How Brazilian Steal Billions

Man-in-the-middle attack against a Brazilian payment system:

Brazil has an extremely active and talented cybercrime underground, and increasingly Brazilian organized crime gangs are setting their sights on boleto users who bank online. This is typically done through malware that lies in wait until the user of the hacked PC visits their bank’s site and fills out the account information for the recipient of a boleto transaction. In this scenario, the unwitting victim submits the transfer for payment and the malware modifies the request by substituting a recipient account that the attackers control.

This is the sort of attack that bypasses any two-factor authentication system, since it occurs after all authentication has happened. A defense would be to send a confirmation notice to another device the account-owner owns, confirming the details of the transaction.