ancientribe writes “Storm is no longer the world’s largest botnet: Researchers at Damballa have discovered Kraken, a botnet of 400,000 zombies — twice the size of Storm. But even more disturbing is that it has infected machines at 50 of the Fortune 500, and is undetectable in over 80 percent of machines running antivirus software. Kraken appears to be evading detection by a combination of clever obfuscation techniques that hinder its detection and analysis by researchers.”