The biohazard symbol, that also represents malware.

Malware, a portmanteau of the two words malicious and software, is a piece of dangerous software that is designed to infiltrate and damage a computer system without the owner's informed consent. Several types of malware exist out there.

The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code. They can be combated by using antiviruses or other programs used to remove malware. It can sometimes cause bugs and glitches. All the malware out there has caused over hundreds of billions of dollars worth of damage altogether.

Despite popular belief, "malware" is generally the universal term for malicious code, and "virus" is just a subcategory of it.

The user's computer can be affected by worms, regular viruses and malware, trojans, bloatware, ransomware, adware, hackers, phishing, spyware, etc. The user should get an antivirus software to remove it. The user may also receive a death screen from it if it causes their computer to crash or become unstable.


The current version of the Blue Screen Of Death.

Windows 9X BSOD

The old version of the Blue Screen Of Death.


See also: Worm

A worm is a piece of malware that will spread through multiple services, usually harvesting domains and legitimate contacts to spread itself.

Email Worm

See also: Email Worm

Email Worms are self-explanatory, they are worms that spread through email services. These usually consist of innocent looking emails, telling you to try out a game or advertising an update for a piece of software. When run, it will execute its payload and repeat the process to another user.
Malware statics 2011-03-16-en.svg

Malware statistics from 2011

IRC Worm

See also: IRC Worm

IRC worms are also kind of self-explanatory, they are a sub-category of worms that spread through IRC channels. They are similar to Email Worms as to they provide innocent looking messages with malicious attachments.

Internet Worm

See also: Internet Worm

An Internet worm is a worm that spreads through Internet connections, sometimes infecting popular domains. Some Internet worms can be javascripts in the website. An example is "You Are An Idiot" and "Hurr-Durr". These types of malware is common nowadays.

Network Worm

See also: Network Worm

A Network worm is a worm that spreads through workgroups, homegroups etc. Infected machines may distribute the malware to other users on the Network.


See also: Virus

Unlike worms, viruses do not spread. The user may download the file mistaking it for another program from a domain or an email. It will then infect the machine and execute the payload. Some are more lethal than others.

See also: Trojan

Unlike other pieces of malware, trojans do not always have bad intentions. Trojans are programs that appear to be legitimate, but either have a major security flaw or are intentionally malicious. Not to be confused with adware. These types of malware is not that common nowadays.


Ransomware is incredibly dangerous. As you can see or infer from the name, ransomware will do things such as encrypting files, and will force you to pay money through online payment transactions for a decryption key, however this is not a good move as it could possibly be a "troll" or bait to fool you into giving away credit card info, and it also encourages the cyber-criminals to continue to do this. Examples of ransomware is the Cryptolocker virus and the Locky virus. This type of malware is very common nowadays.


See also: Adware

Adware is certainly one of the most common types of malware these days. As you can guess from the name, these are generally downloaded through ads. They are also distributed through download helpers and sponsored downloaders, such as 4shared, CNET and Softonic. There are also many sub-categories of this type of M\malware. Basically, they simply add more advertisements to about any webpage you go, and try to redirect you to more malware. They commonly come from toolbars. You can use software like AdBlock to stop the ads from appearing in the first place, though it does not get rid of it all.

Fake Software (Rogue Software)

Rogue software is phony software that uses malware and other exploits to get inside your computer. There are many types of fake software, ranging from antiviruses to disk optimizers. After downloading, they often perform a scan, find a load of fake objects and offer a price for an activation key. If the user pays this, they will be simply laughed at, as the program deletes itself [and the user would have paid at least $50], or the ones who made the program will commit identity theft. This type of malware is very common nowadays.

Browser Hijackers

Browser Hijackers are another common piece of adware, often these will install with Sponsored Downloads. They exploit the fact that very few people properly read installers, and often allow programs to set themselves as your homepage, default browser and default search. The simplest way to get rid of these is to run AdwCleaner and reset your browser to its default state. This type of malware is very common nowadays.


Sometimes bundled with Browser Hijackers, these often add toolbars to your browser's taskbar. Not only are these annoying, they are often intrusive to the user's experience. They cannot be removed easily without Anti-Junkware tools. However, not all toolbars are malicious.

OEM Bloatware

This is found when you buy a new computer that's cluttered with malware to begin with. These can range from any piece of adware or other malware, often "potentially unwanted applications".

Some manufacturers disgustingly bundle Browser Hijackers such as MyWebSearch with their computers, and charge for removal. The best way to solve OEM bloatware is to either run an anti-junkware tool or format. However, some pieces of bloatware are actually legitimate applications, that probably won't be detected. This type of malware is not that common, and are only usually found when bought from less popular locations.


Spyware is self-explanatory. It can spy on you and steal information. You might find it in some PUPs or trojans such as BonziBUDDY. This type of malware is common nowadays.

Joke Programs

Main article: Joke Program

Joke programs are not too deadly to destroy a computer, but can still be an annoyance. An example is Joke:VBS/CDEject.D and Button, a joke program. Only a few are deadly, which includes WinFastener (which deletes a startup file to prevent the computer from booting) and Lose/Lose (which deletes personal files, and if it goes long enough, system files). This type of malware is uncommon nowadays.


Main article: Hacker

Hackers aren't exactly considered malware, but are just as dangerous (if they have bad intentions) as some kinds of malware, as they can insert viruses into your computer, damage it via command prompt, or ddos you. They can also spam you with other things, or completely corrupt your computer. Hackers also can crack passwords in emails, games, bank accounts, and other things.

There are three types of hackers, White Hat, Grey Hat and Black Hat.

White Hat Hackers tend to hack into a website or emails to test security. However, Grey Hat Hackers can do this too.

Grey Hat Hackers are a combo of White Hat Hackers and Black Hat Hackers. They may help or do damage for fun. They can and sometimes will do both for fun and/or money.

Black Hat Hackers are hackers with bad intentions. Some are responsible for viruses, worms and trojans. Examples are: Botnets, Sobig, Melissa and many more like Cryptolocker. These Hackers work for destructive or money-based purposes hoping to destroy and/or scam as many people as possible. These Hackers are notorious in the world for the damage they seek to cause. Some of these hackers would have people pay them to hack people or companies.

This type of issue is quite common nowadays.


Similar to hackers, these are not really malware, but these can also glitch and damage software. This type of issue is usually seen on nearly every program.


Definition of Malware according to Microsoft

Malware on Wikipedia

Computer virus on Wikipedia

External links