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iOS bug unlocks iPhones sans password

Making calls from locked iPhone 4s

A recently discovered bug in Apple's iOS 4.1 allows users to make iPhone calls without first entering a passcode.

The bug means there is no way to prevent unauthorized people from using the devices in the event they're lost or stolen. All that's required to unlock a phone is to press the Emergency Call button, enter a non-emergency number such as ###, tap the call button and immediately hit the lock button. Voila, the iPhone's contacts page will open, from which calls can be made.

Like most smartphones, the iPhone comes with a lock that requires a user to enter a password before calls and other features can be used. The ability to bypass the protection was reported on Friday by a MacForums user. Other members quickly confirmed it worked on iPhones running iOS 4.1 and that the technique also allowed unauthorized users to active the device's voice control mode.

You can test it for yourself, or view the video below to see it in action.

It's not the first time the iPhone passwords have been tripped up by a flaw involving the Emergency Call button. The Register was surprised to find just such a bug in August 2008. The embarrassing goof was quickly fixed, and we thought that would be the end of it. Now – for a limited time, anyway – it's back. ®

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