Linux Usermode Exploitation 101

Updated July 25, 2025

Introduction

The aim of this course is to train students in the fundamentals of Linux usermode exploitation. You will learn how stack memory works, how buffer overflows happen, and how attackers can take control of a vulnerable program.

By the end of the series, you’ll be able to analyze simple C programs, identify memory corruption bugs, and write basic exploits to gain shell access — all in a safe, local lab environment.

This training is ideal for anyone interested in cybersecurity, penetration testing, or low-level Linux internals.

The main goal of this series is to teach students through hands-on practice. Each task builds on the skills learned in previous challenges, helping students to strengthen and apply their knowledge step by step.

Level-Based Learning Approach

This course is structured as a progressive, level-based series where each level introduces a specific exploitation concept, reinforces previously learned techniques, and adds new, practical skills to your toolkit. You learn by doing — and by progressing. Passing each level means you’ve mastered a key concept in Linux usermode exploitation.

Stack Overflows for Beginners Series

LevelSkills Gained
Level 1Basic Stack-Based Buffer Overflows
Static Code Analysis
Disassembly with GDB
Understanding Control Flow
Level 2Controlling EIP
Identification of the Return Address
Return-to-Function (ret2func)
Level 3Identifying Bad Characters
Generating Shellcode
Finding a Place for Large Shellcodes
Locating Usable Gadgets
PoC Writing
Level 4Reverse Shell Execution
Manual Gadget Hunting
Level 5Privilege Escalation
Understanding SUID Behavior
Published July 24, 2025
Category: Blog, Exploit Dev, Walkthrough