The central bank has asked all banks to remain cautious about fraudulent emails, seeking transfer of export payment from foreign buyers.
Bangladesh Bank, in a notice issued on Sunday, said besides documentary collection method, TT (Telegraphic Transfer) system also exists in the country to realise the export payment.
In case of export under the TT method, it has been noticed that foreign buyers were asked to divert payment to different accounts through using false emails with the names of exporters or companies that exported, the notice said.
On November 19, the Bangladesh Garment Manufacturers and Exporters Association (BGMEA) also asked its member factories to remain vigilant of such fraudulent activities by hackers, the association people said.
Three readymade garment makers informed the BGEMA about such incidents in recent months as a few attempts were made to transfer export payments from western buyers by hacking emails of garment exporters.
Three apparel exporters have informed the BGMEA that their email information was hacked and the buyers were asked to transfer export payments to other accounts.
In every case, the hackers used almost same email address with a minimal change of a letter of respective companies, they said.
Bangladesh is particularly vulnerable to cyber attacks.
In early 2016, hackers used fraudulent orders on the SWIFT payments system to steal $81 million, out of $ 1.0 billion requested, from the BB's account at the Federal Reserve Bank of New York.
The reserve money was sent to accounts of a Filipino private bank, RCBC, before landing in the casino industry. So far, only $15 million has been recovered from one of the world's largest cyber heists.
The central bank has already filed a suit against RCBC to recoup losses.