Echo Escape 1 - Basic Buffer Overflow Tutorial (Ret2Win) | picoCTF 2026

In this picoCTF 2026 writeup for Echo Escape 1, we walk through a fundamental 64-bit buffer overflow (Ret2Win) exploit. First, we perform binary analysis using checksec and GDB (pwndbg) to identify the lack of stack canaries and PIE. Then, we use a cyclic pattern to calculate the 40-byte offset required to overwrite the return address. Finally, we develop a pwntools Python script to hijack the execution flow and call the hidden 'win' function to capture the flag. Links & Resources Challenge: https://play.picoctf.org/practice/challenge/755 Tools Used: GDB (pwndbg), Pwntools, Python, Checksec Video Chapters 00:00 Introduction to Echo Escape 1 00:43 Binary Analysis & Security Mitigations (checksec) 01:53 Source Code Walkthrough (Buffer Mismatch) 02:29 Stack Memory & Overflow Theory 04:04 Finding the 'win' Function Address in GDB 04:54 Calculating the Offset with Cyclic Patterns 06:53 Triggering the Segmentation Fault (RIP Overwrite) 08:27 Writing the Pwntools Exploit Script 11:12 Running the Exploit & Flag Capture 11:51 Mitigation Strategies & Outro #picoctf2026 #bufferoverflow #binaryexploitation #pwn #cybersecurity #ethicalhacking #reverseengineering