Ethical Hacking : Basics of Malware – Virus vs Worm vs Trojan

Hi All,

Today we are going to discuss the basics of MalwareVirus vs Worm vs Trojan. We are going to see the what damage is done by malware.

We have started the series of ethical hacking articles, if you dindt got a chance to look so please visit once –

What is computer malware ?

  • It is a kind of software or malicious code
  • It is written by an unknown person or by a hacker to harm your computer
  • Some varieties of malware are – Virus, Worm, Trojan

How they transport to your computer

  • By clicking on any suspicious web link while surfing on web
  • By downloading any program that claims to be a game or cool photos
  • File shared by an anonymous user by any forum
  • By clicking on any fake bonus shared by any hacker

Damage done by malware

  • Sometime displays unwanted messages
  • Some tend to destroy program or data
  • Result in system crashes
  • Format hard disk
  • Damage data
  • Delete files
  • Encrypt complete data

How does antivirus works ?

  • Detect using a virus signature definitions
  • Comparing the file stored on fixed or removable drives (hard drives, floppy drives) against the database of known virus “signatures”

Virus vs Worm vs Trojan horse

When we click on any file malicious file then only the virus will affect your computer otherwise it cannot affect it. When a user executes a seemingly harmless file attached with malicious code, direct action viruses deliver a payload immediately

Examples of Computer Virus

  • Morris Worm
  • Nimda
  • SQL Slammer
  • Stuxnet
  • CryptoLocker
  • Conficker
  • Tinba
  • Welchia
  • Shlayer


  • A computer worm is a type of malware whose primary function is to self-replicate and infect other computers while remaining active on infected systems.
  • A computer worm duplicates itself to spread to uninfected computers. It do needs to download any file.

Examples of worm

  • Email worms
  • Instant messaging worms
  • File-sharing worms

Trojan horse

  • It is hidden in some program and when we download that program it start affecting our system. Downloading unknown free programs.
  • What looks like a free game or screensaver could really be a Trojan, especially if you find it on an untrustworthy site.
  • Visiting shady websites. Some sites only need a moment to infect your computer. Others use tricks like pretending to stream a popular movie, but only if you download a certain video codec, which is really a Trojan.

Examples of Trojan horse

  • Zeus Gameover
  • SpyEye
  • Ice IX


Thank you for reading this article 🙂

Have a nice day!!

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