QuantAMM

Summary

The UpdateWeightRunner::setQuantAMMSwapFeeTake function includes a check to ensure that the _quantAMMSwapFeeTake parameter is less than 100%. However, the use of <= operator in require(_quantAMMSwapFeeTake <= 1e18, "Swap fee must be less than 100%"); allows the swap fee to be set to exactly 100%. This could lead to scenarios where the protocol charges an astronomically high swap fee, potentially causing user dissatisfaction, lack of trust in the protocol, and decreased adoption.

Vulnerability Details

• The setQuantAMMSwapFeeTake function allows an administrator (quantammAdmin) to update the quantAMMSwapFeeTake value, which represents the swap fee in a scaled format (e.g., 1e18 represents 100%).

• The check require(_quantAMMSwapFeeTake <= 1e18, "Swap fee must be less than 100%") permits the fee to be set to exactly 100%, which is likely unintended given the expectation of a fee being "less than 100%."

• A 100% swap fee effectively prevents meaningful use of the protocol, as users would lose all their assets in any transaction.

Impact

• Protocol Trust: Users may lose trust in the protocol if a 100% fee is charged, especially if done maliciously or by mistake.

• Financial Damage: If set to 100%, any swap transaction would effectively confiscate users’ assets, leading to severe financial losses.

• Adoption Risk: A protocol perceived as unsafe or poorly managed would face reduced adoption and diminished reputation in the market.

Tools Used

Manual Review

Recommendations

• Modify the Condition: Change the require statement to use the < operator instead of <=, ensuring that _quantAMMSwapFeeTake cannot equal 100%.

  - require(_quantAMMSwapFeeTake <= 1e18, "Swap fee must be less than 100%");

  + require(_quantAMMSwapFeeTake < 1e18, "Swap fee must be less than 100%");

• Set Reasonable Limits: Consider imposing a maximum fee threshold (e.g., 5% or 0.05e18) to ensure fees remain reasonable and user-friendly.

  - require(_quantAMMSwapFeeTake <= 1e18, "Swap fee must be less than 100%");

  + require(_quantAMMSwapFeeTake < 0.05e18, "Swap fee must be less than 5%");

By implementing these changes, the protocol will prevent unintended or malicious configuration of the swap fee, preserving user trust and ensuring operational integrity.