Unit 9.5: Understanding Malware: Viruses, Worms, and Trojans | IT 231 Slides

Learning Objectives 🎯

• ✅ Define what malware is and its purpose.
• ✅ Differentiate between a virus, a worm, and a Trojan horse.
• ✅ Describe the significant threat of ransomware.
• ✅ Identify the primary method of protection against malware.

What is Malware? 🔍

It's a general term for a wide variety of digital threats.

• Viruses
• Worms
• Trojan Horses
• Ransomware
• Spyware

The Virus 🦠

• Needs a Host: Cannot exist or spread on its own. It requires a host program to run.
• Replication: When the host program is executed, the virus runs and can replicate itself to infect other programs on the system.
• Example: An infected Microsoft Word macro that runs when you open a document.

The Worm 🐛

• Standalone: Does not need to attach to another program to run or spread.
• Network Propagation: Exploits vulnerabilities in operating systems or networks to travel from one computer to another without human intervention.
• Impact: Often consumes significant network bandwidth, causing network slowdowns or crashes.

The Trojan Horse 🐴

• Deception is Key: Appears to be a legitimate application (e.g., a game, a utility, a software patch).
• User-Activated: Relies on the user to download and execute the program.
• Payload: Once installed, it can perform malicious actions like stealing data, installing a backdoor, or downloading other malware.

📊 At a Glance: Virus vs. Worm vs. Trojan

The Modern Menace: Ransomware 💰

1. Infection: Often delivered via a Trojan (e.g., a malicious email attachment).
2. Encryption: Silently encrypts documents, photos, and other important files.
3. Demand: A ransom note appears on the screen demanding payment, usually in cryptocurrency.

Practical Application: The Threat in Nepal

🛡️ Primary Defense: How to Protect Yourself

Antivirus software performs several critical functions:

• Scans: Actively checks files and programs for known malware signatures.
• Removes: Quarantines or deletes malicious files it discovers.
• Prevents: Monitors system activity to block new infections in real-time.

Also critical: Keep your operating system and all applications updated with the latest security patches!

Summary & Key Takeaways

• Malware is a broad term for any software designed to cause harm.
• A virus needs a host program to spread, while a worm is a standalone program that can spread on its own across networks.
• A Trojan horse deceives you into installing it by pretending to be legitimate software.
• Ransomware is a dangerous form of malware that encrypts your files and demands a payment for their release.
• Your primary defense is using up-to-date antivirus software and practicing safe computing habits.

Exam Practice: Short Answer

1. Define malware. Name any four types.
2. Differentiate between a virus and a worm.
3. What is ransomware? How can a business protect itself from it?

Exam Practice: Long Answer

1. Explain the different types of malware with examples.
2. How does malware spread? Suggest measures an organization should take to protect itself against malware.

Revise the chapter note before writing these answers.