Backd contest - antonttc's results

Lines of code

https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/vault/EthVault.sol#L28

Vulnerability details

Impact

User funds can be locked by using a smart contract wallet with inefficient callback, or by future hardforks that change the gas consumption.

address.transfer has been suggested to deprecate by most auditors, because of the potential OOG error. However, payable(address).transfer is still use heavily through out the codeabase.

Reference: https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/

Recommended Mitigation Steps

use call instead:

(bool success, ) = msg.sender.call.value(amount)("");
require(success, "Transfer failed.");

Lines of code

https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/access/RoleManager.sol#L155

Vulnerability details

Impact

The function doesn't remove the address from _roleMembers[role] set, which will mess up with the roleCount

Proof of Concept

Tools Used

Recommended Mitigation Steps

_roles[role].members[account] = false;
_roleMembers[role].remove(account);

Lines of code

https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/oracles/ChainlinkUsdWrapper.sol#L56

Vulnerability details

Impact

The current code returns the following:

return (roundId_, (answer_ * _ethPrice()) / 1e8, startedAt_, updatedAt_, answeredInRound_);

If we're wrapping an asset that's relatively stable to eth price, the answer here might not be updated constantly. By returning the startedAt of the last answer update, it's possible that this answer be considered "stale" from the protocol.

Recommended Mitigation Steps

It's better to return the new updatedAt_ at the greater of the two:

• updatedAt_ from eth oracle,
• updatedAt_ from the asset oracle

This way, if asset/eth is unchanged for a while, but there's a eth price move, we capture the correct updatedAt timestamp