EthCon 2024 CTF

Problem

EthCon Korea 2024 needed a hands-on security track that went beyond talks — developers retain attack and defense reasoning far better when they exploit vulnerable contracts themselves than when they watch slides about them. The event needed blockchain-focused challenges spanning multiple categories, calibrated across difficulty tiers, and running on competition infrastructure that could be trusted with live scoring for a conference audience.

Approach

• Progressive difficulty laddering from beginner to advanced so newcomers gain footing on early challenges before confronting subtle exploits that would otherwise discourage them.
• Coverage across attack classes (reentrancy, access control, logic flaws, cryptography, bytecode reverse engineering) rather than depth in a single class, to match the heterogeneous skill set of a conference audience.
• Full solvability testing for every challenge before release, because an unsolvable or ambiguous CTF challenge destroys participant trust for the remainder of the event.
• CTFd over a custom scoreboard for battle-tested dynamic scoring, team management, and registration under live-event pressure.
• Dockerized deployments so challenge environments could be reset, scaled, and torn down without interfering with scoring.

Implementation

Challenge Design

• Created smart contract vulnerability challenges covering common attack vectors
• Designed progressive difficulty levels from beginner to advanced
• Built challenges around reentrancy, access control, and logic flaws
• Tested all challenges for solvability and expected difficulty calibration

Challenge Categories

• Smart Contract Exploitation: Identifying and exploiting Solidity vulnerabilities
• Cryptography: Blockchain-specific cryptographic puzzles
• Reverse Engineering: Analyzing deployed contract bytecode

Platform Operation

• Deployed and configured CTFd platform for the competition
• Managed dynamic scoring and real-time leaderboard
• Handled participant registration and team management
• Provided live support during the competition

Outcome

• Successfully hosted the CTF event at EthCon Korea 2024, one of Korea’s premier Ethereum conferences.
• Challenge set covering smart contract exploitation, cryptography, and reverse engineering across a beginner-to-advanced difficulty curve.
• CTFd platform operated with dynamic scoring and real-time leaderboard throughout the competition.
• Engaged developers in hands-on blockchain security education on live infrastructure.

Technologies

• Platform: CTFd (Python)
• Challenges: Solidity, Foundry
• Infrastructure: Docker, deployment automation