CA researchers report that, after 18 months' absence, the Storm botnet is back.

"Storm -- once responsible for churning out 20 percent of the world's spam -- started to peter out in September 2007, when Microsoft targeted it through the Malicious Software Removal Tool," writes The Register's Dan Goodin. "Some 274,372 demonized PCs were exorcised during the first month alone. A year later, researchers from Marshal declared the menace dead."

"Now, security watchers at CA say they've spotted a new botnet that bears the hallmarks of Storm and is sending out a 'massive volume of spam emails to targeted recipients,'" Goodin writes.

Click here to read the article at The Register.