Bank Negara Malaysia reported that the attackers were disguised in order to send SWIFT money transfer orders. However, the Bank can stop the transfer of those funds immediately.
There is no information on who was behind the transfer of these messages. And the source of the text from any bank. But the Central Bank of Malaysia confirmed that the network server and the banks themselves were not hacked.
Hacking bank via the SWIFT network was first reported in 2016 and the World Bank was attacked continually.