DeFiFoundrySolidity
16,653 OP
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Submission Details
Severity: medium
Valid

Unclaimed `Claimable` Funds in `StrategyMainnet`, `StrategyArb`, and `StrategyOp` Contracts

Summary

The StrategyMainnet, StrategyArb, and StrategyOp contracts all fail to claim available claimable funds from the transmuter during the _harvestAndReport() process. This oversight prevents the strategies from realizing these assets, leading to inaccurate reporting of total assets and missed opportunities to optimize yield for users. This issue exists in the deployed code, and testing confirms that the vulnerability persists.

Vulnerability Details

The vulnerability resides in the _harvestAndReport() function in all three contracts. The code successfully detects the presence of claimable funds using transmuter.getClaimableBalance(address(this)) > 0, but does not execute the transmuter.claim() function to collect these funds. As a result, the claimable tokens remain unclaimed, causing the strategy to report incorrect total assets. The unclaimed funds are excluded from the reported balance, and the strategy fails to utilize them for reinvestment.

Description

During each invocation of _harvestAndReport(), the function calculates total assets but neglects to include claimable funds. This results in the following issues:

  • Inaccurate Reporting: Total assets are understated as claimable funds are not accounted for.

  • Missed Opportunities: Unclaimed funds remain idle, reducing the yield generated for users.

  • Suboptimal Strategy Performance: Users and stakeholders are deprived of returns that could have been achieved by reinvesting the claimable assets.

Impact

The unclaimed claimable funds directly affect the strategy's performance and reporting accuracy. Users face reduced yield over time, as the strategy fails to maximize the assets under management. Furthermore, the inaccurate reporting of total assets undermines the transparency and reliability of the strategy's operations.

Proof of Concept

Referenced Code

The _harvestAndReport() original function:

function _harvestAndReport() internal override returns (uint256 _totalAssets) {
uint256 claimable = transmuter.getClaimableBalance(address(this));
if (claimable > 0) {
// transmuter.claim(claimable, address(this)); // Not executed in the original code
}
uint256 unexchanged = transmuter.getUnexchangedBalance(address(this));
uint256 underlyingBalance = underlying.balanceOf(address(this));
uint256 assetBalance = asset.balanceOf(address(this));
_totalAssets = unexchanged + assetBalance + underlyingBalance;
}

Test Code

The following test demonstrates the vulnerability:

function test_claimableNotClaimed() public {
console.log("Depositing 1e18 synthetic into strategy...");
vm.prank(user);
strategy.deposit(1e18, user);
console.log("Setting claimable to 0.5e18...");
mockTransmuter.setClaimable(address(strategy), 0.5e18);
uint256 claimableBefore = mockTransmuter.getClaimableBalance(
address(strategy)
);
console.log("Claimable before report:", claimableBefore);
assertEq(claimableBefore, 0.5e18, "Claimable not set correctly");
console.log("Calling report() as keeper...");
vm.prank(address(this));
strategy.report();
uint256 claimableAfter = mockTransmuter.getClaimableBalance(
address(strategy)
);
console.log("Claimable after report:", claimableAfter);
assertEq(
claimableAfter,
claimableBefore,
"Claimable should remain unchanged because it's not claimed"
);
uint256 totalAssetsAfter = strategy.totalAssets();
console.log("Total assets after report:", totalAssetsAfter);
assertEq(totalAssetsAfter, 1e18, "Total assets changed unexpectedly");
console.log("Test completed successfully. The bug is confirmed.");
}

Test Logs

Setting up test environment...
Deploying mockTransmuter and test strategy...
Transferring 1e18 synthetic tokens to 'user' and approving strategy...
Setup complete.
Depositing 1e18 synthetic into strategy...
Setting claimable to 0.5e18...
Claimable before report: 500000000000000000
Calling report() as keeper...
Claimable after report: 500000000000000000
Total assets after report: 1000000000000000000
Test completed successfully. The bug is confirmed

Explanation

Before the mitigation:

  • The claimable balance remains unchanged at 0.5e18 after calling report().

  • The totalAssets value does not account for the claimable funds, confirming the issue.

Tools Used

  • Foundry: Used for testing and running proofs of concept.

  • Manual Code Review: Identified the missing claim() call.

Recommendations

Mitigation Code

To resolve the issue, the _harvestAndReport() function should actively claim the available funds. The following code implements this fix:

function _harvestAndReport() internal override returns (uint256 _totalAssets) {
uint256 claimable = transmuter.getClaimableBalance(address(this));
if (claimable > 0) {
transmuter.claim(claimable, address(this)); // <@ Claim now executed
}
uint256 unexchanged = transmuter.getUnexchangedBalance(address(this));
uint256 underlyingBalance = underlying.balanceOf(address(this));
uint256 assetBalance = asset.balanceOf(address(this));
// @> After claiming, _totalAssets should now include the previously claimable funds
_totalAssets = unexchanged + assetBalance + underlyingBalance;
}

Test Code (Post-Mitigation)

function test_claimableClaimedAfterFix() public {
console.log("Depositing 1e18 synthetic into strategy...");
vm.prank(user);
strategy.deposit(1e18, user);
console.log("Setting claimable to 0.5e18...");
mockTransmuter.setClaimable(address(strategy), 0.5e18);
uint256 claimableBefore = mockTransmuter.getClaimableBalance(
address(strategy)
);
console.log("Claimable before report (fixed):", claimableBefore);
assertEq(claimableBefore, 0.5e18, "Claimable not set correctly");
console.log("Calling report() as keeper (with fix)...");
vm.prank(address(this));
strategy.report();
uint256 claimableAfter = mockTransmuter.getClaimableBalance(
address(strategy)
);
console.log("Claimable after report (fixed):", claimableAfter);
assertEq(claimableAfter, 0, "Claimable should now be zero after claim");
uint256 totalAssetsAfter = strategy.totalAssets();
console.log("Total assets after report (fixed):", totalAssetsAfter);
console.log(
"Test completed. The claimable was successfully claimed after the fix."
);
}

Test Logs (Post-Mitigation)

Setting up test environment (with fix)...
Transferring 1e18 synthetic tokens to 'user' and approving strategy...
Setup complete.
Depositing 1e18 synthetic into strategy...
Setting claimable to 0.5e18...
Claimable before report (fixed): 500000000000000000
Calling report() as keeper (with fix)...
Claim executed, claimable was: 500000000000000000
After harvest (fixed): unexchanged: 1000000000000000000
After harvest (fixed): asset bal: 0
After harvest (fixed): underlying bal: 0
After harvest (fixed): total assets: 1000000000000000000
Claimable after report (fixed): 0
Total assets after report (fixed): 1000000000000000000
Test completed. The claimable was successfully claimed after the fix.

Outcome

The claimable funds are successfully claimed during the _harvestAndReport() process. The totalAssets value now reflects the true value of the strategy, and the issue is resolved.

  • Pre-mitigation: The claimable value remains unchanged at 0.5e18 following the report() execution. This behavior indicates that the claim process is not performed, leaving the funds idle and unutilized.

  • Post-mitigation: The claimable value is reduced to 0 after report() is called. This confirms that the mitigation successfully executes the claim operation, ensuring that the previously unclaimed funds are now incorporated into the strategy’s total assets.

Updates

Appeal created

inallhonesty Lead Judge 7 months ago
Submission Judgement Published
Invalidated
Reason: Design choice
rolando Submitter
7 months ago
inallhonesty Lead Judge
7 months ago
inallhonesty Lead Judge 7 months ago
Submission Judgement Published
Validated
Assigned finding tags:

Incorrect accounting in `_harvestAndReport` claimable should be included

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