A computer security company has examined the proliferation of illicit programs installed on unsuspecting machines, painting a vivid picture of the international scope of cybercrime.
A zombie computer is one with a hidden software program that allows the computer to be remotely controlled by others. Uses include launching distributed denial-of-service attacks or sending spam without revealing the identity of the culprit. These "backdoors" are often installed with spammed "Trojan horses" or e-mail worms.
In May, researchers with CipherTrust, Inc. found an average of 172,009 new zombies identified each day. Approximately 20 percent of the new zombies originated in the United States and 15 percent originated in China.
An earlier study conducted during late March and early April found that approximately 20 percent of the 157,000 new zombies originated in China. The origin of the zombie machines may change on a daily basis, because machines can be infected anywhere in the world.