Pieces Protocol

Summary

in TokenDivider::buyOrder when a buyer wants to buy a sell order, he has to send the amount of Ether equal to the sell order price + protocol fees. The seller's fees are then subtracted from the order price. In the current implementation the fee protocol fees and sellerFee are calculated as follows:

Due to integer division truncation, orders priced below 200 wei result in zero seller fees and reduced protocol fees. This creates a loophole where sellers can split large orders into smaller ones (each <200 wei) to avoid paying fees entirely.

Additionally, the protocol fees can be bypassed too if the price of each order is below 100 wei.

Vulnerability Details

Example Scenarios

Key Observation:
Splitting a 1500 wei order into ten 150 wei orders reduces total fees from 22 wei to 10 wei, costing the protocol 55% of its revenue.

Impact

Malicious users can bypass fees by splitting orders into amounts below 200 wei.

Tools Used

Manual Review

Recommendations

in TokenDivider::sellERC20 we can add a validation check for price parameter to be more than 199 wei.