How the FBI Managed To Get Into the San Bernardino Shooter’s iPhone

A new report from The Washington Post reveals how the FBI gained access to an iPhone linked to the 2015 San Bernardino shooting. Apple refused to build a backdoor into the phone, citing the potential to undermine the security of hundreds of millions of Apple users, which kicked off a legal battle that only ended after the FBI successfully hacked the phone. Thanks to the Washington Post’s report, we now know the methods the FBI used to get into the iPhone. Mitchell Clark summarizes the key findings via The Verge: The phone at the center of the fight was seized after its owner, Syed Rizwan Farook, perpetrated an attack that killed 14 people. The FBI attempted to get into the phone but was unable to due to the iOS 9 feature that would erase the phone after a certain number of failed password attempts. Apple attempted to help the FBI in other ways but refused to build a passcode bypass system for the bureau, saying that such a backdoor would permanently decrease the security of its phones. After the FBI announced that it had gained access to the phone, there were concerns that Apple’s security could have been deeply compromised. But according to The Washington Post, the exploit was simple: [An Australian security firm called Azimuth Security] basically found a way to guess the passcode as many times as it wanted without erasing the phone, allowing the bureau to get into the phone in a matter of hours.

The technical details of how the auto-erase feature was bypassed are fascinating. The actual hacking was reportedly done by two Azimuth employees who gained access to the phone by exploiting a vulnerability in an upstream software module written by Mozilla. That code was reportedly used by Apple in iPhones to enable the use of accessories with the Lightning port. Once the hackers gained initial access, they were able to chain together two more exploits, which gave them full control over the main processor, allowing them to run their own code. After they had this power, they were able to write and test software that guessed every passcode combination, ignoring any other systems that would lock out or erase the phone. The exploit chain, from Lightning port to processor control, was named Condor. As with many exploits, though, it didn’t last long. Mozilla reportedly fixed the Lightning port exploit a month or two later as part of a standard update, which was then adopted by the companies using the code, including Apple.