First iPhone worm hits Jailbroken iPhones in Australia

First iPhone worm discovered! Jailbroken iPhones in Australia have been infected by a worm (written by a hacker calling themselves "ikex") that has changed their wallpaper to an image of 1980s pop crooner Rick Astley. The worm affects users who have jailbroken their iPhones and installed SSH without then changing the default password and is currently a harmless exploit that simply changes the user's iPhone background to an image of singer Rick Astley, but could be used for much more malicious purposes.

If you have jailbroken your iPhone or iPod Touch, and installed SSH, then you must always change your root user password to something different than the default, "alpine". In fact, it would be a good idea if you didn't use a dictionary word at all.

The worm will not affect users who have not jailbroken their iPhones or who have not installed SSH.

(source)