New iPhone SMS Threat No Reason To Panic

You may have heard that researcher Charlie Miller has released details about a vulnerability that allows an attacker to take over an iPhone remotely with a SMS message. Now everyone is rushing to offer homegrown advice on how to fix the problem. But I'm going to offer a different point of view.Don't panic.

If you keep sensitive information on your iPhone, then take heart in knowing that it will be at least a few weeks until this attack is weaponized. If you don't keep sensitive data on your iPhone, then you are not likely to be the target of anyone's attack.

To understand why you shouldn't panic, let's look at the attack. A flaw in the iPhone software allows someone to remotely send SMS messages to your device that will trigger a buffer overflow, which will, in theory, give them access to your phone. To make this attack effective, much more research must be done, and several barriers must be overcome. But these barriers aren't going to be broken today or tomorrow. And an additional layer of security comes into play with wireless carriers being able to identify abuse on their networks and then blocking it.

A lot of the homegrown information about protection seems to revolve around two schools of thought: cancel your SMS plan or jailbreak your iPhone to stop certain software from running. Neither plan will provide any protection and will just inconvenience you more in the long run.

Canceling your SMS plan does no good because, unbeknown to you, your phone is constantly receiving SMS messages. These messages carry all kinds of information about the network and your phone's operating state, and they even alert you when you have received a voicemail. Disabling your SMS service just means you can't get messages from other people, but you will still get them from the system. Since this attack could allow someone to spoof a system message, you are still at risk.

Jailbreaking your iPhone is another theory. The thought behind this is that if you can stop MobileSMS from running, you are safe. But MobileSMS doesn't really do much besides read the messages from a database and display them. The CommCenter process is what reads the SMS messages from the network, parses them, and puts them in the database -- and this is where the major vulnerabilities are. If you stop this process from running on the phone, then the data portion of your iPhone will no longer work, basically turning your iPhone into a more expensive iPod Touch.

The only way to really be safe is to get the update from Apple when it becomes available.

Miller's Black Hat talk was about more than just a single vulnerability, though. It was a description of how to audit code previously thought to be safe from prying eyes. So although Apple may patch this one bug, you can be sure that more bugs are on the way and in more manufacturers' devices.

David Maynor is CTO of Errata Security. Special to Dark Reading