DatingDapp

Summary

The LikeRegistry contract's reward distribution mechanism can be manipulated through a timing attack that allows malicious users to minimize their capital requirements while maximizing potential returns.

Vulnerability Details

The likeUser function creates an asymmetric economic incentive where the second person to "like" determines when the match occurs and the rewards are distributed. This can be exploited by monitoring pending transactions and timing likes to maximize return

##POC

Attacker monitors mempool for likeUser transactions
When they see a high-value like (e.g., 10 ETH), they:

Front-run with a minimum 1 ETH like to the sender
Wait for the original high-value transaction
Back-run with their own likeUser call

This guarantees them a match with minimal capital risk

Impact

System can be gamed by sophisticated users

Legitimate users may lose potential matches to attackers
Creates negative user experience

Tools Used

Manual Analysis, foundry

Recommendations

Implement a minimum holding period before likes can be matched

Add randomization to match timing

Implement minimum stake requirements that scale with platform usage

Consider a batch processing system for matches

Add anti-MEV protections

Consider implementing a commit-reveal scheme for likes