Apple plugs critical iPhone jailbreak holes

Computerworld - Apple today patched the two vulnerabilities used to jailbreak Apple's newest iOS 4 operating system, bugs that security researchers warned could be used to hijack iPhones, iPod Touches or iPads.

The patches came just 10 days after a group published a site that automatically exploited and then jailbroke any iOS 4 device that used the mobile Safari browser to surf to jailbreakme.com.

Last week, one prominent iPhone vulnerability researcher called the exploit -- which was actually a two-stage hack -- both "sweet" and "scary."

Also last week, other researchers confirmed that the first exploit of the pair leveraged a flaw in Safari's parsing of fonts in PDF documents to compromise the browser. A second vulnerability was exploited to break out of the isolating "sandbox" and gain full, or "root," control of the device.

Today, Apple identified both bugs.

"A stack buffer overflow exists in FreeType's handling of CFF [Compact Font Format] opcodes," Apple's advisory said. "Viewing a PDF document with maliciously crafted embedded fonts may allow arbitrary code execution."

FreeType is an open-source font engine that Apple uses as a component in both its Mac OS X desktop operating system and in iOS on its mobile devices.

The vulnerability used by jailbreak.com to gain root access to iPhones was in IOSurface, a code framework available to developers in both iOS and Mac OS X, Apple said. "Malicious code running as the user may gain system privileges," the advisory read.

Apple issued a separate update for the iPad because the tablet still runs a predecessor of iOS 4.

According to the Apple advisory, the update does not apply to 2007's first-generation iPhone, but only to the iPhone 3G or later running iOS 2.0 or later.

Nor is Apple apparently patching either of the vulnerabilities in Mac OS X, or even acknowledging whether they exist in the desktop operating system. "Apple no patchy os x. Is it not vulnerable or do they only care in stopping jailbreaking?" tweeted Charlie Miller Wednesday.

A well-known security researcher with a reputation for hacking Macs and iPhones, Miller called the jailbreaking two-stage exploit "beautiful work" last week.

Today's patches weren't a surprise.

Earlier this week, security blogger Ryan Naraine reported that sources had told him Apple was going to ship an iOS update this week. And last Friday, the FreeType patched the CFF bug in its source tree, which would have given Apple the necessary source code to craft their update.

Users can download the iOS update by connecting their iPhone, iPod Touch or iPad to their PC or Mac, running iTunes, clicking on the device in the listing on the left and then clicking the "Check for Update" button.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer or subscribe to Gregg's RSS feed . His e-mail address is gkeizer@ix.netcom.com.

Read more about Security in Computerworld's Security Topic Center.