RebateFi Hook
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Beginner FriendlyDeFi
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Submission Details
Severity: low
Valid

Fee Calculation Precision Error Leading to Inaccurate Event Logging

minos

Fee Calculation Precision Error Leading to Inaccurate Event Logging

Description

  • In a standard ReFi token sell transaction, the hook contract should accurately compute and record the actual fee amount charged for effective monitoring and data analysis.

  • The _beforeSwap function utilizes an incorrect fee calculation precision (100000 instead of 1000000), resulting in a discrepancy between the fee amount recorded in the event and the actual amount charged.

function _beforeSwap(
address sender,
PoolKey calldata key,
SwapParams calldata params,
bytes calldata
) internal override returns (bytes4, BeforeSwapDelta, uint24) {
// ... other logic ...
} else {
fee = sellFee;
@> uint256 feeAmount = (swapAmount * sellFee) / 100000; // ❌ Error: Using 100000 instead of 1_000_000
emit ReFiSold(sender, swapAmount, feeAmount);
}
}

Risk

Likelihood:

  • This error in calculation is triggered with every user's ReFi token sale.

  • All sell transaction event logs will document incorrect fee amounts.

  • Monitoring systems and data analysis tools will consistently receive inaccurate information.

Impact:

  • Event recording distortion: The feeAmount parameter in the ReFiSold event is 10 times the actual charged amount, leading to completely erroneous monitoring data.

  • Misleading data analysis: Analysis tools based on event logs will significantly overestimate actual fee revenue, impacting decision-making.

  • User experience confusion: If front-end applications display fee data from events, users will see amounts that do not match the actual deductions.

Proof of Concept

  • N/A

Recommended Mitigation

function _beforeSwap(
address sender,
PoolKey calldata key,
SwapParams calldata params,
bytes calldata
) internal override returns (bytes4, BeforeSwapDelta, uint24) {
// ... other logic ...
} else {
fee = sellFee;
- uint256 feeAmount = (swapAmount * sellFee) / 100000;
+ uint256 feeAmount = (swapAmount * sellFee) / 1000000;
emit ReFiSold(sender, swapAmount, feeAmount);
}
}
Updates

Lead Judging Commences

chaossr Lead Judge 12 days ago
Submission Judgement Published
Validated
Assigned finding tags:

Incorrect denominator (100000 instead of likely 1000000 or 10000) in fee calculation for ReFiSold event.

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