Safety is a major concern in today's world as the world has become increasingly complex and accessible, especially through Internet and email. One of the most important issues facing people in security today is in relation to computers. Most security issues relating to computer viruses and worms, Trojan horses, and the like, are geared toward the PC consumer market.

Ranging from running the adware, browser hijackers, infecting computers with malware and spyware programs running massive spam emails, acting as servers, completely overcome computers, steal personal information, including social security numbers and identity personal information of residence, age, demographics, and credit card and banking information, the execution of pornographic material and advertisements, the amount and variety of spyware and adware threats posed safety problems to computers, have aggravated In recent years, exploiting the increased safety violations.

One of the most prevalent shutters through firewalls and security systems, is the worm. Defined in the Oxford dictionary as a self-replicating program that can spread through the network, usually has a detrimental effect. Computer worms primarily replicate on networks, but they represent a subclass of computer viruses. With the wide variety of computer worms and viruses, researchers differ on the exact definitions of the worms.

The infection strategy oriented network is in fact a major difference between viruses and worms. Moreover, the worms do not need to infect files but propagate as standalone programs. Additionally, several worms can take control of remote systems without the aid of users, usually exploiting a vulnerability or set of vulnerabilities.

Each worm has some essential components, such as the destination locator and propagator modules of infection and some other nonessential modules, such as remote control interface update, director of the life cycle, and load routines useful. The worm must be able to find new targets to spread rapidly in the network. Most worms search your system to discover the email addresses and simply send copies of themselves to address such a convenient system for attackers seeking to enter into a corporate firewall. Most companies usually need to allow email messages through corporate firewalls, allowing an easy penetration point for the worm. Many worms deploy techniques to explore the network of nodes in the level of research and even "fingerprint" of the remote system to check whether the system could be vulnerable.

Another important component of a worm is remote control via a communication module. Without a module, the worm's author can not control the worm network by sending control messages from copies of the worm. An update or plug-in interface is an important feature of advanced worms to update the worm's code on a system, already committed.

The attacker is interested in changing the behavior of the worm, and even sending new infection strategies involved nodes as much as possible. The rapid introduction of new vectors of infection is especially dangerous. Many worms have bugs in your component life cycle manager and continue working without stopping.