Security Flaws in Android 4.0 (ICS)
Facial reorganization to unlock can easily be bypassed with simple photo trick in Android 4.0 (Ice Cream Sandwich). Recently a blogger named "soyacincau" demonstrated about he vulnerability and showed how easily any one can bypass the facial reorganization. He took a photo of himself using another phone and held it up to the front facing camera on the Samsung Galaxy Nexus, the first smartphone to run Android 4.0, which was then unlocked. In ocotober a developer of CyanogenMod also concluded the same thing.
Later A Google spokesperson told that the feature is considered to be experimental and offers little security. According to the news site, the user interface for the Face Unlock feature also warns users that it is less secure than using a pattern, PIN or password, even going as far as saying "Someone who looks similar to you could unlock your phone". It is unclear if Google will add "Or a photograph of you" to the warning.