Web3 CTF Notes

Personal Web3 CTF notes covering exploit patterns, vulnerability classes, and lessons from practice challenges.

This repository is a learning record for Web3 security practice. The notes focus on understanding why a challenge is vulnerable, how to reproduce the exploit path, and what security lesson should be carried into real audits.

Notes

• These notes are for Web3 security learning and exploit-pattern practice.
• They are not real-world vulnerability disclosures.
• Some early notes are intentionally lightweight and may be revised as my audit methodology improves.
• The solutions/the-ethernaut directory contains Remix-written Solidity contracts used while solving Ethernaut levels. These are kept as historical solution artifacts, not as a polished Foundry test suite.

The Ethernaut

Challenge	Topic	Notes
00. Hello Ethernaut	Contract interaction basics	Notes
01. Fallback	Ownership transfer through fallback logic	Notes
02. Fallout	Constructor naming mistake	Notes
03. Coin Flip	Predictable randomness	Notes
04. Telephone	tx.origin misuse	Notes
05. Token	Integer underflow in old Solidity versions	Notes
06. Delegation	delegatecall and storage context	Notes

Repository Layout

src/
  the-ethernaut/     Ethernaut challenge notes
solutions/
  the-ethernaut/     Remix-written Ethernaut solution contracts
markdown-template.md Template for future notes

Topics Covered

• Solidity basics and contract interaction
• Fallback functions and low-level calls
• Constructor and initialization mistakes
• Weak randomness
• tx.origin authorization bugs
• Integer overflow and underflow
• delegatecall storage-context risks