A new worm, called the iPhone/Privacy.A worm, connects to jailbroken iPhones running SSH with the default password and takes a “treasure trove” of data including email, SMS messages, photos, music files, and everything else on your phone. It then kills your dog.
OK, the last part was a joke but come on. If you jailbreak your phone, change your password. Real simple. You can follow these directions or simply SSH into your iPhone and type “passwd” and enter a new password. Easy peasy.