Core Contracts

Summary

The Treasury.sol contract allows deposits from any ERC-20 token, which can lead to denial of service (DoS) conditions if a token unexpectedly transfers the maximum possible balance (type(uint256).max). Some legitimate tokens, such as Compound V3 tokens (e.g., cUSDCv3), exhibit this behavior where calling transferFrom() with a high value results in transferring the sender's entire balance. If an administrator deposits such a token, _balances[token] and _totalValue may become inconsistent, causing reverts and/or preventing further deposits or withdrawals.

Vulnerability Details

Incorrect _balances[token] Leading to DoS

Root Cause:

1. The deposit() function updates _balances[token] and _totalValue upon a successful transfer:

   _balances[token] += amount;

   _totalValue += amount;

2. Some ERC-20 tokens, including legitimate ones like cUSDCv3 from Compound V3, behave in a way where calling transferFrom() with type(uint256).max results in transferring the entire token balance of the sender.

3. If an administrator deposits such a token, _balances[token] could reach type(uint256).max, making any further deposit attempt revert due to arithmetic limitations.

4. This would effectively prevent any further deposits or updates to _totalValue, leading to a denial of service.

Exploit Scenario:

• An administrator deposits a token that behaves abnormally, transferring the entire balance on large input values.

• _balances[token] reaches type(uint256).max, causing all future deposits to revert.

• Withdrawals and other balance-dependent operations may fail due to inconsistencies in _totalValue.

Impact

• Denial of Service (DoS): No further deposits can be made due to the maximum limit being reached.

• Incorrect Accounting: _totalValue no longer accurately represents the treasury’s actual holdings.

• Potential Fund Locking: The contract could become unusable if key functions revert due to balance mismatches.

Tools Used

• Manual Code Review

Recommendations

1. Read Balance Before and After Transfers:

   • Instead of relying on amount, update _balances[token] by calculating the actual transferred amount:

     uint256 beforeBalance = IERC20(token).balanceOf(address(this));

     IERC20(token).transferFrom(msg.sender, address(this), amount);

     uint256 afterBalance = IERC20(token).balanceOf(address(this));

     _balances[token] += afterBalance - beforeBalance;

     _totalValue += afterBalance - beforeBalance;

2. Whitelist Approved ERC-20 Tokens:

   • Restrict deposits to known, standard-compliant ERC-20 tokens to prevent unexpected behavior.

   • Maintain a governance-approved list of supported tokens.

By implementing these mitigations, the Treasury contract can prevent DoS attacks and ensure accurate fund accounting.