SWIFT, the global financial messaging network that banks use to move billions of dollars every day, warned on Thursday of a second malware attack similar to the one that led to February's $81 million cyberheist at the Bangladesh central bank.

The second case targeted a commercial bank, SWIFT spokeswoman Natasha de Teran said, without naming it.

SWIFT said in a statement that the attackers exhibited a "deep and sophisticated knowledge of specific operational controls" at targeted banks and may have been aided by "malicious insiders or cyber attacks, or a combination of both."

The organization, a Belgian co-operative owned by member banks, said that forensic experts believe the second case showed that the Bangladesh heist "was not a single occurrence, but part of a wider and highly adaptive campaign targeting banks."