MessageLabs researchers report that more than 40 percent of all spam comes from a single network of computers.

"The Rustock botnet has shrunk since April, when about 2.5 million computers were infected with its malicious software that sent about 43 billion spam e-mails per day," writes Computerworld's Jeremy Kirk. "Much of it is pharmaceutical spam."

"Now, about 1.3 million computers are infected with Rustock, and the botnet is making up for its decreased size with increased volume, said Paul Wood, a MessageLabs intelligence analyst with Symantec," Kirk writes.

Click here to read the Computerworld article.

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