Aggressive Botnet Activities Behind Spam Increase

An anonymous reader writes, "A spam-sending Trojan dubbed 'SpamThru' is responsible for a vast amount of the recent botnet activity which has significantly increased spam levels to almost three out of every four emails. The developers of SpamThru employed numerous tactics to thwart detection and enhance outreach, such as releasing new strains of the Trojan at regular intervals in order to confuse traditional anti-virus signatures detection." According to MessageLabs (PDF), another contributor to the recent spam increase is a trojan dropper called "Warezov."