Book Image

Fuzzing Against the Machine

By : Antonio Nappa, Eduardo Blázquez
Book Image

Fuzzing Against the Machine

By: Antonio Nappa, Eduardo Blázquez

Overview of this book

Emulation and fuzzing are among the many techniques that can be used to improve cybersecurity; however, utilizing these efficiently can be tricky. Fuzzing Against the Machine is your hands-on guide to understanding how these powerful tools and techniques work. Using a variety of real-world use cases and practical examples, this book helps you grasp the fundamental concepts of fuzzing and emulation along with advanced vulnerability research, providing you with the tools and skills needed to find security flaws in your software. The book begins by introducing you to two open source fuzzer engines: QEMU, which allows you to run software for whatever architecture you can think of, and American fuzzy lop (AFL) and its improved version AFL++. You’ll learn to combine these powerful tools to create your own emulation and fuzzing environment and then use it to discover vulnerabilities in various systems, such as iOS, Android, and Samsung's Mobile Baseband software, Shannon. After reading the introductions and setting up your environment, you’ll be able to dive into whichever chapter you want, although the topics gradually become more advanced as the book progresses. By the end of this book, you’ll have gained the skills, knowledge, and practice required to find flaws in any firmware by emulating and fuzzing it with QEMU and several fuzzing engines.
Table of Contents (18 chapters)
Part 1: Foundations
Part 2: Emulation and Fuzzing
Part 3: Advanced Concepts
Chapter 12: Conclusion and Final Remarks

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...