Jailbreakers use zero-day PDF flaw to crack iPhone and iPad

A flaw in the way Apple's iOS handles PDF files is being used to allow iPhone and iPad owners to jailbreak their hardware, but security experts are warning that it could also offer a way in for hackers.

The JailbreakMe web site has released code that allows people to take control of their iOS devices without the need for a computer, simply by visiting the site.

The site was set up by Comex, a part of the iPhone Dev team that cracked the iPad in less than a day.

The software is designed to allow Apple users to install applications that aren't allowed by App Store administrators. Comex denied that the software causes a security problem.

"There's always a first time, but I think there's a good chance the security impact of these vulnerabilities will remain theoretical," the site's FAQ notes.

"Despite JailbreakMe being open sourced after an updated version of iOS was released, which would have made it relatively easy to modify the code into an attack, I didn't hear about any such modification except a proof of concept that showed up much later.

"The only iPhone virus ever to attack the general public was a trivial one that affected jailbreakers who installed OpenSSH (not installed by default) but left it at the default password."

A patch for the vulnerability is also available, and Comex points out that there is a useful purpose in being able to jailbreak a device without using a computer.

Apple chief executive Steve Jobs made much of the post-PC future in his WWDC keynote, but it is unlikely that this is what he had in mind.

Nevertheless, security experts are now warning that it is only a mater of time before hackers exploit the same vulnerability.

"A web site like JailBreakMe is making it easy to jailbreak your iPhone or iPad, but it could also be giving a blueprint to malicious hackers on how to infect such devices with malware," said Graham Cluley, senior technology correspondent for Sophos.

"I don't want to be a party pooper for those who wish to jailbreak their Apple devices, but it's essential that Apple closes this vulnerability as quickly as possible, before it is abused with malicious intent."

In response to the announcement, the German Federal Office for Information Security warned Apple users to be on their guard, and not to open PDF files from unknown sources.

"Possible scenarios for attacks by cyber criminals include the extraction of confidential information (passwords, online banking data, calendars, emails, SMS or contacts), accessing the device's cameras, the user's GPS data or listening in on phone conversations," the organisation said in a statement, Associated Press reports.