What You Should Know About Grum and the Botnet Takedown

Grum–the third largest botnet in existence, and the source of nearly twenty percent of all spam traffic online–has been taken offline by authorities. In some ways the takedown is significant, but it may not change much in the grand scheme of things. Let’s take a closer look at the botnet, and what the takedown means for all of us.

Perhaps you’ve heard Grum. I’ll be honest, I hadn’t. But, when a single botnet is responsible for one-fifth of all spam traffic it gets the attention of security researchers and law enforcement agencies. The cooperative, collaborative effort involved in this multi-national sting is impressive in its own right, but don’t expect spam to suddenly stop.

Adam Wosotowsky, messaging data architect at McAfee Labs, doesn’t consider the Grum takedown to be all that significant in the overall history of botnets, however, he still believes the effort is worthy of praise. “I’m not trying to take anything away from it, but I think that this is just one more step in the right direction and that there were many steps to get here and there will be many steps to go. It shows that the “red line” where botnet behaviors trigger a coordinated international response that takes the botnet down is getting more and more aggressive.”

Lamar Bailey, director of security research and development at nCircle, is also impressed with the collaborative effort. He explains, “This takedown is significant because it took place in multiple countries including Russia, Ukraine, Panama, and Netherlands and it happened fairly quickly.”

Bailey says that without a smoothly coordinated effort the cyber criminals could have been tipped off and might have had an opportunity to move the command and control servers to new locations before authorities could act. Apparently the Grum botnet owners tried to do so, but the takedown was handled with such precision that they were unsuccessful.

So, what now? Is the world free from Grum? No, not completely.

Symantec Security Response wants IT admins and users to know that there are still large numbers of infected systems out there–like the hundreds of thousands of PCs still infected with DNSChanger months after the malware was effectively shut down.

A statement from Symantec Security Response explains, “The attackers are still out there as well, so they may attempt to grow a new Botnet. Users should make sure they have good antivirus software installed and kept up to date. Also, users should be proactive about keeping their systems and applications patched with the latest security updates.”

Wosotowsky agrees, pointing out, “Grum only existed in the first place because users didn’t have adequate defenses.”

He also stresses that IT admins should implement detailed tracking and logging of network traffic data. This information may prove invaluable to security researchers and authorities trying to track down and shut down malware attacks.