Apple’s Core iOS Source Code Leaked on GitHub, Could Reinvigorate Jailbreaking

Apple is notorious for keeping its source code close to its chest, but someone just leaked a heap of very sensitive code online. A user known as “q3hardcore” posted large segments of Apple’s secure iBoot code to GitHub. The company issued a DMCA takedown request, but the code is out there in the wild now. This could lead to new attacks and vulnerabilities for iOS, but jailbreaking might also come back.

The iBoot framework is a low-level piece of software on all Apple hardware running iOS — on other devices, you’d call this the bootloader or the BIOS. It’s the first thing that starts up when the phone is turned on, because it loads the kernel and verifies that it was signed by Apple. Attempting to boot a modified kernel will immediately throw up a red flag in iBoot. Apple considers this code so integral to its security model that it offers a $200,000 bug bounty for vulnerabilities.

This code is from iOS 9, circa 2014. However, security researchers suspect that much of the code is still active in iOS 10. A handful of key files are missing, so it cannot be compiled. However, security researcher Jonathan Levin confirms the code is the real deal as it matches some iBoot code he himself has reverse engineered. Apple’s quick DMCA filing also strongly suggests the leak is real.

Flaws in older versions of iBoot have been leveraged by hackers to compromise the iPhone’s security, but users have also relied on the vulnerabilities for jailbreaking. That’s the equivalent of getting root access on an Android phone. Apple’s use of the Secure Enclave processor in newer iPhones has effectively killed the jailbreaking community. It takes a lot of time and expertise to uncover vulnerabilities, and they’re highly prized by security firms. These days, modders are more likely to sell the exploit than release it for free to the jailbreak community. This source code leak could change all that, though.

Security researchers and jailbreak developers are no doubt pouring over the iBoot code. Levin suggests that so-called “tethered” jailbreaks that require connecting the phone to a computer could become a reality again soon. These relatively simple jailbreaks have been blocked for several years by the Secure Enclave. However, it’s important to remember these jailbreaks are security holes that someone could use to steal data or damage your device. Apple is probably going to be working overtime for the foreseeable future to deal with the fallout from this leak.