telephone_complete.md

While this example may be simple, confusing tx.origin with msg.sender can lead to phishing-style attacks, such as this.

An example of a possible attack is outlined below.

1. Use tx.origin to determine whose tokens to transfer, e.g.

function transfer(address _to, uint _value) {
  tokens[tx.origin] -= _value;
  tokens[_to] += _value;
}

2. Attacker gets victim to send funds to a malicious contract that calls the transfer function of the token contract, e.g.

function () payable {
  token.transfer(attackerAddress, 10000);
}

3. In this scenario, tx.origin will be the victim's address (while msg.sender will be the malicious contract's address), resulting in the funds being transferred from the victim to the attacker.