Ukranian police on Thursday arrested five people thought to be the brains behind the Zeus malware.
The operation is part of an ongoing effort to take down a criminal empire that stole $70 million [m] from victims' bank accounts over the past few years. Many of those hit were small businesses or local organizations that ended up having to absorb the costs of the fraud.
Ukraine's national police force, the SBU, made the arrests as part of a joint effort with the U.S. Federal Bureau of Investigation, police in the Netherlands and the U.K.'s Metropolitan Police Service. Those detained are "key subjects responsible for this overarching scheme," the FBI said in a statement.
Ukranian SBU agents also executed eight search warrants in an operation that was manned by about 50 police officers.
Zeus is considered to be the most lucrative piece of malware ever created, and it took a network of operatives to manage the operation. On Tuesday, the Metropolitan Police Service arrested 20 people, and that was followed up by more arrests in the U.S. on Thursday. Both operations dismantled the "money mule' system used to move funds overseas.
The operation -- named Trident Breach -- was launched in May 2009 after FBI agents in Omaha, Nebraska, began investigating a computer fraud case that involved 46 unauthorized payments made to different bank accounts across the country. This type of fraud is the trademark of the Zeus network. In a typical Zeus theft, the criminals hack into the victim's online bank account and then move money out using the banking system's automated clearing house (ACH) money transfer system.
"The cyber thieves targeted small- to medium-sized companies, municipalities, churches, and individuals, infecting their computers using a version of the Zeus Botnet," the FBI said Friday in a press release. "The malware captured passwords, account numbers, and other data used to log into online banking accounts."
According to the FBI, the scammers tried to steal $220 million [m] in total, and actually managed to move $70 million [m] offshore.