htb-meetup-pwn

Binary exploitation (pwn) workshop materials for HTB Meetup.

Overview

This repository contains hands-on challenges and a mini-CTF for learning buffer overflow exploitation on both x86 (32-bit) and x64 (64-bit) architectures.

Structure

├── docs/            # Workshop materials
│   ├── preparation.md/pdf  # Setup guide for attendees
│   └── slides.md/pdf       # Presentation slides
│
├── handson/         # Guided practice challenges
│   ├── x64/         # 64-bit ret2win challenge
│   └── x86/         # 32-bit ret2win challenge
│
├── mini-ctf/        # CTF-style challenges (Docker-based)
│   ├── x64/         # 64-bit challenge with hidden flag
│   └── x86/         # 32-bit challenge with hidden flag
│
└── scripts/         # Helper scripts
    └── install-tools.sh    # Install required tools on Kali

Challenges

Hands-on Challenges

Simple ret2win challenges to practice the basics:

• Overflow a buffer to overwrite the return address
• Redirect execution to a win() function that prints the flag

Mini-CTF

More realistic challenges running in Docker containers:

• Find and exploit the buffer overflow vulnerability
• Call a hidden get_flag() function to read flag.txt

Requirements

• GCC with multilib support
• Python 3 with pwntools
• Docker & Docker Compose (for mini-CTF)
• GDB with pwndbg
• Ghidra for reverse engineering

Kali Linux users: Run scripts/install-tools.sh to install all required tools.

Quick Start

# Build challenges
cd handons && ./build.sh
cd mini-ctf && docker-compose up -d

# Try the x64 hands-on
cd handons/x64
./challenge
python solve.py

Learning Objectives

• Understanding stack-based buffer overflows
• Finding offsets to overwrite return addresses
• Using pwntools for exploit development
• x86 vs x64 calling conventions and stack alignment

Writeup

A detailed writeup for these challenges is available at: HTB Meetup IIUM 2025 - Intro to PWN