bugged devices. The agencies advised users to click on 'Don't Trust' whenever iOS flashes a warning that says 'Untrusted App Developer. Users are also warned not to click on “install” from pop-ups when surfing the web and rather should download apps only from Apple apps store.