Malware has been a big interest of mine since I was younger! When I was a kid on the internet, I often downloaded programs which included a lot of adware, spyware, and sometimes actual computer viruses! This lead to me developing a big fear of them, as well as a bizarre interest in them. In my earlier teens, I used to code relatively inefficient malware on older computers where it was safe and I couldn't actually cause any real damage. It was super fun! While I have no use for these skills anymore, I still find older malware very interesting. Obviously, I do not endorse malware, nor think it's a good thing. I simply find it intriguing!

Malware has essentially existed since the dawn of computing. The title for first computer virus is often attributed to Creeper, a program which displayed a small, harmless message to a user, then spread to the next computer. Creeper did not actually cause any damage to the computers it infected, only being created in the first place as an experiment, though another program called Reaper was subsequently released to destroy it. Since then, different types of malware quickly began being created and propagated. The Morris Worm is a particularly infamous computer worm which became one of the oldest malware to spread through the internet. The source code for the worm is actually still stored today, in a floppy disk at the Computer History Museum in Mountain View, California. Over time, these viruses became more and more complex and dangerous. Certain malware, such as MyDoom, ILOVEYOU, and Happy99, gained mass media attention and are still well-known in media today. The golden age of computer viruses rested in the 80s and 90s, which was a peak time of virus development and spread. As Y2K rolled around, users became more educated on cybersecurity, and malware became more cryptic in order to adapt. This remains today, with adware and spyware being the most common forms of malware we still see.

Malware exists in many different forms. Some more common forms include...

Adware are a type of software which display unwanted advertisements on a user's computer. Typically these ads are shown in the form of pop-ups, which are often unclosable and injected into webpages. Adware is often one of the least dangerous types of malware, some forms not even being considered malware and rather called "grayware". They typically only exist for the profit of the adware's developer. BonziBuddy is a well-known piece of adware, and is well-known in internet culture.
Backdoors are programs that allow someone to slip by security systems pre-installed within a computer and gain access to the system. Backdoors can be used to spy on a user, but are often used by other types of malware in order to inject themselves into a computer without being detected. Backdoors can be used directly by another person to access important passwords and files, and completely destroy files that may not have a proper backup.
Ransomware is a type of malware that encrypts a user's files, and often locks down their PC, whilst demanding payment from the user to recover their files. (Therefore holding the files for "ransom") Ransomware sometimes does not allow a user to recover their files, even if the sum is paid. A very recent example of ransomware is the WannaCry program, which was an incredibly prolific piece of ransomware which had a massive outbreak in May of 2017. It affected 300,000 computers across 150 countries.
Rootkits are groups of software that aid malware in remaining concealed. They often allow programs to enable access to parts of a PC they may not have been able to before, such as parts that are only available to authorized users. They are most often very difficult to detect, due to their design.
Spyware are programs that monitor a user's activity. This can be used for the purpose of stealing sensitive information, such as identity information and bank accounts, or to show undesired advertising. Spyware is typically associated with adware.
Trojans, also called Trojan horses, are a kind of malware that deceives a user by presenting itself as something harmless, or even helpful, to bait a user into installing it. Trojan horses often disguise themselves as anti-malware programs or harmless emails.
The term "computer virus" is often used to refer to all types of malware, though not all kinds of malware actually are viruses. Computer viruses are programs that repeatedly copy themselves into other files, as well as other computers, with the intention of causing some kind of harm to the computer. Due to it's ability to conceal itself within other programs, it can spread very rapidly.
Computer worms are a variety of malware which, like a virus, replicates itself rapidly. Worms travel to other computers by a variety of means, often using computer networks or even emails. Computer worms often spread very quickly, and are not always intended to cause harm to a host computer. Regardless, they can still overwhelm and disrupt important networks. The ILOVEYOU worm is one of the most virulent computer worms in history and is incredibly well-known in pop culture. It affected over ten million Windows computers in May of 2000.

Of course, not all types of malware are covered here! These are just some more notable ones in my opinion.

My favourite piece of computer malware is known as Kuku. It is an Eastern-European virus created to infect MS-DOS. It injects itself within .COM files. Upon a file infected by Kuku being run, it displays several colourful, sometimes flashing boxes with the text "Kuku!". It also disables all keyboard inputs, aside from CTRL+ALT+DEL. The payload will continue progressing until it fills the entire screen. It's my personal favourite due to the spread method, as well as the rather interesting payload.

Below is a demonstration of Kuku, made by the wonderful danooct1. His channel contains a lot of other demonstrations of older (and some newer) malware, I highly reccomend you check him out!

It's always good to remain vigilant of computer malware. Don't click suspicious links or download suspicious files, and remember that you are always susceptible!

Also, a small pet peeve of mine I'd like to note at the very end of this page... YouAreAnIdiot is not dangerous malware! It was a very popular website often misconstrued as a computer virus. In reality, YouAreAnIdiot was a simple JavaScript trick that did not harm the computer, and could easily be stopped by a simple reset, or by closing the script in task manager. I still do not recommend messing around with the modern equivalents of it, but the idea that it is some highly sophisticated malware has always bothered me.