Server Botnet Hits Unix Boxes

Wednesday, March 19, 2014 @ 02:03 PM gHale


There is a new operation just discovered that has over 25,000 Unix servers suffering from an infection for the past two years.

Called “Windigo” after the mythical creature from Algonquian Native American folklore, the servers are sending out 35 million spam emails each day, putting around 500,000 computers at risk of malware infection.

“Each day over half a million computers are put at risk of infection, as they visit websites that have been poisoned by web server malware planted by Operation Windigo redirecting to malicious exploit kits and advertisements,” said ESET security researcher Marc-Étienne Léveillé.

Most of the infected servers are in the U.S., Germany, France and the UK. Many of the affected servers belong to hosting providers. The list of victims includes companies such as cPanel and kernel.org.

ESET has been investigating the campaign for around one year. In total, 25,000 servers suffered infection, of which 10,000 still have the issue.

Mac users are not out in the cold as Windows users end up directed to malware-serving exploit kits. People who visit the infected websites from Macs end up pushed to adult content or served ads for dating sites.

Léveillé highlights the Ebury backdoor deployed by the attackers doesn’t exploit Linux or OpenSSH vulnerabilities. Instead, it ends up planted manually.

“The fact that they have managed to do this on tens of thousands of different servers is chilling. While anti-virus and two factor authentication is common on the desktop, it is rarely used to protect servers, making them vulnerable to credential stealing and easy malware deployment,” Léveillé said.

Pierre-Marc Bureau, security intelligence program manager at ESET, said they are investigating the campaign because cybercriminal operations that rely on Linux malware are not something we get to see every day, particularly when it comes to an operation as complex as Windigo.

Bureau said this is the biggest botnet of servers they have ever seen. What they do know is the bot masters are very good in programming and the administration of Linux systems. Additionally, they probably have good connections in the underground, considering their capabilities to send spam and install malware.

The complete paper of the Windigo operation is available on ESET’s website.



Leave a Reply

You must be logged in to post a comment.