the 7z rabbit hole is extremely deep. (1000's of crashes)

Introduction

This tutorial explores the fascinating world of the 7z codebase and software fuzzing, inspired by the insights gained from the video "the 7z rabbit hole is extremely deep." By following this guide, you will learn about the 7z compression software, its vulnerabilities, and how software fuzzing can help improve security. This knowledge is relevant for software developers, security researchers, and anyone interested in coding or software testing.

Step 1: Understanding the 7z Codebase

• Learn about 7z: 7z is an open-source file archiver with a high compression ratio. Familiarize yourself with its features and how it compares to other archiving tools.
• Access the source code: You can find the 7z codebase on its official repository. Download and review the code to understand its structure and functionality.
• Key components to focus on:
  • Compression algorithms
  • File format handling
  • Error handling mechanisms

Step 2: Introduction to Software Fuzzing

• What is fuzzing: Software fuzzing is a testing technique used to discover vulnerabilities by sending random or unexpected inputs to a program.
• Benefits of fuzzing:
  • Identifies crashes and bugs
  • Helps improve security by exposing vulnerabilities
• Common fuzzing tools: Explore popular fuzzing tools such as AFL (American Fuzzy Lop) and libFuzzer to understand how they work.

Step 3: Setting Up Your Fuzzing Environment

• Install necessary tools:
  • Ensure you have a suitable programming environment set up (C/C++ compiler, build tools).
  • Download and install fuzzing tools (AFL, libFuzzer).
• Build the 7z project for fuzzing:
  • Clone the 7z repository.
  • Modify the build configuration to include fuzzing support.
  • Compile the project using the following command:

    make -f makefile.gcc
    

Step 4: Executing Fuzz Tests

• Create test cases: Design input files that cover various scenarios, including valid and invalid inputs.
• Run the fuzzing tools:
  • Use AFL to run your fuzz tests:

    afl-fuzz -i input_dir -o output_dir -- ./7z [options]
    

  • Monitor the output for crashes or unexpected behavior.

Step 5: Analyzing Results and Fixing Crashes

• Review crash reports: Analyze the logs generated by your fuzzing tool to identify any crashes.
• Debugging:
  • Use debugging tools such as gdb to trace the source of the crashes.
  • Investigate the code where the crash occurred and make necessary fixes.
• Verify fixes: Rerun the fuzz tests to ensure that the identified issues have been resolved.

Conclusion

In this tutorial, we've covered the basics of the 7z codebase, the principles of software fuzzing, and how to set up a fuzzing environment. By applying these techniques, you can enhance your understanding of software security and improve the robustness of applications. As a next step, consider diving deeper into advanced fuzzing techniques and exploring additional vulnerabilities in other open-source projects. Happy coding!