Different types of computer malware, and the way they infect computer

Both good and bad exist in this universe, and the mere world of computers isn’t an exception to that as well. When you can find thousands of programs or software packages to be more productive, and help you with everyday tasks on your computer and smartphone, there are even some bad guys who always try to do the opposite. We all know about such programs or software, and they are called malware, which is an acronym of malicious software. Unless you are living under a rock, you have already heard this term. Besides that, we all know about computer viruses which are specific programs that are designed to affect our computers in some way or the other. I have seen people getting confused between the terms of malware and computer viruses.

But malware is the domain of computer program, which has the sole intention of impacting our computers in negative ways. Depending upon the malicious behaviour each malware display, they are grouped into different categories, and the most common among them are Viruses, Worms, Trojans, Ransomware, Adware, etc. All types of malware infect our computer, steal data or do any other malicious thing that eventually causes problems for the end-users. So if you are a computer enthusiast, it is worth knowing the difference between different kinds of malware so that you can take the appropriate steps to stop your computer from malware attacks in your future either by being more careful or by using some specialized software to keep the bad guys, a few hands away from your computer.

different types of computer malware

So, without any further delay, let’s get started with how each of them is harmful to your computer.

What are the different types of computer malware?


We all have heard or read about biological viruses, which makes us sick. The same goes for computer viruses which does pretty much the same thing with a computer by corrupting software and your files. That’s why computer virus is an abbreviation of Vital Information and Resources Under Seige. In most cases, computer viruses come in the form of executable or normal files, which can be opened by an executable. Once you open it, the malicious code will be executed, which will subsequently cause serious troubles depending upon the severity of the virus. Once the code is executed, it might also affect other programs on your computer and everything will typically happen behind the scenes, without making you aware of anything that is going on. 

Some viruses that come with an executable file might keep affecting other programs and personal files. Each time you share the file with somebody, and they open the same, the malicious code will be executed on their computers as well. Computer viruses can corrupt your files and in the worst case, they can even cause Distributed Denial of Service (DDoS). However, viruses cannot propagate on their own from one computer to the other and it usually takes place due to human errors and carelessness. The process of infection initiates only after it is executed either by a computer user or through autorun files, and automation scripts.


Worms also work in almost the same way as viruses do, but are different altogether. Unlike viruses, worms do not come as an executable file or any other user file, however, it gets access to a computer system by exploiting the vulnerabilities of the system or the network it is connected to. Unlike viruses, worms can replicate themselves, and get transmitted to other computer systems to do the same work of replicating on those systems, as well. Besides exploiting the vulnerabilities of a system, worms can also get access to a system by tricking a user to open some links or by using social engineering tricks.

As the worms keep multiplying themselves to attack multiple targets, it eventually uses a lot of system resources and you can find a drastic effect on your computer performance if your system is infected by some kind of computer worm. Unlike viruses, worms can be remotely controlled, which can be used by hackers to know the state of a computer system and impose additional payloads to infect the target. As worms replicate and transmit on their own without any human intervention, it is really tricky to stop worms from infecting computer systems.


Unlike viruses and worms, Trojans aka. Trojan Horses look like legitimate applications and most users are tricked to download and install them for the useful purposes it is advertised with. But once a Trojan gets access to a computer system, it can do all kinds of malicious activities which includes, stealing user data, corrupting files on a computer system and in the worst case, it will also open a door to hackers so that they can have access to an infected system.

However, unlike worms, Trojans cannot multiply themselves and they need to be downloaded by the end-user and that should be opened or executed, just like a virus, so that a Trojan can do its job. As the Trojans come masked as useful applications, it is a real trick to find them out and the fact that they can steal user information is the reason, Trojans are considered to be the worst kind of malware in the current days.

So, those were the three basic kinds of malware which we all need to know. But besides these three categories of malware, there are even some other Malware categories which target a user in a specific way, and I will discuss them one by one in short here.


I am sure everybody has come across adware if they spend most of the time on the internet. Adware is a special kind of malware which collects advertising data, and data about your likes and dislikes without your consent. Adware comes packed with browser toolbars, and some third-party addons by not so popular developers that most people install on the browser.

Once a computer is infected by adware, the searches made by the target might be sent to a different server or he might even see unnecessary advertisements instantly for the searches made. Sometimes, the victim can also see pop up advertisements, no matter what the user is working with. Adware thus collects your private information which can be used for targeted advertisements and also show you unnecessary ads from time to time in a disruptive manner.


Just like adware, the term spyware can also be self-explanatory, and what it does is simple. Spyware will spy on you without your consent, and besides sending data to its own servers for showing targetted advertisements, spyware can also steal your bank account details, an email account password, your browsing history and pretty much everything else that defines a spying behaviour.

Spyware works in the same way as adware, but the ability to sneak into the browsing habits and other sensitive information makes it one of the biggest threats in today’s world of technology. Just like adware, spyware also comes packed in browser toolbars and addons from not so popular developers. Sometimes, a few computer programs can also come with spyware from time to time. Spyware act almost the same way like Trojans, however, its work is, in most cases limited to sending your private details to its own server or any other third party source depending upon the specific spyware.


A few years ago WannaCry ransomware took the internet by storm. What it did was, it locked down the personal files of the infected computer systems and the respective users or victims had to pay a certain amount of money before they can get back the access to the files. That’s how ransomware fundamentally works. It will lock down your computer or the files on it, typically by some form of encryption, and the only way to get them back if by paying the ransom.

The main cause of attackers to spread ransomware programs is basically for monetary gains, and they demand money in the form of some cryptocurrency like Bitcoin. Just like adware and spyware, ransomware cannot travel or propagate on its own, however, it requires the intervention of the computer used to run some infected program on the computer for the ransomware to start its work. After a system is infected by any ransomware, it will typically show a message to the user saying, the user will have to pay some money in order to unlock the computer.


Bots, the abbreviation of robots can be used for automating a number of tasks on a computer, from replying to instant messaging applications, carry out some repetitive tasks automatically at a certain point of time, handle phone calls and for a number of other useful purposes. However, depending upon the bad intentions, a developer might have, bots can also be used for malicious activities. Bots, in most cases, can propagate just like worms however they are more powerful compared to them. Bots can even create a backdoor for hackers to get access to a system and they can even carry out certain activities by getting commands from a central server.

In most cases, multiple computers are infected with a common type of bot to create a botnet which can later be used to launch Distributed Denial of Service or DDoS attacks to freeze a server or stop a website or server from stop responding at all. Besides that, bots can also be used to carry out some malicious actions on the infected computer, from logging keystrokes to steal financial data, and cause a number of other losses to the user of the infected computer. Bots are really threatening to a computer system, as it acts like worms, and they might even go unnoticed by antivirus and antimalware programs.


The final kind of malware that is quite common is Rootkits which acts in a different way compared to that of other malware programs that I have mentioned above. A rootkit needs to be installed on a computer system which is hardly possible without human intervention, and once installed, it gets access to the lower levels of a computer system, typically the kernel and to even lower levels, like the BIOS, That said, it can cause serious damage to the operating system or can even change the system configuration that might stop you from carrying out some specific tasks on your computer.

A rootkit can even change or overwrite the operating system files, which in the worst case can cause the operating system to stop functioning at all. Once a computer is infected by some kind of rootkit, it can be controlled remotely by the attacker to cause different kinds of harm to the computer system. As rootkit resides mostly in the kernel level or binds with system files, they’re really difficult to detect by any antivirus or antimalware programs.

Most experts will recommend users to carry out a complete format of their hard drive or solid-state drive whichever is applicable, install the operating system and other elements from scratch to get rid of a rootkit.

So, those were the different kinds of malware, which you will find. As computers and mobile devices are getting smarter day by day, malware has also developed themselves with time, and there can be even some powerful malware, that might seem to be a virus, but can end up behaving like a Trojan, or do some serious harm to your system. 

Malware is categorized depending upon their behaviour, and cybercriminals are always trying their best to create new varieties of malware to infect computer systems in whole new ways. The category of malware programs, which I have discussed here are commonly found today, however, in the future, we might find more advanced Malware programs, which might be completely different from and even act in a smarter way compared to that of those I have discussed here.

Talking about ways to get rid of malware, I would rather say, prevention is better than cure. Stay away from pirated contents, and files from sources that you don’t trust. Besides that, if you get an email from some unknown person, don’t download or open any attachments, or click any link as it might start its initial stage of infection depending upon the type of malware it might be. Besides that, make sure that the antivirus definitions are updated from time to time and you have a strong firewall on your computer. I will talk about different ways you can keep yourself and your computer safe from malware in the coming days.

That’s all that you should know about computer malware. Do you know any other type of malware? feel free to comment on the same below.