iPhone 4 security flaw means strangers can access phone functions without knowing user's password.

An iPhone security flaw allowing users to access the keyboard without knowing the handset's password has been posted online A security flaw has been found in Apple's latest iPhone which allows strangers to bypass the handset's passcode-protected lock screen with a few button presses.
Most users set up a password to prevent others from accessing the phone's contents, but a Brazilian man posted a video of himself on the internet showing a quick way of getting around it. He taps the “emergency call” button, then enters three # signs, taps the green call button and immediately presses the button on the top of the phone that locks the screen.
That simple procedure gives access to the phone app, which contains the address book, voicemail and call history – but it does not allow access to texts, emails or any other iPhone apps. The Guardian tried out the procedure with success on an iPhone 4 running iOS 4.1, the latest version of Apple's mobile operating system.
The iPhone is one of the best-selling handsets on the market, but security researchers have criticized its weak security. A similar flaw discovered on the iPhone in 2008 allowed people to easily bypass the lock screen to access mail, contacts and bookmarks. Apple acknowledged the bug and issued a software patch.
In August this year the German government warned that several Apple devices including the iPhone and iPad had two critical security weaknesses, and advised users not to open PDF files or access unfamiliar websites until Apple released a fix.
(Source: Guardian. Co.uk)