zombie

The Kraken botnet, believed by many to be the single biggest zombie network until it was dismantled last year, is staging a comeback that has claimed almost 320,000 PCs, a security researcher said.

Since April, this son-of-Kraken botnet has infected an estimated 318,058 machines - about half as big as the original Kraken was at its height in the middle of 2008, according to Paul Royal, a research scientist at the Georgia Tech Information Security Center.

Like its predecessor, the new botnet is a prodigious generator of spam, with a single machine with average bandwidth able to send more than 600,000 junk mails per day.