A piece of code has been discovered in the iPhone operating system …

Jonathan Zdrianski, author of the book iPhone Open Application Development, discovered a URL hidden in iPhone’s CoreLocation that he believes the iPhone uses to check whether any apps on your phone match with those listed in a database of blacklisted applications. That may allow Apple to remotely de-authorize those programs, or perhaps even delete them.

“This suggests that the iPhone calls home once in a while to find out what applications it should turn off,” Zdrianski wrote. “At the moment, no apps have been blacklisted, but by all appearances, this has been added to disable applications that the user has already downloaded and paid for, if Apple so chooses to shut it down.”

Apple CEO Steve Jobs told the Wall Street Journal that it is indeed possible for Apple to reach into your phone from afar and disable malicious applications.

“Hopefully we never have to pull that lever, but we would be irresponsible not to have a lever like that to pull.”