Use of Insecure Function
Why is this important?
tx.origin is a global variable in Solidity which returns the address of the
account that sent the transaction. Using the variable for authorization could
make a contract vulnerable if an authorized account calls into a malicious
contract. A call could be made to the vulnerable contract that passes the
authorization check since tx.origin returns the original sender of the
transaction which in this case is the authorized account.
Avoid Using Insecure Function
Option A: Avoid Use of tx.origin
- Go through the issues that GuardRails identified in the PR.
- Identify the code that looks like this:
pragma solidity 0.4.24;
contract MyContract {
address owner;
function MyContract() public {
owner = msg.sender;
}
function sendTo(address receiver, uint amount) public {
/* Note that this the insecure use of tx.origin */
require(tx.origin == owner);
receiver.transfer(amount);
}
}
- Remove the
tx.originand authorize usingmsg.sender()instead. - Test it
- Ship it 🚢 and relax 🌴