Worm is a self-contained program (or set of programs) that can spread functional copies of itself or some part of it to other computer systems (usually via a network connection). Note that, unlike common viruses, worms do not need to attach itself to a host program, there are two types of worms: Host worms and network worms. Completely contained within the host computer worm computer they run and use the network connection only copies of itself to other computers, the host computer worm will copy itself into another host, it will terminate itself (thus at any given time, only one copy of the worm running), this worm is sometimes also called "hare," Worm virus holes is generally spread through port 1434. In recent years, a lot of harm such as "Ni Muya" virus is a Worm virus, in January 2007 the popular "Panda" and its variants are also Worm virus. The virus uses the Microsoft Windows operating system vulnerabilities, computer is infected with this virus, it will continue to automatically dial, and use the address information in the file, or a network share to spread, eventually destroy the user's most important data.