"The United States is now home to the largest percentage of botnet-infected computers, hosting 18 percent of all zombie machines. Cybercriminals are building an army of infected, "zombie" computers to recover from last November’s takedown of a central spam-hosting ISP, according to the new report from Avert Labs.
"The November 2008 takedown of McColo Corp. dropped spam levels by an estimated 60 percent, but spam quantities are rising as cybercriminals create new ways to send bulk e-mails.
"The quick expansion of botnets threatens to boost spam levels back up. In fact, spam volumes have already recovered about 70 percent since McColo Corp. went offline. Compared with the same quarter a year ago, spam volumes are 20 percent lower in 2009 and 30 percent below the third quarter of 2008, which had the highest quarterly volumes recorded to date."
