The Prototype iPhones That Hackers Use to Research Most Sensitive Code of Apple

Motherboard
Mathew Solnik stood next to two of the best iPhone hackers in the world and addressed the question the hundreds of people watching him were all wondering.
“The white elephant in the room: How exactly did we get it?” Solnik, a well-known security researcher, said as he wrapped up one of the most anticipated talks at the Black Hat security conference in Las Vegas in early August 2016. In attendance, among hundreds of security professionals and hackers, were researchers from a company that sells iPhone-cracking services to cops around the world, and Apple’s own employees.
The thing that his team had been able to analyze for the first time was the iPhone’s Secure Enclave Processor (SEP), which handles data encryption for the iPhone. How they were able to do this was a valid question given Apple’s notorious secrecy, and the fact that the SEP is one of the most important and most closely guarded components of the iPhone, the most secure smartphone on the market.
“Well, you get to ask us next time we talk,” Solnik added. (Solnik said the same when I approached him after the talk.)
There was no next time: The team has never publicly discussed its methods.
Now, more than two years later, Motherboard has learned how the team did it. During our investigation, we also discovered how other iPhone hackers research the most secure components and processes of the device.
Solnik’s team used a “dev-fused” iPhone, which was created for internal use at Apple, to extract and study the sensitive SEP software, according to four sources with specific knowledge of how the research was done. Dev-fused devices are sometimes called prototypes in the security research industry. They are essentially phones that have not finished the production process, or have been reverted to a development state.
In other words, they are pre-jailbroken devices.
These rare iPhones have many security features disabled, allowing researchers to probe them much more easily than the iPhones you can buy at a store. Since the Black Hat talk, dev-fused iPhones have become a tool that security researchers around the world use to find previously unknown iPhone vulnerabilities (known as zero days), Motherboard has learned.
Dev-fused iPhones that were never intended to escape Apple’s production pipeline have made their way to the gray market, where smugglers and middlemen sell them for thousands of dollars to hackers and security researchers. Using the information gleaned from probing a dev-fused device, researchers can sometimes parlay what they’ve learned into developing a hack for the normal iPhones hundreds of millions of people own.
During Motherboard’s months-long investigation, I spoke to two dozen sources—security researchers, current and former Apple employees, rare phone collectors, and members of the iPhone jailbreaking scene—about the underground trade of dev-fused iPhones and their use in the iPhone hacking community. I used one of these devices and obtained “root” access on it, giving me almost total control over the phone; gaining root access allows researchers to probe many of the phone’s most important processes and components. And I learned that these devices are used by some of the highest-profile companies and independent experts that research and hack iOS to find valuable bugs that may later be exploited by governments and law enforcement agencies.
At BlackHat, Solnik and his two former colleagues David Wang and Tarjei Mandt—also known as Planetbeing and Kernelpool in the iPhone jailbreaking community—blew the doors off the SEP with the impressive and technical talk, which delved into, for example, how the phone’s application processor and SEP communicate using a “secure mailbox,” the SEP’s “bootflow,” and the specific “opcodes” that Apple uses to read information from the processor.
For iPhone hackers, the presentation was a godsend. At the time, Patrick Gray, who hosts an influential infosec podcast, described it as a “how2pwn guide” for the SEP, and thus, the iPhone.
One reason the iPhone is so hard to hack is that Apple makes it almost impossible to study how the SEP and other key components work. That’s because the SEP operating system is encrypted, and—in theory—cannot be extracted or reverse engineered from a regular iPhone. But from a dev-fused device it’s possible, and has been repeated since Solnik’s talk by other researchers.
“Wish I could say that they succeeded in pwning the system, but like many in the field [Solnik’s team] leveraged specific prototypes,” an iPhone jailbreaker who asked to be identified as Panaetius told Motherboard. Panaetius did not want to be identified given that he has also used dev-fused devices and is worried Apple may go after him.
A person who formerly worked in Apple’s security team told Motherboard that he approached Wang after the talk at the conference. When he asked Wang how they managed to study the SEP, Wang told him that “Solnik got a dev-phone and dumped the firmware through standard Apple tools.”
An independent iOS security researcher, who spoke on condition of anonymity in order not to damage his reputation within the jailbreaking community, said “Solnik was full of dev-fused [iPhones],” at the time of the SEP talk.
Another iOS security researcher, who also asked not to be identified, said he saw Solnik’s dev-fused devices and the proprietary cables used to work on them in the lead up to the SEP talk at Black Hat.
Solnik, Wang, and Mandt, did not respond to multiple requests for comment. (At the time of the talk, Wang and Mandt were working for Azimuth, an Australian company that provides top-end hacking tools to governments such as the USA, Canada and the UK. Solnik had just left Azimuth.) Solnik was the subject of an episode of Phreaked Out, Motherboard’s 2014 documentary series about hacking.
At the time, they may have been the first ones to get to the SEP, but thanks to the proliferation of dev-fused iPhones, others have repeated their feat. Lisa Braun, a pseudonymous independent iOS researcher, recently claimed to have dumped the SEP from an iPad Air 2 prototype.
And he is not the only one.
According to five sources in the iPhone hacking world, Cellebrite, a forensic firm that sells devices that can unlock iPhones, has purchased and used dev-fused devices to develop its products. Cellebrite did not respond to a request for comment.
Chris Wade, the cofounder of Corellium, a startup that sells a product that allows users to create virtual instances of almost any iOS device in the world, has also gotten his hands on these devices, according to three sources in the iPhone hacking world and three sellers.
Wade, who is known as cmw in the jailbreaking community, told Motherboard he has never purchased a dev-fused device. He admitted having “played” with them at a conference, but denied using them in the development of Corellium. (In a 2016 tweet, however, Wade joked about owning “iPhone prototypes.”)
“I want to be 100 percent clear we didn’t/don’t use dev phones @ Corellium. We don’t buy stolen Apple stuff!” Wade told Motherboard in an online chat. “I spent years working on Corellium and we never needed them. Using stolen dev phones is 100 percent the best way to get Apple to sue you or just fuck your life up.”
Before Solnik’s Black Hat talk, Apple had yet to provide decrypted kernels to the public. Analyzing the kernel is a key step to hacking the iPhone and to understanding how iOS really works under the hood. And these dev-fused iPhones, available on the gray market for four or five figures, are the perfect tool to do that.
Other researchers in the community told Motherboard that dev-fused devices are widely used in the iPhone hacking scene by researchers looking for zero day vulnerabilities.
As Mandt put it in a Tweet in July of 2017, “anyone with a bit of effort and money can get hold of a switchboard device.” (“Switchboard devices” are another term for some dev-fused phones, which refers to the proprietary operating system they run.)
While the devices are indeed rare, if you go looking for them, they’re not hard to find.