This is the first of a three part series on computer viruses. We will define what different types of viruses are, what they can do, how to remove them, and how you can prevent future infections.
Adware – A small software program, typically installed when visiting certain internet websites, or installing “shareware” or “freeware” software. Adware can monitor websites that you visit, and transmit that information to marketers for research and targeted advertising. It can increase the delivery of advertisements in the form of pop-up ads, targeted banners, etc.
Malware – Malicious software that is installed without your knowledge, that is used for sinister purposes, such as gathering information like passwords, installing viruses and trojans, turning a computer into a “Zombie”, and other unwanted actions.
Spyware – Again, software installed on your computer without you knowing. Spyware can be software installed by an owner of the computer to monitor the activities. For example, a parent that installs software to log the keystrokes of their kids, or a business owner monitoring their employee’s computer use. Spyware can monitor internet activity, and can also re-direct users to specific websites.
Trojan (Horse) – One of the more riskier malware programs, a trojan horse virus typically starts out as a small program that seemingly causes no harm, but can give others unauthorized access to your computer system. They are usually not self replicating, like viruses and worms, and they do require interaction with an outside party, like a hacker.
Virus – A virus is a program or set of scripts that can cause harm to your computer by deleting or corrupting files, disabling security software and other problematic things. A virus is typically a local program, and can be spread through manual processes, like sharing flash disks or USB drives, as well as email, IM programs, and social networking websites. The term virus is generally used as a blanketed description for other types of infections, like trojans, spyware and malware.
Worm – A self-replicating program that spreads through networks, e-mail, instant messaging programs and file sharing. Worms do not usually attach themselves to other programs. Many worms do not typically cause damage to files or programs, however, they can cause problems with bandwidth because of how they spread and replicate.
Zombie (Computer) – A computer that is connected to the internet, and has been compromised by a trojan, virus or worm. The computer is then used by someone controlling it, to send out spam e-mails, spread viruses, attack websites, etc. The owner of the computer does not know their computer is being used in that way. An estimated 80-90% of all spam e-mails sent worldwide comes from zombie infected computers.