Zombies are PCs modified by virus or worm programs distributed by spammers. The programs turn them into redistributors of the spam messages they send out. Once a machine is infected, the new zombie awaits instructions from the spammers who operate the zombie networks. Those programs do everything from launch a Denial of Service (DoS) attack to send spam and phishing e-mails through the machine. A network of such zombie PCs creates a spam-sending system which is difficult to identify, locate, and stop.
"The large number of new zombies per day and the percent of them in China is staggering, but really surprising given the number of new Internet users in China," said CipherTrust CTO Dr. Paul Judge. "After all, unprotected computers around the world are vulnerable to compromise within minutes of connecting to the Internet," he added.
CipherTrust also updated its spam statistics and noted that about 57% of spam messages originate in the United States. Although that is down from a recent high of nearly 86%, the United States still ranks highest in terms of spam originations, with South Korea running second at 16%.