Access control : wrongly setting the new guardian address to governance address

[code423n4]

Handle

ksk2345

Vulnerability details

Impact

Impact is high; once a new guardian is set using 'setGuardian' function, the new guardian is in full control of the contract, due to this bug. The setGuardian function mistakenly sets the governance address instead of setting it to guardian.

Proof of Concept

Issue found in two contracts

1. Ref : https://github.com/Badger-Finance/badger-ibbtc-utility-zaps/blob/a5c71b72222d84b6414ca0339ed1761dc79fe56e/contracts/SettToRenIbbtcZap.sol
   line 130 : function setGuardian

2. Ref : https://github.com/Badger-Finance/badger-ibbtc-utility-zaps/blob/6f700995129182fec81b772f97abab9977b46026/contracts/IbbtcVaultZap.sol
   line 116 : function setGuardian

   function setGuardian(address _guardian) external {
   _onlyGovernance();
   governance = _guardian;
   }

Wrongly setting governance address which is meant to set new guardian address

Tools Used

Manual review

Recommended Mitigation Steps

Change as below in both the contract's setGuardian function

function setGuardian(address _guardian) external {
    _onlyGovernance();
    guardian = _guardian;
}

[0xleastwood]

duplicate of #51