Setting up an iOS emulator

We will use a research version of iOS 14 that has a kernel full of useful symbols. We have decided not to use iOS 16 to avoid conflicts with stakeholders and the community, because providing an already fully functional fuzzer for iOS 16 (the latest version at the time of writing) did not seem ethical to us. In this section, we will follow various steps to prepare our boot image and fuzz a good part of the syscalls and not only the socket() syscalls, as originally done by Trung to reproduce the SockPuppet vulnerability. We have been in contact with Trung to establish a reliable baseline for presenting his fork of QEMU.

There are two ways to prepare a bootable image. The first is a type of boot that doesn’t have a backend filesystem; it’s a minimal ramdisk booted in RAM. Hence, no restore is performed of the original iOS filesystem. To obtain the restore (the second way), you are required to generate a fake system restore ticket to obtain a...