ArkProject: NFT Bridge

https://github.com/Cyfrin/2024-07-ark-project/blob/273b7b94986d3914d5ee737c99a59ec8728b1517/apps/blockchain/ethereum/src/Messaging.sol#L46

The _consumeMessageAutoWithdraw function checks if a message hash is already consumed (WITHDRAW_AUTO_CONSUMED) and reverts if it is. However, there's no mechanism to prevent an attacker from repeatedly calling this function with the same hash, even if it's not a valid message.

• Impact: This could lead to a denial-of-service (DoS) attack where legitimate users are unable to withdraw their tokens because the contract is constantly reverting due to an attacker's actions. While this doesn't directly lead to a loss of funds, it disrupts the bridge's functionality and user experience.

• Recommendation: Implement a mechanism to prevent or mitigate DoS attacks. This could involve rate limiting, requiring a deposit or fee for message consumption attempts, or using a more sophisticated approach like a challenge-response mechanism.