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Malware Overview and Prevention

Jul 13, 2025

Overview

This lecture introduces malware, explaining its main types, how they spread, and strategies to prevent infection.

What is Malware?

  • Malware is malicious software designed to exploit computers for illegal gain, often by stealing sensitive data.
  • Other purposes of malware include cyber vandalism, espionage, activism, and warfare.

How Malware Spreads

  • Malware can enter computers from file downloads, infected websites, or email attachments/links.
  • Peer-to-peer file sharing and opening executable files are common infection methods.

Types of Malware

  • Viruses attach to executable files and spread when infected programs are opened.
  • Trojans appear as legitimate software and require users to run them, enabling theft or remote control.
  • Ransomware locks your device or data, demanding payment to restore access.
  • Spyware secretly tracks user activity, including keystrokes, to steal passwords and sensitive information.
  • Worms are standalone programs that self-replicate, spreading across networks without user action.

Differences Between Viruses and Worms

  • Viruses need a host file and user action to spread, while worms duplicate independently using networks.
  • Worms exploit weak security, outdated software, and lack of antivirus protection.

Protecting Against Malware

  • Regularly update your operating system with patches and updates.
  • Use trusted antivirus software to detect and block malware.

Key Terms & Definitions

  • Malware — malicious software aimed at exploiting or harming computer systems.
  • Virus — malware attached to executable files, requires user action to spread.
  • Trojan — deceptive software that appears legitimate and tricks users into running it.
  • Ransomware — malware that locks devices or files and demands payment for release.
  • Spyware — software that secretly collects information from a user's computer.
  • Worm — standalone malware that self-replicates and spreads across networks.

Action Items / Next Steps

  • Keep your operating system and software updated with the latest security patches.
  • Install and regularly update antivirus software from a reputable vendor.