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What is malware?

Here’s everything you need to know about what malware is and how to prevent it.

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Everything you need to know about what is a malware_alt
Malicious software equals malware definition_alt

Malware definition

The definition of malware comes from combining two words: malicious + software = malware. Malware is software designed to work against the interests of the owner of a system or device. Some types can find their own way into your device, while others need to be planted there.

What does malware do? Its effects vary in severity, from tracking relatively harmless data to holding your device at ransom or destroying it for fun.

Types of malware and malware attacks

You’ll find malware types of every sort below. There are countless varieties out there, so we’ll stick to some of the most widespread malware examples. Here are the top most common types of malware:

Adware is a type of malicious software that focuses on making money_alt


Adware is a relatively innocuous type of malicious software that focuses on making money rather than harming your computer. This aggressive advertising-supported software displays banner advertisements on websites and application windows.

Symptoms may vary, but the main one will be pop-up ads. They may show up on your desktop or in programs, websites, or apps that didn’t have them before.

Spyware is spying on the man using computer_alt


Spyware is made to (surprise!) spy on you. This malware hides in the background, monitoring your computer usage and internet browsing activity. It can harvest passwords, banking details, and emails and even perform keystroke logging or change security settings. All of the information it gathers is sent to a remote user. It can also download and install other malicious applications without your permission.

Virus infects computer and other devices_alt


Much like a biological virus, a computer virus will spread from host to host to infect as many devices as possible. Attached to files or programs, it can be spread through downloads, email, social media, or text messages.

However, a virus usually cannot infect a computer autonomously – it needs a user to run the program it is attached to. The harm caused by viruses ranges from minor annoyances like desktop wallpaper alterations to major system crashes or complete loss of data.

Worms extracting information_alt


In comparison to viruses, worms can seem quite innocent, as they do not cause any direct damage to a system. A worm’s entire purpose is to copy itself and spread across a local drive or network.

Worms can also be paired with “payloads” designed to damage a system or extract information, but they don’t have to. The first worm, Creeper, simply notified infected users of its presence.

Trojan malware infiltrates woman’s computer and causes damage_alt


Trojan malware infiltrates computers by hiding in innocent-looking programs, like the Trojan horse of the Greek legend. Once it’s in, it can create backdoors for hackers to get into your system and collect your data or even completely lock you out of your computer. For example, the Zeus trojan collects data like victims’ keystrokes and credentials. Emotet was notorious for stealing data from individuals and companies alike.

Ransomware is cyber threat that spreads quickly and causes costly damage_alt


Ransomware is one of the most serious cyber threats due to its ability to spread quickly and cause costly damage. Ransomware is designed to make a profit. Once the malware infects a machine through a system vulnerability, it encrypts all data, locking the user out. Then, it asks the victim to pay a ransom to decrypt the files.

Keylogger tracking its victim_alt


Keylogging is the process of tracking the keys a user types to discover their sensitive passwords or monitor private communications. Different types of keyloggers exist, including ones based on stalkerware or hardware. This can make them very hard to discover as well.

How malware spreads

Malware could infect your devices in several different ways. Here are a few of the most common ones:


The most popular method of spreading viruses is through email. Both simple spam and sophisticated phishing attacks still trick people into clicking on links or downloading attachments that contain malware.

Careless browsing

If you click on any pop-up or advert that you come across while browsing, chances are, you’ll eventually end up on a malicious website. It will download malware in the background, and just like that, you’ll have a keylogger or a trojan on your device.


Some malware spreads from one device to another through the internal network. For example, someone in the office forgot their cybersecurity training and clicked on a malicious link. So the next day, everyone’s computers are infected, and all their files are encrypted, with no access to their accounts.

Bundled software

Malware is known for piggybacking. So even when you download a trustworthy piece of software, you might end up with more than you asked for. You can install malware together with legitimate software without even noticing, and it could be anything from slightly annoying adware to spyware stealing your banking data.

Signs of malware

Changes in speed

Your device or browsers have slowed to a crawl

Performance issues

Your device frequently freezes or crashes

Apps acting weird

Programs on your computer open or close without warning

Suspicious apps

Files, add-ons, or apps on your device that you don’t recognize

Setting changes

Your security, browser, or app settings change without your consent

Unusual messages

Unusual emails or texts that were sent without your permission


Your device overheats, or its battery drains super fast

Suspicious charges

Your phone bill has increased without you knowing why

How to prevent malware?

Here’s how you prevent a malware attack:

Woman using ultimate antimalware security software_alt

Use antimalware security software

One of the most comprehensive defenses against any malicious code is a piece of reputable security software. As always, premium tools are the way to go. The best software packages are backed by dedicated teams of developers who monitor the latest threats and respond to them with updates as quickly as possible.

Staying safe by being aware of malware threats_alt

Become a vigilant Internet user

Don’t ever click on pop-ups, and make sure you’re clicking on the right “X” to close them. To make things easier, switch on NordVPN’s Threat Protection feature, and it will block ads for you. Mouse-over or right-click on links before clicking on them to see where they take you.

Back up files for extra protection_alt

Back up your files

Maintaining frequent backups of your files may not prevent you from getting malware, but it will make attacks much easier and less damaging to deal with. Device resets are a nearly guaranteed way to wipe out most malware, but they’re very hard to do if every wipe means losing important files. With frequent, secure backups, that won’t be a problem.

Research and read reviews to avoid possible malware threats_alt

Do your homework

Before downloading an app, read some reviews online – and be sure to find at least one negative one as well. What do they say? Are users complaining about features or performance, or are there more serious issues at play? Has anyone accused the app of being malware?

Research the most serious vulnerabilities facing your device or operating system. If you know them, you can avoid them.

A man updating his software_alt

Keep your software up to date

When a trusted app or your OS asks you to confirm an update, you probably should. In addition to providing feature and performance improvements, updates usually patch up newly discovered security vulnerabilities.

Protecting devices with strong passwords_alt

Change your passwords and keep them secure

Learn how to craft a strong password that you’ll remember. You can also use a password manager like NordPass so that you don’t need to rely on weak passwords – it’ll generate, remember them and secure them for you.

When you discover malware on your device and eliminate it, one of the first things you’ll want to do is change your passwords.

Using NordVPN to stay extra safe_alt

Learn your devices inside and out

Whether it’s a smartphone or a PC, your device has plenty of built-in settings that can go a long way to make it more secure.

You can use the NordVPN app on smartphones, laptops, PCs, and routers, enjoying better protection from malware across all your devices, especially with the Threat Protection feature.

Protect your digital life with more cybersecurity apps

Enjoy the all-round security provided by our apps. Protect your internet traffic, passwords, and files.

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NordPass password manager

Let NordPass be your everyday companion. It will keep your passwords close at hand even when you’re offline, making your digital life safer and simpler.

Data Breach Scanner

Get alerted before damage is done. A built-in NordPass Premium feature will scan the web and inform you if your sensitive information has been exposed in a data breach.

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Easy-to-use encrypted cloud storage

NordLocker will keep your files backed up, synced, and protected from snoopers, loss, or malware in its secure cloud. Nobody will see, touch, or sell them.

No app needed with Web Access

Don’t want to download more apps? NordLocker’s Web Access will let you securely access your end-to-end encrypted cloud lockers via a web browser.

How does NordVPN help?

How NordVPN can help depends on the malware you’re up against.

Blocks dangerous websites

NordVPN’s built-in Threat Protection feature blocks access to malicious websites before they have a chance to trick you into infecting your device.

Deletes malicious files

Threat Protection scans the files you download and, if malware is detected, instantly deletes it.

Fends off pop-ups

Threat Protection blocks potentially malicious ads before you even get the chance to see them.

Secures traffic

The encryption a VPN provides will close off numerous avenues of infiltration for potential hackers and their malware (but not all of them).

Enjoy robust cybersecurity with NordVPN

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