A MacRumors reader has identified a security flaw in iOS 4.1 that would allow users to bypass the iPhone lock screen. Attempting to place an emergency call to a non-emergency number and immediately pressing the sleep/wake button on the iPhone will open the Phone app, allowing the user to access contacts, call history, voicemail and call any number.
The user will not be able to leave the Phone application and access other data on the device, and must either reboot the device or place and end another call to return to the normal lock screen. iLounge has confirmed that this issue exists in iOS 4.1 on all models of iPhone and have also received reports that the problem exists in at least some versions of iOS 4.0.
Notably, John Gruber reports that the problem does not exist in iOS 4.2 beta 3, suggesting that Apple may have already identified and fixed the security flaw. Note that this issue does not affect the iPod touch as it has no Emergency Call feature.
