Published under Glossary

What is "Malware"

The word Malware is derived from the term 'Malicious Software'. Any piece of software that performs undesirable operations such as data theft or some other type of computer compromise can be categorised as Malware. Malware is a broad term that can refer to various types of malicious programs. This document will cover some of the main types of Malware, namely: Trojans, Viruses, Worms, and Spyware. The symptoms caused by these different types of malware may sometimes be similar. However, they mainly differ in the way they spread and infect systems.

How Does it Work?


A Trojan (Trojan Horse) is a type of malware that disguises itself as a legitimate piece of software in order to convince a victim to install it. Once installed, the malware is able to perform its malicious activity in the background.


A virus is a type of malware that attaches itself to a program, file or document enabling it to spread from one computer to another. These viruses can be spread in several different ways. Some common methods of infection are through removable media, from downloads off the Internet, and from e-mail attachments. They can also spread through script files, documents, and cross-site scripting vulnerabilities on the web. It is important to note that a virus requires a human action (such as running an infected program) for it to be spread.


A worm is similar to a virus and is sometimes considered to be a subclass of a virus. Just like a virus, a worm spreads from computer to computer. However, what mainly distinguishes a worm from a virus is that a worm has the capability of spreading without any human action. A worm will usually exploit weaknesses such as OS vulnerabilities or weak passwords in order to spread over computer networks.


Spyware is a type of malware that spies on a users' activities without their knowledge or consent. These spying activities can include keylogging, activity monitoring, and data collection, as well as other forms of data theft. Spyware is usually spread as a Trojan, or by exploiting software vulnerabilities.

Considerations and recommendations

There is no bulletproof approach to avoid ever getting infected with malware. However, there are many precautions that one could adopt that will greatly increase a user's protection from a wide range of malware:

  • Since many different types of malware take advantage of OS and software vulnerabilities it is important to keep software and OS systems up to date with the latest vulnerability patches.
  • Use anti-malware and firewall software to protect your systems. You may want to spend some time researching different anti-malware solutions, and choose one that offers protection against a wide variety of malware types.
  • Keep anti-malware software up to date with the latest malware definitions.
  • Do not download files, programs, attachments, etc. when you are not sure of what the content or original source might be.
  • Only use legitimate sources of software and data.
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