The most common form of Malware is the computer Virus. It’s called a Virus because it spreads by replicating itself. It’s hard to explain the real purpose of Viruses in general, but their main goal is to replicate and doing so cause havoc on a system corrupting programs and data along the way. Each time you start a program with a Virus attached you also start the Virus and if left unchecked it will infect and disrupt the entire system.


A Worm is a program that replicates itself similar to a virus but with the intent to spread itself over a network. Worms always cause harm to a network in some form. They spread through security weakness on the affected network.



This type of Malware does what it says on the tin. It spies on you. Its prime aim is to gather information on you or your organisation without you knowing. Spyware is split into different categories: Adware, Tracking Cookies, System Monitors and Trojans.


Adware is also known as Advertising Supported Software. The purpose of Adware is to show you adverts ranging from popups to banners. Adware can come in a lot of different forms but primarily it will force adverts into places where they should not be.

Tracking Cookies

These are little snippets of information downloaded from websites to your computer. The stored information can be used by other websites and advertisers to see information such as your likes, recent purchases and so much more. Tracking cookies are not harmful by themselves but some people believe them to be an invasion of privacy.


Similar to the Trojan horse in ancient Greek mythology, Trojans are programs that pretend to be something they are not to gain access to your computer. There are a lot of uses for Trojans but more often than not they’re designed to give a back door to the computer allowing somebody to gain access to it when needed.


Rootkits are best described as a group of tools that allow administrator access to a computer. These tools are normally placed on a computer by a hacker who has already gained access to the computer giving then administrator rights on a normal user account.


Keyloggers or Keystroke loggers simply record all keys pressed on a keyboard. Let’s say you go to lloyds.com and then log in the keylogger would have recorded you going there and then your username and password.


A backdoor is a method of bypassing normal authentication or encryption on any device. Default passwords can function as back doors and we see this a lot. Some backdoors are well known and deliberate and might have good/necessary reason to exist.

Browser Hijackers

This type of Malware hijacks your browsers and forces it to show you adverts or change your homepage. If your web browser’s home page changes and you get an increase of adverts you could have a Browser Hijacker.


Ransomware has become more prevalent over recent years, for example the WannaCry attack of 2017. The purpose is to hold your computer for ransom by encrypting all of your files and demanding payment for the access key to read them. Once struck by a ransomware attack, you have few options and some people end up paying the ransom with the hope they will retrieve data.