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It's (Already) Baaack: Kelihos Botnet Rebounds With New Variant

Botnet hunters debate whether Kelihos/Hlux operators can reclaim rescued bots
Gunter Ollmann, vice president of research at Damballa, says botnet takedowns are a temporary disruption to the operation -- and when it comes to peer-to-peer networks like Kelihos, there's a legal conundrum.

"Like I've said before, if you're going to take down a botnet you have to take out the criminals at the top. It's the only way. Taking out the infrastructure they depend upon for distributing new infectious material and C&C is a disruption technique -- a delaying tactic if you will, and maybe an evidence building process if you're lucky," Ollmann said in a blog post today. "In the case of P2P-based botnets, there's very little infrastructure you can get your hands on -- and you'll probably end up having to issue commands to botnet victim devices -- which is fraught with legal and ethical problems."

[ Microsoft continued its aggressive legal tear against botnets with a new operation for which the software giant successfully seized some command-and-control (C&C) servers run by cybercriminals using Zeus and its related crimeware. See Microsoft, Financial Partners Seize Servers Used In Zeus Botnets. ]

And even if security vendors are able to successfully knock out a C&C infrastructure, it's meaningless unless they also remove the infection vector, according to Ollmann. "Even if you're lucky enough to be able to take out the C&C infrastructure or mechanism of communication, if you don't take out the infection vector -- the mechanisms of distributing new crimeware variants -- you've achieved very little. As evidenced by the most recent Kelihos botnet takedown attempt, the criminals retained their primary distribution system and are already accumulating thousands of new victims per day with their latest Kelihos-variant campaign," he wrote.

Kaspersky's Preuss, meanwhile, maintains that even a temporary shutdown of a botnet is helpful in the fight against botnets. "It would be naive to believe they would not continue to create new botnets for malicious use. Our sinkholing operations for Hlux A and B have shown that our countermeasure efforts are successful, even if it's just a temporary way to slow the group down," he says.

But the big prize is the bad guys, he notes. "The only way to permanently shut down botnets is to arrest and prosecute the creators and groups operating them. This is a difficult task because security companies encounter different federal policies, jurisdictions, and legal processes in various countries where botnets are located. This causes the law enforcement investigations and legal process to be a long and arduous process," Preuss says. "The only way to accelerate this process is by having more international law passed that supports closer collaboration between cybersecurity professionals, law enforcement, and legal systems."

Meanwhile, Seculert reports that the majority of the infected Facebook users are from Poland and the U.S. -- a trend that was seen with the machines Kaspersky and CrowdStrike grabbed. Some 54 percent of the Facebook infections are in Poland, and 30 percent in the U.S., according to Seculert.

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