Video on how to solve Problem #40: NotOptimisticPortal

[typicalHuman]

https://www.youtube.com/watch?v=xEHdz8rlGvA

[jimmychu0807]

I wish it was as easy as you mentioned. Your direction is correct, but you need a way to construct the merkle trie proof to satisfy the _verifyMessageInclusion() function. My problem is on how to construct such merkle trie proof.

[typicalHuman]

You're right that a proof also has to be created to complete the exploit, but I wasn’t particularly interested in constructing it. My goal was to demonstrate the vulnerability path and how to take control of the contract. Creating the proof is mostly boring work, so I skipped it for the sake of keeping it interesting tbh.