Virus, Malware, or Worm? What’s the difference?

030414-virusmalwareetcWhen we talk about computer security and the malicious software that can infect your devices, a lot of terms are tossed around. Talking about viruses vs. spyware vs. worms can get confusing – what’s the difference? Here’s a quick primer on the different kinds of dangerous programs out there and some quick tips for protecting yourself.


Malware is short for “malicious software,” and is a generic term for the various kinds of dangerous bits of software or code that can infect a computer. This includes computer viruses, spyware, Trojans, worms and ransomware, all of which we’ll define here.

Computer Virus

Like a virus that infects your body when you’re sick, a computer virus spreads itself through your computer. Viruses install themselves without your consent. Once a virus infects your computer, it replicates itself into other programs, files, or areas of your hard drive. They can steal processing power, access personal information, corrupt data, or log your keystrokes.


Spyware does exactly what its name suggests: It spies on you. Some spyware tracks your movements as you use your computer and the Internet. Other kinds log your information and collect personal data. Spyware does this without your knowledge or consent, and it is often passing this information on to a third party who intends to use your data in illegal ways. Spyware rarely works alone – it often comes with some of the other malware we’re defining here.

Trojan Horse

Like the horse that masqueraded as a gift but actually carried soldiers into the city, Trojan horse malware looks like legitimate, useful software. Trojans often allow someone else to access your computer, and their activity can leave your computer running noticeably slower. Using their newly acquired remote access, the hacker could log your keystrokes, watch your screen, steal your personal data, access your files, watch your webcam, or use your computer as part of their larger plan.

Computer Worm

Computer worms are a standalone type of malware whose goal is to replicate itself in order to spread to other computers, especially other computers on a network. Worms don’t need to attach themselves to an existing program, and though they don’t always cause damage, they more often do. A worm could create an access point for other types of malware to exploit, so while they may not damage your system by themselves, they allow other type of malware to do so.


Malware designers are getting more and more creative, and ransomware is one of their newest creations. We warned you about Cryptolocker last fall and Cryptowall a couple of weeks ago. These are ransomware programs that install themselves on your computer, encrypt your files, and then hold them hostage until you pay for a key to unencrypt the files. (A key, by the way, that may or may not do what it promises.) Not all ransomware encrypts your files – some merely restrict your access to your computer, software, or files and then demands a ransom be paid before you can access them again.

Protecting Yourself

There are several steps you can take to protect your computers and network:

  • Install antivirus software and keep it up to date. As new malware is released, your antivirus software needs to be updated with that information. If your antivirus software doesn’t know about a threat, it can’t protect you from it.
  • Install a firewall. Software and hardware firewalls are designed to protect your computer or computer system from incoming attacks.
  • Keep up with security updates. Software, hardware, and operating system manufacturers will occasionally release security updates for your devices. Install them and keep everything up to date. Hackers exploit weaknesses in security, and if you don’t install updates, you’re leaving your system wide open for attack.
  • Be skeptical about email. In past Tech Talk blog posts about spam and phishing, we advised you to be wary as you read your email. Don’t open unexpected attachments or click links in an email. If it looks too good to be true, it is! Many types of malware are spread through email – in infected attachments or through suspicious websites.
  • Educate yourself and your employees. Know how to protect yourself and educate your employees on safe email and Internet use. Not sure where to start? Let PNSolutions lead a workshop for your business! Education is one of the cornerstones of our work.
  • Back up your files. It's easier to recover your files and data if you regularly back it up somewhere -- preferably offsite. Not sure where to start? Let PNSolutions help.

Concerned about the security of your computer and network? Infected by a virus or other kind of malware? We’re security experts here at PNSolutions, and we can help you protect yourself from an attack or recover from one. We can even design a workshop to educate you and your employees on safe email and Internet use. Contact us today!

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