A bug within the program allowed the worm to multiply across hundreds of network links. This worm reportedly cost millions in man hour times for testing and repair of the systems it affected. A trojan horse is a segment of code written in a program that was not documented by the original programmer. Viruses infect thousands of systems every day, and can potentially cause a significant amount of damage to every system they come in contact with. With the tremendous growth of the World Wide Web, online services, and the amount of electronic media available to people, the threat of contracting a virus on a computer has dramatically increased.
Viruses can cause a significant amount of damage to a system.
According to the National Center for Computer Crime Data in Los Angeles, close to 550 million dollars have been lost to computer crimes. There is not a computer that is completely safe from a virus. Since virus identification and disinfection constantly changes as new viruses are written and evolve, there is not a standardized method to identify computer viruses. Most program viruses attach themselves to some kind of executable file, store itself in memory, and then corrupt the data within the program. Eventually, the virus will spread to other programs where it will corrupt the data within the program, and even change file names.