What is malware?

2020-03-18 - 4 min read

What is malware?

Malware is short for “malicious software.” It is designed to cause damage to systems, networks, and devices or to steal data. Malware can be something as simple as adware showing you annoying ads. But it can also be a virus that destroys your hard drive and infects every device on your network.

There are lots of different types of malware, and it’s incredibly easy to end up with one on your laptop, smartphone, or even IoT devices. Fortunately, there are also many things you can do to avoid it.

What does malware do?

The damage malware can do to a device or system depends on the type of malware that has infected it. Different kinds of malware are identified by how they spread, operate, and the kind of damage they cause.

Trojan. Named after the famous Trojan horse, it acts in the same manner. A trojan will get into a system disguised as legitimate software and will then work as a gateway for other types of malware.

Worm. Worms are similar to trojans in that they are also used to create backdoors for other types of malware to get in. But unlike trojans, worms may have other purposes, like making multiple copies of themselves and overwhelming the network or taking up the whole hard drive.

Spyware. As the name suggests, it is used for spying. Spyware is difficult to detect, as it works silently in the background, collecting information about the user. It may include their browsing history, usernames, passwords, and credit card information that is later sent to the attacker.

Adware. Adware is very annoying, but not necessarily dangerous. It can be used to collect data about the user and sell it to the highest bidder. But its main purpose is to show users ads — lots of them. It may change the homepage on their browser, redirect them to random sites, show pop-ups, install toolbars and plugins without their permission, etc.

Ransomware. Attackers use this type of malware to lock all files on their target’s computer until they pay a ransom. It usually gets in through a phishing email. When you open it and click the link, ransomware downloads and installs on your device. The user usually doesn’t even notice anything until it’s too late.

Botnet. When specific malware infects your device, it becomes a part of a robot network — a botnet. Hackers use botnets to perform large scale cyberattacks, like sending out spam emails or targeting companies and institutions with DDoS attacks. Once a device is infected, it will try to pass the malware on to other devices on the network, thus making the network even larger. Tens or even hundreds of thousands of devices may comprise a single botnet.

Virus. Viruses are one of the most common types of malware. The main difference is that a virus is not a standalone program — it needs to attach itself to legitimate software to operate, much like a biological virus. The damage a virus does to a system or device varies. It can be anything from producing annoying pop-ups to destroying a hard drive or stealing the user’s data.

How to tell if you have malware?

Malware is not universal for all devices and may work and look in different ways on an iPad, a PC, or an Android phone. But some symptoms are the same, so make sure to look out for them:

  1. Your browser is acting weird. If you see loads of pop-up ads whenever you go online, new toolbars and plugins appear on your browser, or you get redirected to random websites, it probably means that your device is infected.

  2. There’s no space on your drive. You might start getting notifications about running out of storage space. This is something that might happen naturally as files and programs pile up. However, if you are sure that there should be loads of free space left, you might want to check for worms. They are known for making multiple copies of themselves and clogging up your drive.

  3. Apps and programs go awry. Some software on your device might start automatically and won’t shut down. It could be a simple bug, but if updates and online research won’t help, it’s better to start taking serious actions. Try deleting the faulty software and then perform a malware scan to make sure your device is clean.

  4. The device is slow and overheats. This is something that can also happen naturally, especially if you’ve had this particular device for a while. But if the change in performance is sudden and the device is heating up even when you’re not using it, it might be a sign that you have malware.

  5. You’re locked out of your device. While some of these signs might seem ambiguous, this one is easy to spot. If you can’t access any of your files, it’s probably because of ransomware, and the attacker will let you know about it. Here’s a detailed guide on what to do in case of a ransomware attack.

How to avoid malware?

Completely removing malware is possible in most cases. Unfortunately, sometimes a full system reset is necessary to make sure that your device is clean. In this case, if you didn’t back up your files, all of them might be lost.

Completely removing malware is possible in most cases. Unfortunately, sometimes a full system reset is necessary to make sure that your device is clean. In this case, if you didn’t back up your files, all of them might be lost.

Therefore, it’s easier to avoid getting malware in the first place than to try to remove it when it’s deep in your system. Here’s what you can do to stay safe:

  1. Keep your software up to date. This means installing all updates as soon as they’re available — not only for your OS, but for your apps, programs, and even browser plugins. From time to time, a dangerous vulnerability pops up, and updates are immediately released to patch them. Your only job is to click “Install” and not “Postpone.”

  2. Be smart about the software on your device. Delete anything you no longer use and always double-check what you download and install. Never use unofficial sources, and even then, see if the developer is trustworthy and read reviews online. Maybe that particular app or program has a vulnerability that is still not fixed? In that case, you should look for alternatives.

  3. Install security software. Antivirus, antimalware, firewall, VPN — whatever you need to stay safe online. This is especially important if you have family members who use the same computer. You never know what flashy ad they might be tempted to click on.

  4. Back everything up. Keep your files in the cloud or schedule regular back-ups. Make sure to save the activation keys to any software you’ve bought, so you can recover your accounts in case something happens to your device.

  5. Stay safe online. Malware ends up on a device mostly when you click on malicious links or download fake software. Therefore:

  • Always check a link in an email before clicking on it, even if it seems genuine.

  • When you visit a website, see if there’s an “https” in the URL and a padlock icon next to it.

  • Only use a secure connection — don’t connect to public open Wi-Fi.

  • Make sure your passwords are strong and uncrackable. They should be long, complex, and unique. These are difficult to remember, so use a password manager like NordPass to store them in a cloud safely. This, combined with 2FA, will ensure that your online accounts stay safe even if your device is compromised.

Benjamin Scott
Benjamin Scott
Verified author
Ben is our tech geek. He analyses difficult topics and brings them to the reader in a nice and simple language. In his free time, he loves to compete, so he likes to participate in various marathons and triathlons.
Subscribe to NordPass news