Stack-Based Buffer Overflows on Windows x86

Stack-Based Buffer Overflows on Windows x86  Medium

This module is your first step into Windows Binary Exploitation, and it will teach you how to exploit local and remote buffer overflow vulnerabilities on Windows machines.

Created by 21y4d

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Summary

Windows binary exploitation has advanced throughout the years, from basic stack overflow techniques to advanced security bypass techniques and heap exploitation. To reach a level of understanding that enables us to successfully exploit even the most advanced applications, we must have a firm grasp of the fundamentals of Windows binary exploitation, which is the main aim of this module.

The Stack-Based Buffer Overflows on Windows x86 module is your first step in Windows Binary Exploitation, and it will take you through the following:

  1. What is binary exploitation and buffer overflows
  2. How to debug Windows programs
  3. Basics of local and remote fuzzing of Windows programs
  4. Finding and using return instructions to subvert the program execution flow
  5. Crafting malicious payloads and scripts to gain local and remote control through buffer overflow vulnerabilities
  6. Developing a functional multi-tier Python exploit for stack-based buffer overflows, which can be used as a basis for other buffer overflow exercises

Throughout the module, we will be attacking two different programs. First, we will generate a malicious .wav file that exploits a buffer overflow vulnerability in an audio converter to perform local privilege escalation. Then, we will move towards remote exploitation by attacking a remote server to gain remote code execution over it after debugging the vulnerable binary locally and developing an exploit.

In addition to teaching the above topics, this module will also cover:

  • A short history of stack-based buffer overflows, and real-world examples of these vulnerabilities
  • The process behind developing a stack-based buffer overflow
  • Fuzzing a program's fields and parameters
  • Identifying the exact offset of our input's location within the buffer
  • Controlling the address of the return instruction
  • Identifying and eliminating potentially bad characters from our exploit
  • Learning multiple methods of finding and utilizing return instructions to subvert execution flow
  • Generating shellcodes and executing them through our return instructions
  • Fuzzing a listening port gradually to identify the length of its buffer precisely
  • Adapting our local exploit to attack remote ports

This module is broken down into sections with accompanying hands-on exercises to practice each of the tactics and techniques we cover.
The module ends with a practical hands-on skills assessment to gauge your understanding of the various topic areas.

As you work through the module, you will see example commands and command output for the various topics introduced. It is worth reproducing as many examples as possible to reinforce further the concepts presented in each section. You can do this in the PwnBox provided in the interactive sections or your virtual machine.

You can start and stop the module at any time and pick up where you left off. There is no time limit or "grading," but you must complete all of the exercises and the skills assessment to receive the maximum number of cubes and have this module marked as complete in any paths you have chosen.

The module is classified as "Medium" and assumes a working knowledge of the Windows command line and an understanding of information security fundamentals.

This module assumes a basic understanding of computer, processor, and memory architecture and will build on this understanding to teach how stack-based buffer overflows work. Therefore, we strongly recommended finishing the Intro to Assembly Language module before starting this one to easily grasp all of the concepts taught in this module and learn the basics necessary for binary exploitation. Also, as this module also teaches the basics of building a Python exploit, the Introduction to Python 3 should help.

In addition to the above, a firm grasp of the following modules can be considered prerequisites for successful completion of this module:

  • Learning Process
  • Windows Fundamentals
  • Introduction to Python 3
  • Intro to Assembly Language

Sections

  • Buffer Overflow
  • Debugging Windows Programs
  • Fuzzing Parameters
  • Controlling EIP
  • Identifying Bad Characters
  • Finding a Return Instruction
  • Jumping to Shellcode
  • Remote Fuzzing
  • Building a Remote Exploit
  • Remote Exploitation
  • Skills Assessment

Relevant Paths

This module progresses you towards the following Paths

Card image
Intro to Binary Exploitation

Hard 62 Sections

Cubes Required: 570

Binary exploitation is a core tenet of penetration testing, but learning it can be daunting. This is mainly due to the complexity of binary files and their underlying machine code and how binary files interact with computer memory and the processor. To learn the basics of binary exploitation, we must first have a firm grasp of Computer Architecture and the Assembly Language. To move into more advanced binary exploitation, we must have a firm grasp on basic buffer overflow attacks, principles such as CPU architecture, and CPU registers for 32-bit Windows and Linux systems. Furthermore, a strong foundation in Python scripting is essential for writing and understanding exploit scripts.

 Introduction to Python 3

Easy 14 Sections

Automating tedious or otherwise impossible tasks is highly valued during both penetration testing engagements and everyday life. Introduction to Python 3 aims to introduce the student to the world of scripting with Python 3 and covers the essential building blocks needed for a beginner to understand programming. Some advanced topics are also covered for the more experienced student. In a guided fashion and starting soft, the final goal of this module is to equip the reader with enough know-how to be able to implement simple yet useful pieces of software.

 Intro to Assembly Language

Medium 24 Sections

This module builds the core foundation for Binary Exploitation by teaching Computer Architecture and Assembly language basics.

 Stack-Based Buffer Overflows on Linux x86

Medium 13 Sections

Buffer overflows are common vulnerabilities in software applications that can be exploited to achieve remote code execution (RCE) or perform a Denial-of-Service (DoS) attack. These vulnerabilities are caused by insecure coding, resulting in an attacker being able to overrun a program's buffer and overwrite adjacent memory locations, changing the program's execution path and resulting in unintended actions.

 Stack-Based Buffer Overflows on Windows x86

Medium 11 Sections

This module is your first step into Windows Binary Exploitation, and it will teach you how to exploit local and remote buffer overflow vulnerabilities on Windows machines.

To start this course Sign Up!