Cybercriminals use Trojans and money mules to loot online bank accounts

Finjan unveiled new research which uncovered new techniques used by cybercriminals to rob online bank accounts.

The techniques described in this report looks like the start of a new trend that is expected to grow. These techniques add functionality aimed to minimize detection by traditional anti-fraud technologies in use by banks.

Research shows how a cybergang used a combination of Trojans and money mules to rake in hundreds of thousands of Euros and to minimize detection by the anti-fraud systems used by banks.

The cybercriminals used compromised legitimate websites as well as fake websites, utilizing the crimeware toolkit LuckySpoilt to infect visitors. After infection a bank Trojan was installed on the victims’ machines and started communication with its Command & Control (C&C) server for instructions.

These instructions included the amount to be stolen from specific bank accounts and to which money mule accounts the stolen money should be transferred. Furthermore, the Trojan forged onscreen bank statements concealing the true transaction amount to dupe the account holders and their banks.

The cybercrime intelligence report covers the following:

• Cybercriminals use sophisticated crimeware tools to steal money online and avoid detection
• They use compromised legitimate websites as well as fake ones to infect visitors with their crime toolkit
• Once infected, the Trojans get instructions from its Command &Control center to rob bank accounts
• Instructions include criteria for the amount that should be stolen from an individual account
• This method is a highly-effective, “Anti anti-fraud” system detection tool
• Once the money is stolen, the Trojan creates a forged bank statement to hide the theft
• The stolen money is transferred to a money mule account and then forwarded to the cybercrooks to prevent any direct money trail
• The cybergang was able to steal Euro 300,000 in 22 days.

"Cybercriminals continue to follow the money, with bank accounts steadily remaining a favourite among their targets. To avoid detection, cybercriminals continue to improve their methodologies for stealing money and going under the radar from the victims and banks alike. With the combination of using sophisticated Trojans for the theft and money mules to transfer stolen money to their accounts, they minimize their chances of being detected,” said Yuval Ben-Itzhak, CTO of Finjan.

Money mule accounts are legitimate bank accounts owned by legitimate bank users. Cybercriminals hire ‘mules’ by falsely telling them they are working for a legitimate business. These bank account owners or “mules” are normally unaware that they are “muling” stolen money, but think that they are being paid for “working from home” and other moneymaking schemes.

To avoid warning signs by anti-fraud systems at the bank, the money mule accounts are only used for a limited number of times within a certain timeframe. Since banks monitor large bank transfers, the amount of money deposited in a money mule account is predefined in order to stay under the radar.

The report shows in detail how this cybergang worked and provides recommendations how individuals and banks can protect themselves.