Ethena Labs - nuthan2x's results

<a name="LOW-1"></a>[LOW-1] USDe::constructor ownership transfer for first time in constructor is not implemented on Ownable2Step method

• Initial ownership transfer should be done in Ownable2Step method, but directly transferred in constructor
• First call transferOwnership(admin) then from admin key, call acceptOwnership()
• Severity : Low
• Likelihood : Medium

Recommended Mitigation Steps

-  _transferOwnership(admin);
+  transferOwnership(admin);

<a name="LOW-2"></a>[LOW-2] StakedUSDe.rescueTokens() transaction fails if token == stUSDE && to == address with FULL_RESTRICTED_STAKER_ROLE

• Severity : low
• Likelihood : low

Recommended Mitigation Steps

• So either improve your backend to do all the checks, signature replays etc., Or change the way EthenaMinting.setDelegatedSigner(address) is implemented in 2 step process like ownable2step.
• So the delegated EOA sould accept the delegation and then only can be a delegate.
• Second mitigation requires introducing new storage and a new function to accept delegation.

  function rescueTokens(address token, uint256 amount, address to) external onlyRole(DEFAULT_ADMIN_ROLE) {
    if (address(token) == asset()) revert InvalidToken();
-    IERC20(token).safeTransfer(to, amount);
  }

  function rescueTokens(address token, uint256 amount, address to) external onlyRole(DEFAULT_ADMIN_ROLE) {
    if (address(token) == asset()) revert InvalidToken();
+   if (address(token) != address(this) && !hasRole(FULL_RESTRICTED_STAKER_ROLE, to)) {   
+     IERC20(token).safeTransfer(to, amount);
+   }
  }

<a name="LOW-3"></a>[LOW-3] StakedUSDe._beforeTokenTransfer can be frontran by a bot.

• Scenario:
  • whenever a BLACKLIST_MANAGER_ROLE makes a tx, it can be searched via mempool and a bot with approval of the (to be blacklisted)'s address will transfer the funds to the delegate already set. Or a owner with key can run a bot to frontrun it.
  • Low likelyhood, should be soled when tx'ns of blacklist manager are sent to flashbots builder.
• Severity : low
• Likelihood : Med

<a name="GAS-1"></a>[GAS-1] EthenaMinting::_setMaxRedeemPerBlock() Gas inefficient due to additional warm sload and memory expansion.

Impact

• In EthenaMinting._setMaxMintPerBlock(), there is a new local variable oldMaxMintPerBlock is declared to cache the storage to emit later after updating it.
• But it can be avoided and by emitting the params and storage before modifyng the storage. It is implemented at gas efficiently at SingleAdminAccessControl._grantRole, but missing at EthenaMinting._setMaxRedeemPerBlock() & EthenaMinting._setMaxRedeemPerBlock()

Recommended Mitigation Steps

• In EthenaMinting._setMaxRedeemPerBlock() function

  function _setMaxRedeemPerBlock(uint256 _maxRedeemPerBlock) internal {
-    uint256 oldMaxRedeemPerBlock = maxRedeemPerBlock;
    maxRedeemPerBlock = _maxRedeemPerBlock;
-    emit MaxRedeemPerBlockChanged(oldMaxRedeemPerBlock, maxRedeemPerBlock);
  }

  function _setMaxRedeemPerBlock(uint256 _maxRedeemPerBlock) internal {
+   emit MaxRedeemPerBlockChanged(maxRedeemPerBlock, _maxRedeemPerBlock);
    maxRedeemPerBlock = _maxRedeemPerBlock;
  }

<a name="GAS-2"></a>[GAS-2] EthenaMinting._deduplicateOrder(), update the state only if valid== true.

• valid is validated after updating storage, so if valid == false, then its a gas inefficient.

Recommended Mitigation Steps

• In EthenaMinting._setMaxRedeemPerBlock() function

  function _deduplicateOrder(address sender, uint256 nonce) private returns (bool) {
    (bool valid, uint256 invalidatorSlot, uint256 invalidator, uint256 invalidatorBit) = verifyNonce(sender, nonce);
-    mapping(uint256 => uint256) storage invalidatorStorage = _orderBitmaps[sender];
-    invalidatorStorage[invalidatorSlot] = invalidator | invalidatorBit;
    return valid;
  }

  function _deduplicateOrder(address sender, uint256 nonce) private returns (bool) {
    (bool valid, uint256 invalidatorSlot, uint256 invalidator, uint256 invalidatorBit) = verifyNonce(sender, nonce);
+    if(valid) {
+        mapping(uint256 => uint256) storage invalidatorStorage = _orderBitmaps[sender];
+        invalidatorStorage[invalidatorSlot] = invalidator | invalidatorBit;
+    }
    return valid;
  }