Affine Labs security record

The Harvester may disrupt the accounting of `queuedShares` and can call `EigenDelegator.completeExternalWithdrawalRequest()` to complete a withdrawal without subtracting the withdrawn amount from the `queuedShares` variable. This results in an overrepresentation of the remaining `queuedShares` in the system, and more critically, the `UltraLRT.totalAssets()` function which determines the value of each share. As it would overreport the number of assets in the system, shares would redeem more assets than they should, potentially leaving the Vault insolvent.

The `AffineDelegator` implementation includes the modifier `onlyVaultOrHarvester()`, which checks if the `msg.sender` is the vault or the harvester for several functions. However, the `UltraLRT` vault contract has its own variables for accounting changes to the delegators. If the delegators are changed without going through the vault functions, this can lead to accounting errors. 1. The `UltraLRT.delegateToDelegator()` function updates the `delegatorMap` and `delegatorAssets`. If the harvester calls `AffineDelegator.delegate()` directly, these updates will not be recorded. 2. The `UltraLRT._getDelegatorLiquidAssets()` function records the balances of `delegatorAssets` and `delegatorMap`. Similarly, if the harvester calls `AffineDelegator.withdraw()` directly, these changes will not be recorded. In the second case, `delegatorAssets` will not record the change from the `withdraw()` function, causing `totalAssets()` to falsely assume it has more assets than it actually does. This discrepancy will result in an incorrect conversion rate of shares to asset amounts.

The `UltraLRT` and `WithdrawalEscrowV2` contracts include a mechanism that triggers `_liquidationRequest()` when an epoch ends via the `UltraLRT.endEpoch()` function. This function requests withdrawals from the delegators back to the `UltraLRT` contract to fulfill the withdrawal requests queue in the `WithdrawalEscrowV2` contract. However, in the `UltraLRT` contract, the `HARVESTER` can continuously call the `delegateToDelegator()` function before `resolveDebt()` is executed, thereby blocking users from withdrawing from the system.

Some parts of the code ignore the return value of the generic ERC20 transfer call. The `transfer` and `transferFrom` functions of ERC20 tokens can return false to indicate a failed transfer instead of reverting directly. Consequently, a failed transfer might occur without being detected. Historically, some ERC20 tokens, such as USDT, do not return the expected boolean value, necessitating the use of safe transfer wrappers. 1. `AffineDelegator.delegate()`: The line `asset.transferFrom(address(vault), address(this), amount)`. 2. `UltraLRT._withdraw()`: The line `IERC20MetadataUpgradeable(asset()).transfer(receiver, assetsToReceive)`. Although the protocol currently integrates only with stETH, which does not pose this issue, future integrations with other tokens might require attention to this concern.