Understanding Malware and Other Malicious Software

Malware is short for “malicious software.” It is a broad term that refers to any software, program, or code that is designed to infect and damage a computer—and it includes viruses. There are a lot of different types of malware, and they all inflict harm in multiple ways. It helps to understand what kinds of malware are out there and how you can defend yourself against them.

This type of malware is also referred to as scareware. It can lock down certain files or your entire computer and hold them hostage.

Ransomware works in two ways—it either encrypts your files and threatens to delete them or locks you out of your computer completely. The perpetrators of ransomware attacks threaten to destroy everything unless a users pay a ransom.¹ Most of the time, ransomware targets large organizations because they have the most to lose and the most resources available to pay.

In light of continued ransomware attacks, computer security companies have developed anti-ransomware that that can either prevent an attack or release a computer from the ransomware without any money changing hands. You can get a tool dedicated to rooting out and destroying ransomware threats or find an antivirus program that includes anti-ransomware in its features.

This is malicious software designed to spy on you. It runs in the background and captures your online activity. It can grab passwords, bank information, credit card numbers, and your browsing history.

Anti-spyware is designed to identify and remove spyware programs. Anti-spyware programs use rules-based methods and definition files to detect known spyware programs.

Fortunately, if spyware has already infected your computer, you can find it and get rid of it with an anti-spyware program. Anti-spyware can be added as a stand-alone defense or included as part of a comprehensive antivirus package.

A computer worm is a type of malware created to make a device inoperable. Worms can self-replicate to clog up the device's resources. Worms hide in parts of the operating system that are automatic and hard for a user to detect. You typically won’t notice a worm until its out-of-control replication starts using up enough computer resources to slow down or disrupt computer function.

One of the best ways to keep your computer worm-free is to keep your operating systems and software updated with the latest security patches. Firewalls and antivirus software are other effective defenses against a computer worm. And don’t click on links or open files from unknown sources.

Named after the famous horse, Trojan malware either hides within or disguises itself as legitimate software. It’s a sneaky form of malware that creates holes and backdoors in your security so other malware can get in.

The good news is that Trojans need permission to run on your machine, so the best defense is to stay away from links and attachments from sources you don’t recognize. Keeping software and operating systems updated and using antivirus software will also help keep the doors locked against a Trojan virus.

Learn more about how to tell if a website is safe.

This sort of malware isn’t always malicious, but it can still cause damage by slowing down your system and bombarding you with pop-ups. Adware isn’t designed to destroy your computer or steal your data—it wants to get you to buy whatever it’s selling.

Getting adware off your computer can be a frustrating process, but it’s worth it. To wipe the slate clean, you want to completely disconnect from the internet, uninstall the programs through the Control Panel, and scan your computer to make sure you got everything. You can also use a spyware removal tool like MalwareBytes (its free version is great, read our Malwarebyte review) to scrub your machine clean.

Some adware can regenerate after you go back online, so be sure to reset your browser settings before logging back on. Another tactic is to install an ad blocker, which may block malicious ads so they never get to you. But be careful to select a legit ad blocker, because there are some fakers out there that could be dangerous.²

A rootkit lets someone other than you access and take control of your computer. And it does it without you knowing that it’s happening. The owner of a rootkit can covertly change system settings, access files, and monitor user activity. There are some legitimate uses for rootkits (usually by law enforcement, parents, or employers), so they’re not always considered malware.

Wiping out rootkits on your computer isn’t as straightforward as detecting and removing other forms of malware. There is no specially designed program that finds and removes rootkits. That means getting rid of rootkits could be as simple as giving your system a good cleaning or as complicated as a complete rebuild.

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• How to Keep Your Smart Home Safe from Hacking
• Internet Safety: How to Avoid Online Scams
• 10 Cybersecurity Tips for Online Shopping

1. David Bisson, Tripwire, "10 of the Most Significant Ransomware Attacks of 2017," December 2017. Accessed March 29, 2022.
2. Aatif Sulleyman, Independent, "Google Chrome Users Tricked into Downloading Fake Ad Blocker." Accessed March 29, 2022.