Alchemix Transmuter
Alchemix
DeFiFoundrySolidity
16,653 OP
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Submission Details
Severity: medium
Invalid

Risks of Using block.timestamp in _swapUnderlyingToAsset Leading to Potential Transaction Failures and Exploitation

eta

Summary

The _swapUnderlyingToAsset function uses block.timestamp as the deadline for swaps, which introduces risks related to transaction delays, price inaccuracies, and potential exploitation in the contracts of StrategyArb.sol and src/StrategyOp.sol.

Vulnerability Details

src/StrategyArb.sol:_swapUnderlyingToAsset#L87
src/StrategyOp.sol:_swapUnderlyingToAsset#L102

function _swapUnderlyingToAsset(uint256 _amount, uint256 minOut, IVeloRouter.route[] calldata _path) internal {
// TODO : we swap WETH to ALETH -> need to check that price is better than 1:1
// uint256 oraclePrice = 1e18 * 101 / 100;
require(minOut > _amount, "minOut too low");
​
uint256 underlyingBalance = underlying.balanceOf(address(this));
require(underlyingBalance >= _amount, "not enough underlying balance");
IVeloRouter(router).swapExactTokensForTokens(_amount, minOut, _path, address(this), block.timestamp);
// @audit `block.timestamp` as a swap deadline without additional buffer or user-defined parameters
}
​

Using block.timestamp as a swap deadline without additional buffer or user-defined parameters can lead to the following issues:
- Transaction Delay Failures: If the transaction is delayed (e.g., due to network congestion), the deadline may be missed, causing the swap to revert unnecessarily.
- Price Outdated Risks: Transactions processed later may execute at outdated and unfavorable prices.

Impact

  • Reverts due to strict timing can frustrate users and degrade the contract's reliability.

  • Users might incur losses from failed swaps or unintended price fluctuations.

  • Lack of flexibility in setting deadlines cause fund losses for the Alchemix.

Recommendations

Allow users to specify a custom buffer to account for network delays:

+ uint256 deadline = block.timestamp + userDefinedBuffer;
+ require(userDefinedBuffer <= MAX_BUFFER, "Buffer exceeds limit");
Updates

Appeal created

inallhonesty Lead Judge 8 months ago
Submission Judgement Published
Invalidated
Reason: Known issue
inallhonesty Lead Judge 8 months ago
Submission Judgement Published
Invalidated
Reason: Known issue

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