Here’s how the FBI managed to get into the San Bernardino shooter’s iPhone

The FBI partnered with an Australian security firm called Azimuth Security to gain access to an iPhone linked to the 2015 San Bernardino shooting, a new report from The Washington Post reveals. Before now, the methods the FBI used to get into the iPhone were kept secret. It was only clear that Apple wasn’t involved, as the company had refused to build a backdoor into the phone, kicking off a legal battle that only ended after the FBI successfully hacked the phone.

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: Azimuth 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.