More than 15,000 Australian credit cards worth an estimated $3.75 million in total were salvaged from underground hacker forums in a global police sting.
The cards were held across 36 carding websites that used automated vending carts to sell the accounts in large batches.
Law enforcement agencies including the Australia Federal Police, the FBI, and the Netherlands national police force investigated the sites and on Wednesday they pounced.
Two men were arrested on suspicion of making large-scale purchases of compromised data from the carding sites, while British anti-fraud police seized computers suspected of being involved in the fraud racket. One operator of an automated vending cart was arrested in Macedonia.
The British serious organised crime unit (SOCA) claimed to have saved some $800 million through its anti-fraud efforts.
It said it had seized some two million pieces of financial and personal information.
Details on the 15,450 compromised Australian cards found by the AFP since October last year were supplied to local banks.
The targeted carding websites now display a message from the US informing visitors that the domains were seized.
“This operation is an excellent example of the level of international cooperation being focused on tackling online fraud,” SOCA head of cyber operations Lee Miles said.