Bank hacks in Vietnam and Bangladesh have sparked concerns within global banks, some of which are privately pressing the SWIFT interbank network to shore up security at its 11,000 members.

The pressure on SWIFT comes as new details emerge from the most recently disclosed bank hack. An examination of the malware used in an attack late last year on Vietnam's Tien Phong Commercial Joint Stock Bank shows that unique SWIFT codes identifying at least seven additional financial institutions were embedded in the hackers' work, according to a private report by BAE Systems Plc. 

The list includes major banks in Asia and at least one in Europe, including what two people familiar with the list said were banks where the Vietnamese lender had correspondent accounts. The malware wasn't used to attack those banks, said one person familiar with the situation. Rather, it deleted money-transfer confirmations sent between the Vietnamese bank and its partners that could have alerted bank officials of improper transactions, the person said.