Ethernaut
Small Solidity security levels from OpenZeppelin. Good for learning one exploit idea at a time.
Start: Fallout, Delegation, Reentrancy
A curated index of Solidity and Web3 security challenges. Filter by level, format, and topic. Start solving faster.
Recommended order
7 CTFs shown
Small Solidity security levels from OpenZeppelin. Good for learning one exploit idea at a time.
Start: Fallout, Delegation, Reentrancy
Older, still-useful Ethereum puzzles covering authorization, math, hashes, calls, and Solidity basics.
Start: Token sale, Guess the number, Token whale
A broad set of smart contract challenges organized around common bug classes and exploit patterns.
Start: Start with the beginner Solidity set
Short Solidity and EVM security quizzes. Useful between hands-on CTF sessions.
Start: RACE 1, then the Solidity security rounds
Modern Damn Vulnerable DeFi challenges using Foundry and protocol-level DeFi scenarios.
Start: Unstoppable, Naive Receiver, Truster
Hard smart contract CTF archives with EVM, DeFi, math, and protocol-level puzzles.
Start: Open the 2023 archive and solve a low-point task first
Reproduce real DeFi incidents and compare your exploit against a working proof of concept.
Start: Pick one small incident PoC and replay the test
Try a broader search like Solidity, DeFi, beginner, exploit, or EVM.
Start here if you do not know which challenge to open first.
A smart contract CTF is a security challenge where you exploit intentionally vulnerable blockchain contracts. These challenges help developers and auditors practice bugs such as reentrancy, access control failures, oracle manipulation, and broken accounting logic.
Ethernaut and Capture the Ether are good beginner-friendly options because they use smaller challenges that introduce common Ethereum and Solidity security concepts before moving into DeFi complexity.
Damn Vulnerable DeFi is a strong DeFi-focused practice resource. It covers scenarios involving flash loans, lending, governance, oracles, AMMs, and token mechanics.
No. CTFs are useful for exploit practice, but real audits also require code review discipline, threat modeling, protocol understanding, invariant thinking, reporting skills, and familiarity with production codebases.
Use writeups after a serious attempt. Reading too early can make the challenge feel clear without building the debugging and reasoning skills needed for real audits.