The Difference Between Viruses, Spyware, Malware and Adware

The world of “cyber security” is a pretty confusing area, not only are there lots of terms describing similar items, but the big security companies (think Norton, AVG, Trend Micro, etc) use the wrong terms in their products to try and advertise their products! This article is going to clarify the terms a little bit.


Is the term used to describe any software with the intent to do malicious harm to your computer. Viruses, Spyware, and Adware are all types of Malware. Software that slows down or inhibits the use of computer isn't necessarily Malware.


Computer viruses get their name from the viruses us humans get, just like the human viruses, a computer virus will attach itself to a regular (safe) application and will try to distribute itself amongst your computer. That is all a virus is: malware that will try to spread itself.


Spyware is software specifically engineered to “spy” on the infected computer. There are two groups of spyware: marketing and malware. Marketing spyware is safe and is a core part of how Google works. It generally uses cookies to track basic behavior (for example, remembering your last few searches in Google). Malicious spyware is far more invasive than just checking out your recent searches in Google. It has the potential to spy on you using your webcam, look at your banking information, record your keystrokes and more. Spyware is often utilised in identity theft.


Adware is a dying breed of Malware, it is a type of Malware that can do two different type of actions:

Redirect all ads from other platforms to their own ad platform (making them more money) [most people do not consider this "spyware"]
Show ads in other applications of your computer (including the OS itself!)

What are Viruses and why are we scared of them?

Well, to fully comprehend this we must make one thing clear: viruses aren't what people think they are. Malware is the correct term, Malware is any software having the intent to do malicious things to your computer (either hardware or software).

A virus is a particular type of malware that “infects” files and duplicates itself, just like a virus in the human body! It may infect a system file that is run every time the computer turns on, so each time the computer turns on the virus gets activated and can start trying to spread itself more. Like a virus in the human body, the generalised goal of the virus is to survive! It may do other things while it’s there but its primary aim is to survive, so they can be tricky to remove once they get in!

Warning: Your computer may already be infected! Having a virus doesn't mean that anything feels wrong with your computer; the best viruses are smart and silent.

But unfortunately, viruses are the least of our concerns; there are much larger threats out there to our personal lives! Another class of malware is called “spyware” this is software that designed to spy on your computer! Whether it’s something relatively innocent like seeing what websites you go to in order to tailor ads for you, or trying to steal your banking passwords! (That’s bad news!)

Antivirus programs aren't just protecting you against viruses, they are now “anti-malware” software protecting you against a whole range of spyware, viruses, worms, Trojans, root-kits, rabbits, blasters, etc. (there are a lot of them out there).

So how do I get rid of these evil things from my computer and my important files in this brave new world?

Prevention is always better than a cure! As in the medical industry, so in the computer industry. It’s even the same within the construction industry (although they may use slightly different phrasing! :) )

Once you are infected there are a variety of methods of removing malware:

  • Install a decent antivirus and let it do its automatic process
  • Get someone who really knows what they’re doing (a technician) and launch a full investigation
  • There are also standalone utilities to assist with removing malicious software such a Malware Bytes, Autoruns and Process Explorer (less direct).

But getting rid of the malware just isn't enough. Remember me explaining above that the virus will try to survive? Well, it’s designed to survive, and not your system. If you get rid of it, 9 times out of 10 it will have damaged several files; these may be important documents that are now unusable, or important system files. Sometimes the damage is recoverable, but often it is not . You will need to recreate that document or reinstall your operating system!

Okay, this all sounds fairly clear and logical, but what can I do to prevent this happening to me?

There are two important tools in your arsenal. The first one is:

  1. Anti-Malware Software, it’s designed to prevent malicious software from ever entering your system. They are an important second line of defence in the fight against malware

    What, second line of defence? So what is the first?

  2. Common sense. If i’ts too good to be true, it probably isn’t true. Don’t download dodgy applications; “free photoshop” is not a thing. The adult industry is the distributor of aprox 60% of the entire world’s malware. So be careful!

Okay, now I understand how to prevent this happening to me, but why is someone trying to do this in the first place? All I wanted to do was look at cute cats!

Well back in the day (Think Windows 95, 98, the boom of the internet in the 90s), malware was created for fun. It was a challenge and it was funny to see how far you can go! Most of the creators were teenagers or students (back then, it was super easy to create malware :P ) But they grew up, and they had to earn a living. So now malware is more than just the challenge; it is also about making money now to. This is where spyware grew from. This is why there is software designed to steal your banking passwords, view your activity and the like.

There is also a type of malware called a botnet. The way a botnet basically works is: a virus gets distributed and infects as many computers as it can. Each of these computers becomes a “zombie” to be controlled by a “bot”. This type of attack is used to hack into websites anonymously and quickly as they are using everyday people (not their own computer) to coordinate the attack, and they are using hundreds – even thousands – of computers. Things like Google and FBI have been attacked successfully with this approach. Your own computer may be used against the government!

I have a Mac, I’m safe right?

Nope, Macs are just not as popular, and therefore aren’t targeted as often as Windows-based PCs. However, Mac’s themselves are not as secure as Windows. Their “security” is obscurity, and as the experts say “Security through obscurity is no security at all”. In fact, on the launch of Mac OS X Lion it was possible to get the administrator’s password through the terminal with three lines of commands – a five year old could have done it (there goes the parental control, woops :| ). They are not secure, your security is in your own hands.

My computer is doing some weird things. Whenever I try and do a certain thing, an error message keeps popping up, do I have malware?

You could, but the symptoms you’re experiencing are in no way related to malware. Non-malicious software can be just as bad for your system as malware. Most applications aren’t terribly well written. This means that they can be doing stuff to your system that is by no means is malicious, but isn’t something you want. You can run all the scans you want, but you won’t find the application, as technically it’s doing nothing wrong. This does make it harder to find, but not impossible. A smart tech using the right tools for the job can easily find software with odd behaviour.

Error messages are within the same spirit. There can be a setting wrong somewhere causing the error, or there might be a server down that’s causing the error. It could be just poorly written software. Error messages are actually designed to be helpful in getting a resolution. They are important (although not always as clear as we would like :) ).

You said earlier that security companies make “cyber security” confusing, why do you say that?

They call their software Anti-Virus: this is because when most of these companies started, viruses were the only malware around (the term malware hadn't even been coined yet!). Now their software covers a wide range of malware but they still call it anti-virus, when it really should be called anti-malware.

Are there different kinds of Viruses?

You bet! There are all kinds of different viruses, things like:

  • Trojans – Trojans (named for the Trojan horse) pretend to be something else, and drop in a virus later. These are very common.
  • Worms – Worms are a type of virus that attacks through networks
  • RATs – Remote Access Tools give access to your computer without your permission, allowing others to see everything you can see
  • …and hundreds of others!