Many securities are used to prevent people from access to private information, and while the majority of them are only as secure as the user allows, there isn't always an airtight solution. There have been major exploits regarding the Galaxy Note 2 in the past, which abused a bug in the Exynos processor in order to gain access to your entire phone.
While that exploit was fixed with an update, that update came with a very slight, almost imperceivable problem. This morning, Terence Eden made a discovery by looking at the Emergency Dialer on the Samsung phablet, when he noticed a flaw which allows one to temporarily gain access past the Note 2's lockscreen.
So far, this has only been tested on the Galaxy Note 2 (N7100), running the UK version of the TouchWiz skinned Android 4.1.2 Jelly Bean. The minor shortcoming in security is said to be exploited by a series of steps, starting off with a screen locked and secured using PIN, pattern, password, and/or facial recognition.
Once the phone is locked using one of the aforementioned security features, you would start by tapping the "Emergency Call" button, then tap the ICE icon on the bottom left side of the screen. Once in that screen, you hold down the menu button and release, which will cause the home screen to be exposed for a just a slight second.
That slight second could be long enough to tap on an icon, or a widget in your home screen, or get a glance personal emails if you have that widget displayed. Tapping an application that performs an action beyond opening will execute its function, so with a direct dial shortcut on your home screen, one could easily tap that in order to make a call to whoever's number the direct dial is set to. Depending on which launcher you use, tapping the home button multiple times would allow one to have a glance at all of your homescreens. When opening apps that only load a splash page though, such as Google Play, it will revert back to the lockscreen as it should.
So yes, this is a very minute flaw, but caution should always be exercised in case someone picks up your phone. Along with caution, there are other ways to protect your information from this exploit. One would be to minimize the use of direct dial shortcuts and widgets on your home screen, or at least ones that display personal information.
Using a third party launcher or lockscreen won't be enough to protect your phone from this exploit, but if you want to still keep your icons on your homescreen, then using an app locker that requires a password upon opening an app will be the safest bet along with common sense. As for encrypting your device, Terence Eden told me in an email that he has tested this exploit on an encrypted Galaxy S3, which did NOT appear to work, but has also said that it was not tested exhaustively.
A very interesting find if you ask me, and kudos for the discovery! Would it be enough to motivate someone to go out and start hacking phones? Not likely. But it's nice to know these things in case you end up having to protect yourself from someone who may have malicious intent.