Learning Objectives

By the end of this chapter, you will be able to:

  • Define malware.
  • Differentiate between a virus, a worm, and a Trojan horse.
  • Describe the threat of ransomware.
  • Identify the primary method of protection against malware.

What is Malware?

Malware, short for malicious software, is any software intentionally designed to cause damage to a computer, server, client, or computer network. Malware is a general term that includes many different types of threats.

Types of Malware

  • Virus: A piece of code that attaches itself to a legitimate program. When the program is run, the virus runs too, and it can replicate itself to infect other programs.

  • Worm: A standalone program that can replicate itself and spread to other computers over a network, without needing to attach to another program.

  • Trojan Horse: A program that disguises itself as something useful or harmless, but contains malicious code. It tricks the user into installing it.

  • Ransomware: A type of malware that encrypts a user’s files and demands a ransom payment in exchange for the decryption key.

  • Spyware: Malware that secretly gathers information about a person or organization and sends it to another party.

Protection Against Malware

The best way to protect against malware is to use antivirus software. Antivirus software can scan your computer for known malware, remove it, and help to prevent new infections. It is also important to keep your operating system and all of your software up to date with the latest security patches.

Summary

Malware is a broad category of malicious software that includes viruses, worms, Trojan horses, and ransomware. Viruses attach to programs, while worms can spread on their own. Trojans disguise themselves as legitimate software. Ransomware holds your data hostage. The most important defense against all of these threats is to use up-to-date antivirus software and to be cautious about what you download and install.

Key Takeaways

  • Malware is software designed to cause harm.
  • A virus needs a host program; a worm is standalone.
  • A Trojan horse tricks you into installing it.
  • Ransomware encrypts your files and demands payment.
  • Antivirus software is the primary defense against malware.

Discussion Questions

  1. What is the main difference between a virus and a worm?
  2. Why is ransomware such a dangerous and effective type of malware?
  3. Besides using antivirus software, what are some other good habits to practice to avoid malware infections?