Storm, the Trojan horse that collects PCs into hacker-controlled botnets, roared back into life last month in several waves, security researchers said Monday, and has blown by 2005’s Sober to become the most prolific e-mail-borne malware ever.

“This is the biggest since Sober in mid-to-late 2005,” said Sam Masiello, director of threat research at MX Logic Inc., referring to a long-lasting worm whose variants struck repeatedly in the second half of 2005, often in extremely high numbers. In November 2006, for instance, e-mail filtering companies reported malware-laden e-mail counts spiking 1,500% in a week, and said they were intercepting four times the usual number of infected messages.

Continues at computerworld.com