Miller, who cut his reverse-engineering teeth working for the National Security Agency, has been a prolific supplier of OS X and iOS exploits at events such as the Black Hat Security conference and the Pwn2Own hacker competition. He was the first known person to develop a working exploit that remotely took control of the iPhone. Less than a month after the Apple phone was released in 2007, he published a proof-of-concept webpage that secretly siphons SMS text messages, contact information, call history, and voicemail. Over the past five years, he has developed dozens of other exploits that target iOS and OS X. He has said he focused on Apple products because those are the devices he used most and he wanted them to be more secure.
More:
http://arstechnica.com/security/2012/09/serial-iphone-hacker-joins-twitter/
