The Touch ID fingerprint sensor in the iPhone 5s has already been hacked—well, kind of. Over the weekend, a hacking team called the Chaos Computer Club (CCC) published a way to bypass Touch ID by replicating a lifted fingerprint.
Apple calls Touch ID “the most advanced hardware or software we’ve put in any device,” and the company believes the technology is the perfect replacement for a passcode. CCC disagrees.
“In reality, Apple’s sensor has just a higher resolution compared to the sensors so far. So we only needed to ramp up the resolution of our fake”, said the hacker with the nickname Starbug, who performed the critical experiments that led to the successful circumvention of the fingerprint locking. “As we have said now for more than years, fingerprints should not be used to secure anything. You leave them everywhere, and it is far too easy to make fake fingers out of lifted prints.”
What CCC had to do to bypass Touch ID is essentially create a fake finger out of latex.
First, the fingerprint of the enroled user is photographed with 2400 dpi resolution. The resulting image is then cleaned up, inverted and laser printed with 1200 dpi onto transparent sheet with a thick toner setting. Finally, pink latex milk or white woodglue is smeared into the pattern created by the toner onto the transparent sheet. After it cures, the thin latex sheet is lifted from the sheet, breathed on to make it a tiny bit moist and then placed onto the sensor to unlock the phone. This process has been used with minor refinements and variations against the vast majority of fingerprint sensors on the market.
CCC positions its discovery as evidence that Apple’s Touch ID isn’t a better alternative to a 4-digit pin. Senator Al Franken recently voiced similar concerns in an open letter to the company. Apple’s argument is that the majority of iPhone users don’t put any passcodes on their iPhones to begin with, so Touch ID is intended to encourage security.
Sure, an elaborate process could theoretically be used to lift your fingerprint and get into your iPhone (assuming there’s physical access to your fingerprint and iPhone to begin with). But does that make it less secure than cracking a 4-digit pin? If someone is willing to go through this process to get into your iPhone, you’ve probably got bigger security issues to worry about.