Deja Vu: Reincarnated Botnet Struck Down

Researchers at Kaspersky Lab, CrowdStrike, and Dell SecureWorks intercept bots from infamous spamming botnet -- but this time without the help of Microsoft and its legal team
The researchers said the operation to divert the bots began on March 21, when they set up the sinkhole lure. They found flaws in the peer-to-peer architecture that allowed them to inject messages into the botnet that propagated and redirected all of the bots to a sinkhole controlled by CrowdStrike. "They don't see any commands ... we pretend to be one of the peers in the peer-to-peer network. What we do instead of providing a real peer list is create a special peer list of entries to our peer system. We apply special tricks so it gets propagated to other machines," Werner said.

The Kelihos/Hlux botnet operators did try to fight back: They pushed out a new version of their bot software, and halted their spamming and DDoS attacks. But that didn't stop the takeover: The only way they could have prevented the takeover would have been to create an update within 10 to 15 minutes, according to CrowdStrike's Werner.

"Overall, this second sinkholing was very successful," said Marco Preuss, head of global research and analysis in Germany for Kaspersky Lab. "And what was also interesting to us is that this approach shows that peer-to-peer architectures in botnets are not protected from sinkholing."

Now it's up to the ISPs to get their users cleaned up. "We will keep the sinkhole up as long a necessary so no one gets control again," Tillman said. "We are working to take measure to inform the affected ISPs [to contact] their customers. Hopefully, we will see a decrease over time [of infected bots].

"But this is not the ultimate solution. This gang has been in operation since 2007 ... we need changes to legislative systems to [enact] new laws against cybercrime."

Kaspersky has provided an FAQ here on how the researchers disabled the botnet.

[ An emerging botnet based in the Republic of Georgia has caught the eyes of security researchers. See New Botnet Emanates From Republic Of Georgia, Researchers Say. ]

Have a comment on this story? Please click "Add Your Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message.