Hackers found an iOS 6 bug two weeks ago that allowed thieves into your phone, but only the Phone app and the features contained within could be accessed. Just after that, recently another screen lock bypass vulnerability reported in iOS 6.1 by researchers. This vulnerability allows users to bypass the lock screen pass code and access the phones photos and contacts. Researchers say the vulnerable device can be plugged into a computer via USB and access data like voice mails, pictures, contacts, etc. The file system of iOS is in encrypted form.
Source: https://thehackernews.com/2013/02/how-to-bypass-ios-612-screen-lock.html