Welcome to our definitive page on virus terms

Written and compiled by the editorial team at expert8.com

What are Computer Viruses, Worms, Trojans, Spyware, Malware, Adware, Bugs, Spam and XXX Diallers?

People are confused over the many types of computer viruses found today. Many of them have different names but function in a similar manner. In order for the average computer user to better understand the dynamics of protecting their personal computers, they first need to familiarize themselves with the common names of the threats and know the difference. The following definitions are written in a simple and concise manner without any technical terms for the benefit of most computer users.

Virus

In computer terminology, a virus is a program that is able to replicate itself and multiply just like a biological virus. It begins by ‘infecting’ its host, usually another program that’s healthy and causes it to behave in a different manner. Viruses, in a broad sense, also refer to malicious software, worms and Trojan horses. Viruses basically need to attach itself to another executable program to work and it can only damage software but not hardware.

Worms

Computer worms have evolved from the basic virus and it’s more widespread today. It’s self-replicating like a virus but it does not need to attach itself to another program for it to work. They are self-contained and can reproduce by themselves, sending copies of itself to other computers without any intervention. Because of this, worms are very dangerous to computer networks as it can spread very quickly and cause untold damage.

Trojan Horse

Trojans in short, is a malicious program disguised as legitimate software. Like its namesake from the classical Greek story, it’s designed to fool the target into thinking it’s useful and harmless. Once a Trojan gains access into the targeted computer and is executed by its unsuspecting user, the attack begins. The objective of a Trojan is usually to provide a back door access to hackers/intruders to control the computer for malicious intent while their identity/location remains hidden. They may also contain ‘spying’  functions where they collect information from the computer. However, Trojans do not self replicate and spread by itself, it needs the user’s action to be executed.

Spyware

Spyware is a general term for a broad range of discreet software designed to monitor and intercept information going through a computer's operation without the consent of the owner. Spyware exists for commercial benefits. It usually monitors surfing habits for marketing purposes and delivers unsolicited pop-up advertisements. The more malicious spyware may hijack your browser and lead you to sites you don’t want to go or even steal your personal information such as your passwords and credit card numbers. Spyware does not replicate and spread itself like viruses and worms. It usually targets only the computer that it has infected.

Adware

Adware are programs that function like spyware but are not malicious. Adware is usually bundled or integrated together with useful software that is offered free or for a very low price. The cost of producing and distributing these types of software are subsidized by marketing companies that see an opportunity in advertising directly to these users. They are usually downloaded into the computer with the user’s consent.

Some adware also take the form of a ‘shareware’, a term used to describe trial or demo software. Users are reminded frequently to pay for a licensed copy to remove the advertisements displayed or to pay for more complete features of the software.

Adware can also be confused with Spyware since some functions of the adware may collect personal information, track user’s activity and provide reports for third parties. However, adware advocates maintain this is done with the user’s consent since they agreed with the “Terms & Conditions of Use” prior to the software being downloaded.

Malware

Malware, as its name suggest, is software with malicious intent. All software or programs that are designed to infiltrate, steal or cause damage to computer(s) fall under this category including all the other programs described above. However, malware should not be confused with defective software; software which is legitimate but contains errors or bugs.

Bugs

A software bug is a flaw in the program’s source code usually caused by mistakes of human programmers, causing the software to produce incorrect results. Bugs in your computer software can sometimes be exploited by hackers or intruders to be used as a ‘back door’ to access your computer. When bugs are detected after the software has been released, the software developer usually solves the problem by distributing free “Patches” or upgrades to be downloaded.

Spam

Spam is the electronic equivalent of the traditional ‘junk’ mail that people get in their letterboxes. Spamming happens when a marketer sends email in bulk directly to unknowing multiple recipients without their consent, hoping to get a response to their advertising message. In short, the definition of spam is the sending of unsolicited bulk commercial email. However, emails that are sent out to multiple recipients who are customers of the marketer and belong to a list of subscribers or an opt-in list are not spam. These recipients know the sender and has agreed to receive further information and offers about the product or service.

Although the spamming method of advertising is generally not intended to harm, it has become quite a nuisance to worldwide Internet users since the new millennium. That’s why many antivirus software now includes spam filters to help users differentiate the emails they want to read from the ones they don’t. Non-commercial emails like pitches from charitable organizations, political parties and religious denominations are not considered spam even though unsolicited.

XXX Dialer

These are dialer programs that contain malicious codes causing computers and modems to disconnect from their local ISP provider and reconnects them to a premium number usually located overseas. They usually infect computers from voluntary downloads when viewing pornographic websites. They don’t advertise themselves as a dialer program but entices viewers with tempting names for them to click on. Once executed inside your computer, you may find yourself receiving a hefty phone bill later. They’re extremely difficult to remove and the XXX icons or pictures may pop-up on your screen every time you start-up your computer. These programs may also arrive in your mail box as spam with a ‘sexy’ attachment for you to open. Once you do, the trouble begins.

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