IBM researchers have discovered a clever new use of the Citadel malware platform, a descendant of the Zeus Trojan, to deliver ransomware that poses as the U.S. Department of Justice and hijacks victims’ computers. This ransomware, called Reveton, freezes the compromised machine’s operating system and demands $100 to unlock it.

Reveton was observed a few weeks ago being used as a standalone attack, but it has now been coupled with the Citadel platform. This is another example of financial malware expanding beyond online banking fraud and being used as a launchpad for other types of cyber attacks. Citadel is able to target employees to steal enterprise credentials, and in this example, it targets victims directly to steal money from them rather than their financial institution.

How Does Reveton Work?

The attack begins with the victim being lured to a drive-by download website. Here, a dropper installs the Citadel malware on the target machine, which retrieves the ransomware DLL from its command-and-control center.

Once installed on the victim’s computer, the ransomware locks up the targeted machine and displays a warning message notifying the user he or she has violated U.S. federal law. The webinject screen (below) claims the infected machine’s IP address was identified by the Computer Crime & Intellectual Property Section as having visited websites that contain child pornography and other illegal content.

In order to unlock the computer, the victim is instructed to pay a $100 fine to the U.S. Department of Justice using prepaid money card services. The payment service options presented to the victim are based on the geographic location of his or her IP address. For example, users with U.S. IP addresses must pay using MoneyPak or Paysafecard.

Citadel Platform Persists

Independent of the Reveton ransomware secondary payload, Citadel continues to operate on the compromised machine on its own. Therefore, it can be used by fraudsters to commit online banking and credit card fraud by enabling the platform’s man-in-the-browser, keylogging and other malicious techniques.

It is clear from this and similar attacks we have discovered recently that financial malware has achieved a technological level of sophistication that enables it to carry out virtually any type of cyber attack. Through a combination of social engineering, data capturing and communication tampering, these attacks are being used by criminals to target applications, systems and networks that belong to financial institutions, enterprises and government agencies to commit fraud or steal sensitive information. It is important to recognize that now, more than ever, cyber crime and cyber security protection begins with the endpoint.

2014 Ponemon Study: The Economic Impact of Advanced Persistent Threats (APTs)