In a statement released on its official website, the central bank explained that this fraud is carried out using malware previously installed on the computer of the person making a transfer through online banking, through which "a third party alters the IBAN of the beneficiary's payment account at the time of making that transfer."
The Bank of Portugal explained that if the screen goes static or an update message appears during a transfer, followed by a temporary blockage, it could be an attempt at fraud.