Snow Crash

Overview

This repository contains my solutions and detailed writeups for the Snow Crash project, an introductory cybersecurity challenge from the 42 curriculum.

The project consists of a series of 14 levels, each designed to teach a different security concept. The goal is to start as a low-privilege user (levelXX) and find a vulnerability to gain access to the corresponding high-privilege account (flagXX). Once access is gained, the getflag command reveals the token needed to access the next level.

Repository Structure

The solutions for each level are organized into their own directories, as required by the project subject:

• levelXX/flag: A file containing the token retrieved for that level.
• levelXX/resources/README.md: The detailed, step-by-step writeup explaining the vulnerability, the exploitation process, and the conclusion for that level.

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Challenge Summary & Writeups

Here is an overview of the concepts covered in each level. You can click the level number to go directly to the full writeup.

Level	Core Concept / Vulnerability	Tools & Techniques Used
Level00	Basic Cryptanalysis & Filesystem Exploration	find, ROT Cipher, C++ (Decryption)
Level01	Legacy Password Cracking	DES crypt hash, /etc/passwd, Dictionary Attack, C++ (crypt())
Level02	Network Traffic Analysis	PCAP File, tshark, Hex/ASCII Decoding (Backspace), SCP, Vagrant
Level03	Privilege Escalation (SUID)	SUID Binary, PATH Environment Variable Manipulation
Level04	Web Command Injection	Perl CGI Script, Backtick (`) Injection, curl
Level05	Cron Job Exploitation	Cron Task Analysis, Insecure Shell Script, /tmp Directory
Level06	PHP Code Injection	preg_replace /e Modifier, String Interpolation (${...}), SUID Binary
Level07	Environment Variable Injection	SUID Binary, getenv(), system() call, LOGNAME variable
Level08	Path Traversal / Symlink Attack	SUID Binary, strstr Check Bypass, Symbolic Links (ln -s)
Level09	Custom Cipher Reverse Engineering	Positional Cipher, Known-Plaintext Attack, C (Decryption)
Level10	TOCTOU Race Condition	SUID Binary, access() vs open() Discrepancy, Symlink Swapping
Level11	Network Service Command Injection	Lua Service, io.popen(), Command Injection, Reverse Shell, netcat
Level12	Command Injection (Sanitization Bypass)	Perl CGI, Nested Backticks, Wildcard (*) Execution
Level13	UID Check Bypass	SUID Binary, getuid() Check, Binary Analysis, Vagrant (User creation)
Level14	Advanced Reverse Engineering	Anti-Debugging (ptrace), LD_PRELOAD Check, UID-based Auth

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Project Structure

snow-crash/
├── README.md
├── snow-crash.gif
└── level00-14/
    ├── flag                    # Retrieved token
    └── resources/
        ├── README.md           # Detailed writeup
        └── [exploit files]     # Scripts, code, tools

Disclaimer

This repository is for educational purposes only, documenting my work on the 42 curriculum. These solutions are intended as a reference for students who have already completed or are actively working on the project.