Researcher finds iPhone flaw

Famed Mac hacker Charlie Miller has found a possible flaw in Apple's iPhone - although it's not going to be easy to exploit.

Miller, a principal security analyst at Independent Security Evaluators, is known for his prowess in hacking Apple products, winning the CanSecWest security conference in 2008 and 2009.

Miller detailed his latest find at the Black Hat Europe security conference. The finding refutes what was a commonly held belief about how an unmodified iPhone works.

Most security researchers thought it wasn't possible to run shellcode on an iPhone. Shellcode is code that can run from a command line, but the iPhone was thought not to allow it for security reasons.

The ability to run shellcode is important, as it would let a hacker do all sorts of malicious actions, such as peeping at a person's text messages or call history of an iPhone from a remote location.

Earlier versions of the iPhone software didn't have any protection to prevent people from tampering with its memory to run other commands, Miller said. But the latest version of the iPhone's software strengthened the overall security of the phone, Miller said.

Miller said he's found a way to trick the iPhone into running code that enables shellcode. To run shellcode on an iPhone, however, an attacker would first need a working exploit for an iPhone, or a way to target some software vulnerability in, for example, the Safari Web browser or the mobile's operating system. Miller said he doesn't have one now.

But if someone did "this would allow you to run whatever code you want," Miller said in an interview after his presentation.

In 2007 Miller and some of his colleagues did find a vulnerability in mobile Safari that would allow an attacker to control the iPhone. Apple was immediately notified and later issued a patch for the problem.

The significance of Miller's find is that it works with unaltered versions of the iPhone as the devices are sold in stores. Researchers have shown a greater ability to manipulate iPhones that are "jailbroken," the term for phones that have been modified to allow installation of applications not vetted by Apple. Those jailbroken phones have less protection on the device's memory, Miller said.

Miller said he wasn't sure whether Apple was aware of the latest issue. Miller stopped short of calling the problem a vulnerability, saying instead that Apple engineers may have overlooked the issue. Apple also has never come out publicly and said it is impossible to run shellcode on an iPhone, he said.