What is malware? Everything you need to know about malicious software and viruses, and how to protect your computer

Protect yourself from online attacks that threaten your identity, your files, your system, and your financial well-being.




a person sitting at a table using a laptop computer: There are many different kinds of malware to protect your PC from. Hill Street Studios/Getty Images


© Hill Street Studios/Getty Images
There are many different kinds of malware to protect your PC from. Hill Street Studios/Getty Images

  • Malware refers to any software that is designed with malicious intent.
  • Malware includes viruses, worms, adware, spyware, ransomware and other varieties — they all work differently but tend to cause similar symptoms and behaviors on your PC. 
  • Here’s everything you need to know to understand malware and protect yourself from it.  
  • Visit Business Insider’s Tech Reference library for more stories.

Malware refers to any software that is designed with malicious intent — it generally aims to damage, destroy, or steal data, take control of computers, and aid in criminal activity. There are many kinds of malware, so what any specific example of malware depends on what it was created to do. 

Malware has a long history on the PC, with the first known example dating back to 1971 when a virus called Creeper was created. Historically, Windows computers are considered most at risk from malware — not because Macs and Linux are significantly more secure, but because the overwhelming majority of computers run Windows and so hackers and criminals tend to target those machines. 

The different types of malware

Malware is an umbrella term for malicious software. These are the most common kinds of malware and the ones you are most likely to be infected by:

  • Virus: Many people mistakenly refer to all malware as a virus, but in reality, a virus is just one, albeit very common, kind of malware. A virus is malware with the ability to replicate itself. For details, read our article on computer viruses. 
  • Ransomware: Ransomware became one of the most potent and common forms of malware in the last decade — it encrypts all the files on a computer and demands a ransom to unlock them. You can read more in our article on how to avoid ransomware
  • Worm: Similar to a virus, a computer worm replicates itself, but does it automatically, without any need for human interaction. You can learn more by reading our article on protecting yourself from computer worms.
  • Spyware: This kind of malware steals sensitive information from your PC and sends it to third parties without…

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