What is malware?
Through malware attacks, cybercriminals can do great damage to your computer and gain access to personal information, health records, passwords, and other information that you can risk being either deleted or misused.
Definition and history of Malware
Malware definition
Malware, short for malicious software, refers to any type of software designed to harm or exploit a computer system. This harmful software can take many forms, including viruses, worms, trojans, spyware, adware, ransomware, and more. Each type of malware has its own unique way of causing trouble, from slowing down your computer’s performance to stealing sensitive information or even taking control of the entire system. Essentially, if a piece of software is created with the intent to cause damage or unauthorized access, it falls under the umbrella of malware.
History of malware
The history of malware dates back to the 1970s, when the first computer viruses were discovered. These early viruses were relatively harmless, often created as experiments or pranks. However, as technology advanced, so did the sophistication and maliciousness of malware. The 1980s saw the emergence of the first worms and trojans, which were more disruptive and harder to detect. The 1990s brought a surge in spyware and adware, as the internet became more widely used. In recent years, ransomware has become a major threat, with high-profile attacks like WannaCry and NotPetya causing widespread damage and highlighting the need for robust cybersecurity measures.
Malicious software is a threat to your IT security
The word malware is a contraction of the English words “malicious software” and is a collective term for a variety of malicious software that can infect computers and their programs and perform harmful actions.
Employing multiple security layers is crucial to detect malware that infiltrates systems, ensuring that threats are identified and mitigated promptly.
There are different purposes of malware, which may include:
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Exploiting personal information
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Monitor online behaviour (spyware)
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Delete data
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Perform ransomware attacks
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Send unwanted advertisements (adware)
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Carry out DDoS attacks
How to install malware?
You can be affected by malware in many ways. Most often, malware is installed on a computer device through phishing. In phishing, cyber criminals lure their victims to click on a link or download malicious files in an email. In both cases, malware can be installed on the victim’s computing device.
It can also happen through security holes in legitimate computer applications on one’s computer, such as Windows, Java or Adobe.
Cyber criminals can also infect official company or organisation websites with malware code that activates fake pop-up messages when someone visits the website. In some cases, cyber criminals create their own malicious websites that can spread malware if someone accesses the site.
How malware spreads
Malware can spread through a variety of means, making it a pervasive threat to computer systems. Understanding these methods can help you better protect your devices.
Ways malware can infect computer systems
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Phishing attacks: One of the most common methods, phishing attacks involve cybercriminals sending emails or messages that trick users into downloading malicious attachments or clicking on links to infected websites. These attacks often appear to come from trusted sources, making them particularly dangerous.
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Infected software downloads: Malware can be embedded in pirated or cracked software, or even in software downloaded from untrusted sources. Always ensure you download software from reputable sites to avoid this risk.
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Infected websites: Simply visiting a compromised website can result in the download of malicious code onto your computer. These sites often exploit vulnerabilities in your browser or plugins to deliver malware.
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Infected USB drives: Inserting an infected USB drive into your computer can spread malware. Always be cautious when using USB drives from unknown sources.
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Network vulnerabilities: Malware can exploit vulnerabilities in network security to spread from one computer to another. Ensuring your network is secure can help prevent this type of infection.
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Legitimate software vulnerabilities: Even legitimate software can have vulnerabilities that malware can exploit to gain access to your computer system. Keeping your software up to date with the latest security patches is crucial.
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Social engineering: Cybercriminals often use social engineering tactics to trick users into installing malicious software or revealing sensitive information. This can include fake tech support calls, deceptive pop-ups, or fraudulent messages on social media.
To protect against these threats, it’s essential to have robust security software and practices in place. This includes keeping your operating systems and software up to date, using reliable antivirus software, and being cautious when downloading software or clicking on links. By staying vigilant, you can significantly reduce the risk of a malware infection.
How can I detect malware on my computer?
Malware can be difficult to detect, but there are a few things you should consider if you suspect an infected computer:
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Is your computer very slow all of a sudden?
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Does your webcam turn itself on?
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Do new windows open by themselves?
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Are you having trouble getting online?
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Is your browser sending you to the wrong places?
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Do you suddenly have programs on your computer that you didn’t install yourself?
Types of malware
There are many types of malware that can harm your computer.
Trojans. Trojans are a type of malware that masquerades as legitimate programs, files or updates in various ways. They may look like an email attachment from a colleague or a security update. When you download the file or application, your computer becomes infected with the Trojan horse. Explore the dangers of Trojan malware and how it fits into the broader category of cybersecurity threats in our blog post.
A computer worm. A computer worm is a computer program that, once a computer is infected, copies itself and spreads over the network or Internet connection and can infect any unprotected computer and server on the network.
Virus. A computer virus, like worms, is a computer program, but a virus infects an existing program, a “host program”, on a computer and then copies itself and spreads to one or more programs or computers on a network.
It has become easy to identify a virus with anti-virus software, so computer criminals don’t use computer viruses very often anymore.
Spyware. Spyware is used to monitor and collect personal information from your computer. Spyware can monitor your operating system, email and your behaviour on the Internet, such as the websites you visit. This monitoring is used, among other things, to see your passwords when you enter them.
Ransomware. Ransomware is a type of malware that locks your computer or other devices and prevents you from accessing your data, in part by encrypting the data. You will then be asked to pay a ransom in cryptocurrency to regain access to the data. Cybercriminals continue to refine their tactics, making ransomware attacks more frequent and damaging. Learn more about how ransomware works and how to protect yourself from these threats.
Mobile malware is another significant threat, particularly to smartphones that store sensitive personal information. Due to the larger market share of Android devices, they are often targeted by various types of mobile malware.
Protect yourself from malware with antivirus software
To avoid malware, you can protect yourself in several ways, both in terms of precautions and technical tools.
Use an antivirus program
An antivirus program is a program that scans your computer and selected applications to find and remove malware, especially viruses. It is important to regularly scan your device and all relevant applications. In addition, remember to update the antivirus software itself. Some spyware can grant remote access to malicious users, allowing them to collect sensitive information without your knowledge.
Take regular backups of your data
If you are hit by a malware attack, the hacker may lock or delete your data. So back up your photos, documents and other important data regularly. That way you can be sure your data won’t be lost. It can be a good idea to back up both to an external physical hard drive and to a cloud-based solution, such as Dropbox or Google Drive.
Make sure you don’t always automatically log in to your backup or have the external hard drive connected to your computer.
Update your computer regularly
You should update programs and systems regularly to protect your computer from malware. Many types of malware and other digital threats exploit security holes in your computer’s softwaree, so you reduce the risk of malware if your applications always have the latest security patches. You can set your computer to update automatically.
Make sure you have a firewall
A firewall is a protection between your computer and the open internet. Your firewall controls what data and files are sent in and out of your computer. The firewall can protect your devices from malicious software or files from the internet. Want to understand how firewalls work and why they are essential for cybersecurity? Dive into our guide on firewalls and network security.
Do not click on pop-up messages
You may receive pop-up messages in your browser when you are online. Typically they will say that your computer is infected with a malicious program, that you should scan it immediately to avoid viruses, or that you should download some tools to protect it. Don’t click on them or try to close them as they contain malware themselves.
Watch your emails
Be aware of emails you don’t expect to receive or where you don’t know the sender. Do not click on links or download attachments in emails sent to you unsolicited. If in doubt, contact the sender.
You should also be aware of unsolicited messages on online networks or social media, such as Facebook. Hackers also try to get victims to install malware through chat messages or comment tracks.
What can I do to remove malware if I have been hit?
Most malware is difficult to remove yourself if your computer has been infected, so removing malware promptly is crucial to mitigate potential damage. It is a good idea to contact some professional computer or security experts for help.
If your computer is infected with malware and you are able to turn it on, you should disconnect it from the Internet. You should also delete temporary files, clear cache and cookies from your browser and scan your computer with an antivirus program to identify and quarantine threats, ensuring complete removal to prevent reinfection.
It’s a good idea to change your passwords regularly, especially once your computer has been infected with malware.
Learn about rootkits that put hackers in control in our blog post, and how they differ from other forms of malware.
This post has been updated on 05-02-2025 by Sarah Krarup.

Sarah Krarup
Sarah studies innovation and entrepreneurship with a deep interest in IT and how cybersecurity impacts businesses and individuals. She has extensive experience in copywriting and is dedicated to making cybersecurity information accessible and engaging for everyone.
View all posts by Sarah Krarup