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

Building the firmware

As mentioned before, we will download the latest version of OpenWrt and build it for x86. On a modern Ubuntu/Debian distribution, you just need to follow these steps:

  1. Prepare the build environment:
    sudo apt update
    sudo apt install build-essential clang flex g++ gawk gcc-multilib gettext git libncurses5-dev libssl-dev python3-distutils rsync unzip zlib1g-dev
  2. Check out the most recent version of the firmware:
    git clone  --depth 1 --branch v21.02.3
    cd openwrt
  3. Update the feeds:
    /scripts/feeds update -a
    /scripts/feeds install -a
  4. Configure the firmware image and the kernel:
    make menuconfig #here you can select cross compilation to other hardware if you'd like
    make -j $(nproc) kernel_menuconfig
    # Build the firmware image
    make -j $(nproc) defconfig download clean world #the -j parallelize compilation for your CPU

The make menuconfig command will allow us to select the target hardware that we prefer...