This bug first appeared in iOS 2.0; given a password protected iPhone, when the right buttons were pushed in the correct sequence (actually all you had to do was to hit the Emergency Call button and after that double click Home), you could easily access call logs, voicemails, contacts etc. The bug was fixed by Apple with a software update, but it resurfaced in iOS 4.1.
The “unlocking” method this time was a bit more complex, yet a potential hacker could easily get access to your “password protected” iPhone just by dialing an emergency number and then pressing the home button.
Now again the same bug has appeared in iOS 6.1 that allows a persistent hacker to gain access to all your personal data from an iPhone which is passcode locked. Apple has acknowledged the bug and has assured that the fix is on the way. Trudy Muller, the spokesperson for Apple declared Thursday afternoon in an interview: "Apple takes user security very seriously .We are aware of this issue, and will deliver a fix in a future software update."