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Ramnit Botnet Disrupted By International Public-Private Collaboration

Europol leads the effort to bring down the bank credential-stealing botnet that infected 3.2 million computers across the globe.

Europol's Cybercrime Centre (EC3), with assistance from Symantec, Microsoft, and Anubis Networks, shut down command-and-control servers and redirected 300 domains used by the Ramnit botnet, used mostly for stealing banking credentials. EC3 announced today that the operation was conducted from The Hague on Tuesday and included representatives from the United Kingdom, Germany, Italy, and the Netherlands.

Ramnit was first discovered in November 2010. Investigators estimate that approximately 350,000 Windows computers (clients and servers) are infected with Ramnit at present, and that it has infected about 3.2 million computers in total over the course of its lifetime. The country hit hardest by Ramnit is India, accounting for 27 percent of the victim machines; Indonesia, Vietnam, Bangladesh, and the United States are next on the list.

This takedown operation continues a trend that began in June with Operation Tovar, the effort to take down the Gameover ZeuS botnet -- an international, public-private collaboration principally aimed at disrupting the crimes, instead of arresting the criminals.

Ramnit also took something from GOZeuS. As Symantec described in a blog post today, Ramnit started out as just a worm, copying tself to removable drives, infecting .exe., .dll, and .html files, and opening backdoors. However, Ramnit has since evolved, using exploit kits to propogate itself, and borrowing modules from the GOZeuS malware.

Ramnit contains six main modules: a drive scanner for finding sensitive files and banking credentials; an anonymous FTP server for maintaing remote access to an infected machine and exfiltrating data from it; a virtual network computing module, also to obtain access; an FTP grabber to gather logins for a larger number of FTP servers; a cookie grabber, to enable attackers to impersonate victims and hijack Web sessions; and a spy module, which not only monitors user's activity, but can also manipulate banks' websites to prompt users to share even more information, like credit card numbers.

It also uses persistence methods: When Ramnit compromises a machine, it copies itself both to the memory and the hard disk. If the malware on the hard disk is eradicated, the one in memory can detect that and re-install the malware on the hard disk.

"This successful operation shows the importance of international law enforcement working together with private industry in the fight against the global threat of cybercrime," said Europol Deputy Director Operations Wil van Gemert, in the statement. "We will continue our efforts in taking down botnets and disrupting the core infrastructures used by criminals to conduct a variety of cybercrimes. Together with the EU Member States and partners around the globe, our aim is to protect people around the world against these criminal activities."

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