The most common threat to an organization is computer viruses or malware. A computer can become infected with a virus through day-to-day activities such as browsing web sites or emails. As browsing and opening emails are the most common activities performed by all users, computer viruses represent the most likely risk to a business.
Common examples of malware include viruses, worms, trojan horses, and spyware.
Viruses, for example, can cause havoc on a computer's hard drive by deleting files or directory information. Spyware can gather data from a user's system without the user knowing it. This can include anything from the Web pages a user visits to personal information, such as credit card numbers.