In fact, the old security nemesis -- which was reported dismantled last year -- has compromised more than 318,000 systems, nearly half of the 650,000-node size it achieved at its peak in 2008, according to Paul Royal, research scientist at the Georgia Tech Information Security Center (GTISC), a leading authority on botnet research.
So far the resurrected Kraken is primarily a spam distributor, focusing most of its output on ads for male enhancement and erectile dysfunction, Royal says. The botnet's performance is prodigious: A single node with a DSL-speed connection was detected sending more than 600,000 spam messages in a 24-hour period.
Many popular antivirus tools don't detect Kraken, Royal says. A scan by VirusTotal indicates that none of the top three antivirus tools -- Symantec, McAfee, and Trend Micro -- can detect current Kraken samples, he reports.
The resurrected Kraken is usually installed by another botnet, using botnet malware such as Butterfly, Royal reports. It's not clear whether Kraken installation is handled by the same criminal group as Kraken operations, but it could be an example of specialized criminal groups working together, he suggests.
Kraken's reappearance may indicate a broader trend toward the reuse of code, Royal suggests.
"The recent use of private malcode [e.g., code for Storm, Kraken to form [or re-form] botnets may be indicative of an upcoming trend of malcode reuse," Royal says. "Well-written code, regardless of its intended purpose, takes several iterations to develop and is expensive to replace. Regardless of its age or infamy, as long as malicious code can be placed inside an executable sheath that makes it appear new or unknown to traditional defense-in-depth technologies [e.g., host-based antivirus], even professional criminal gangs will continue to find uses for it."
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