Cybercrooks swiped £30 million (€36m) from the banks accounts of 30,000 customers in Italy, Germany, Spain and Holland over the summer using an elaborate mobile banking fraud scam.
The malware-based attack targeted both corporate and private banking users, performing automatic transfers that varied from €500€ to €250,000 to intermediary accounts controlled by members of the gang. The fraud used malware based on the infamous ZeuS cybercrime toolkit to target the PCs and mobile phones of banking customers. It circumvented SMS messages used by banks to secure customers’ account logins and authenticate transactions, according to firewall and security tools firm Check Point.
The attack worked by infecting victims’ PCs and mobiles with a modified version of the Zeus trojan. When victims attempted online bank transactions, the process was intercepted by the trojan. Under the guise of upgrading the online banking software, victims were duped into giving additional information including their mobile phone number, infecting the mobile device. The mobile Trojan worked on both Blackberry and Android devices, giving attackers a wider reach.
With victims’ PCs and mobile devices compromised, the attackers could intercept and hijack all the victims’ banking transactions, including the key to completing the transaction: the bank’s SMS to the customer containing the ‘transaction authentication number’ (TAN). With the account number, password, and TAN, the attackers were able to stealthily transfer funds out of victims’ accounts while victims were left with the impression that their transaction had completed successfully.
Customers at an estimated 30 banks fell victims to the cyberheist. The so-called Eurograbber attack began with infecting victims PCs with a modified versions of the ZeuS Trojan before hijacking bank sessions online to trick victims into handing over their mobile number. Fraudsters then sent links to download a modified version of the Zitmo (Zeus in the mobile) malware to marks under the guise of an "online banking security update". This step allow hackers to authorise fraudulent transactions while all the while keeping victims unaware that anything had gone wrong.
The scam was discovered by Check Point and Versafe, a private developer of security applications. Affected banks have been notified. The two security firms are working with law enforcement to block the attacks.
Check Point and Versafe got involved because they were asked to investigate a spate of unusual transactions from bank accounts, and started tracing the routes and IP addresses involved in those transactions. This uncovered the Zeus infections and the attack process, leading them to notify the affected banks and law enforcement.
"Cyberattacks are constantly evolving to take advantage of the latest trends," said Gabi Reish, head of product management at Check Point Software Technologies. "As online and mobile banking continue to grow, we will see more targeted attacks in this area, and Eurograbber is a prime example.”
Eran Kalige, head of security operation centre, Versafe, added: “As seen with Eurograbber, attackers are focusing on the weakest link, the people behind the devices, and using very sophisticated techniques to launch and automate their attacks and avoid traceability.” ®