Though this will come as no surprise to anybody but a couple of researchers have found a method of attacking phones using the Simple Messaging Service (SMS):
A pair of security researchers from Germany demonstrated several techniques at the CanSecWest conference here Wednesday that enable them to remotely reboot, shut down or even completely disable many popular mobile phones with SMS messages.
It should be noted that they’ve only test this on feature phones so we don’t know if smartphones will be affected or not. Likewise they only tested this on GSM phones so it may be such a thing where most CDMA phones will remain unaffected. Either way if you want to screw with somebody and you know their number this would certainly be a viable method. Heck if you knew somebody’s number you could potentially start a denial of service attack against their phone by constantly sending crafted text messages that cause your target’s phone to reboot.