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by John P. Mello, Jr.

German hackers crack Apple fingerprint technology

Sep 24, 20134 mins
Data and Information SecurityMobile SecurityPrivacy

Chaos Computer Club fools Touch ID on iPhone 5S

It didn’t take long for the hacking community to crack Apple’s fingerprint recognition system, Touch ID.

A German hacking group, Chaos Community Club, announced that they’d managed to fool the fingerprint scanner in the iPhone 5S with techniques generally used to defeat similar technologies in the market.

To crack Touch ID, CCC first photographed a fingerprint of a phone’s owner using a resolution of 2400 dots per inch. The image was then inverted and laser printed on a transparent sheet with the toner setting set to thick.

Next, pink latex milk or white wood glue was smeared into the print of the fingerprint. After the latex or glue dries, it’s lifted from the laser print, breathed on to moisten it slightly and placed on the iPhone’s fingerprint sensor to unlock the phone.

“In reality, Apple’s sensor has just a higher resolution compared to the sensors so far,” a CCC member, Starbug, explained in a statement. “So we only needed to ramp up the resolution of our fake.”

“As we have said now for more than years, fingerprints should not be used to secure anything,” added the hacker who performed the critical experiments that led to the successful circumvention of the fingerprint locking. “You leave them everywhere, and it is far too easy to make fake fingers out of lifted prints.”

Apple did not respond to a request for comment for this story.

While most security experts acknowledge that fingerprint scanners, in general, are no silver bullet for authentication, that doesn’t totally negate the value of using a fingerprint to secure a smartphone.

What the CCC did was more a proof of concept than a hack, contends Grayson Milbourne, security intelligence director at Webroot.

“They’ve proved that it’s possible to scan a fingerprint and use that to access the phone,” Grayson said in an email. “However, this is not a remote hack. They still need access to the user’s fingerprint and the phone itself.”

“It’s also worth noting that if Touch ID fails five times, it takes the user to a passcode option instead, bypassing the fingerprint scan entirely,” he continued.

“For consumers, Touch ID is still a great way to quickly access their phone,” he added.

[Also see: Apple’s iPhone 5S reopens debate on sensor data collection]

And that’s what Apple’s apparent intentions were when introducing Touch ID. “This is a consumer product,” Paul Henry, a security and forensic analyst with Lumension, said in an interview. “I don’t believe it was the intent of Apple to create a fingerprint reader that is so secure it’s going to stop a determined hacker.”

No one with critical business information on their phone should be depending solely on Touch ID to protect their phone, said Richard Henderson, a researcher with Fortiguard Labs. “As a target, it’s incredibly simple for someone to follow you around and wait for you to touch something,” he said.

“If you’re Tim Cook, and you’re walking around with an iPhone 5S right now with just Touch ID enabled, then you have an issue,” Henderson said. “I can guarantee you that I can pay a busboy at one of his favorite restaurants $100 and walk out of there with a glass he drank from.”

While cracking Touch ID may have been good research project, it may not be a cause of concern for many iPhone 5S owners because the amount of effort needed to mount the attack would be impractical for many hackers.

“It would be much easier to wait for the person to unlock their phone and then steal the phone or to attack their phone on a network through an OS vulnerability,” said Adam Ely, co-founder of Bluebox.

Even before Touch ID was cracked, byte tinkerers had discovered a way to skirt the lockscreen on Apple devices running the new version of its iOS mobile operating system. That vulnerability could be far worse for iPhone users.

“That’s because with those things anyone can pick up any random phone and get into it,” Michael Pearce, a security consultant with Neohapsis, said in an interview. “They don’t have to get a user’s fingerprint.”

“What’s interesting, though,” Pearce said, “is that Apple can put out a software patch that fixes the lockscreen. It can’t put out a patch to make fingerprints secure.”

BlueBox’s Ely discounts the security merits of Touch ID. “The fingerprint reader on the iPhone 5S is more of a convenience feature than a security feature, though it does provide additional security by preventing someone from watching you type in your pin code and replaying it,” he said.