Police from eight countries together with several private security companies disrupted the online infrastructure used by cybercriminals to control computers infected with a malware program called Shylock.
Shylock is a Trojan program that first appeared in 2011, primarily targeting online banking. The threat is named after a fictional character in Shakespeare's "The Merchant of Venice" because it includes fragments from the play in its binary files.
Like most malware programs that steal financial information, Shylock is able to inject code into websites in order to capture credentials and trick victims into performing rogue financial transactions. However, the Trojan program has evolved over the years, with its creators adding modules so that it can infect external and USB drives, steal credentials from FTP programs and turn infected computers into proxy servers, among other things.
Security vendor Symantec reported in April 2013 that Shylock was targeting customers of over 60 financial institutions, the majority of them from the U.K., and some from Italy and the U.S.
The law enforcement operation Tuesday and Wednesday seized servers and domain names used by Shylock-infected computers to communicate with each other and the attackers.
The action was led by the U.K.'s National Crime Agency (NCA) and was coordinated from the European Cybercrime Centre (EC3) at Europol. Law enforcement agencies from the U.K., the U.S., the Netherlands, Turkey, Italy, Germany, Poland and France participated. Several IT security vendors, including BAE Systems Applied Intelligence, Dell SecureWorks, Kaspersky Lab and Heimdal Security (part of CSIS Security Group), provided support.
Shylock is believed to have infected over 30,000 computers worldwide, the NCA said in an announcement. The Trojan program has targeted the U.K. more than any other country, but the suspected developers are based somewhere else, the agency said.
Users typically have their computers infected with Shylock after clicking on malicious links that take them to drive-by download exploits or after inserting infected removable drives into their computers.
The NCA and Europol advised users to turn on automatic updates in Windows in order to protect themselves from Shylock. That's because Tuesday Microsoft added detection and removal routines for the threat, which it calls Win32/Caphaw, to its Malicious Software Removal Tool (MSRT). The tool is distributed through Windows Update, but users can also download it directly from the company's website.