Information, Computer and Network Security Terms Glossary and
Worms are malicious software applications designed to spread via computer networks. Worms are one form of malware along with viruses and trojans. A person typically installs worms by inadvertently opening an email attachment or message that contains executable scripts. Once installed on a computer, worms spontaneously generate additional email messages contaning copies of the worm. They may also open TCP ports to create networks security holes for other applications, and they may attempt to "flood" the LAN with spurious Denial of Service (DoS) data transmissions. Worm can easily penetrate most firewalls and other network security measures, and propagate a complete working version of itself onto other hosts on a network, and may consume computer resources destructively.