Windows Exploitation: Beginner’s Guide to Buffer Overflow (Old OSCP-Level)

Buffer overflow vulnerabilities remain one of the most fundamental yet powerful techniques in exploitation. By carefully crafting a malicious input, an attacker can overwrite key memory addresses, hijack program execution, and gain unauthorized access to a system.

In this guide, we will walk through a real-world buffer overflow exploit on SLMail 5.5, a vulnerable POP3 mail server for Windows. We will cover every critical step — from initial fuzzing to shellcode execution — ensuring you understand not just how to exploit the vulnerability, but why each step is necessary.

This hands-on tutorial will help you develop essential exploitation skills, including:

✔️ Identifying buffer overflow vulnerabilities
✔️ Locating EIP overwrite offsets
✔️ Finding bad characters and safe return addresses
✔️ Generating shellcode for remote access

By the end of this guide, you will have successfully gained a remote shell on the target system, demonstrating how attackers can weaponize memory corruption vulnerabilities.

Ensure you have a Windows machine (Windows 7 recommended) with the following installed: