Malware types (virus, worm, trojan, ransomware) in Cybersecurity - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Malware Propagation

Which malware type is known for spreading itself automatically across networks without needing a user to run a program?

A Worm

B Virus

C Trojan

D Ransomware

💡 Hint

Think about malware that moves independently through networks.

Worms can spread automatically over networks without user action, unlike viruses or trojans which need user interaction.

📋 Factual

intermediate

Identifying Malware Behavior

Which malware type disguises itself as legitimate software to trick users into installing it?

A Ransomware

B Worm

C Virus

D Trojan

💡 Hint

Consider malware that pretends to be something safe.

Trojans appear as normal programs but carry harmful code, tricking users into installing them.

🔍 Analysis

advanced

Comparing Malware Effects

Which malware type primarily aims to block access to data or systems until a ransom is paid?

A Ransomware

B Virus

C Worm

D Trojan

💡 Hint

Think about malware that demands money to restore access.

Ransomware encrypts or locks data and demands payment to unlock it, unlike other malware types.

❓ Reasoning

advanced

Distinguishing Malware Characteristics

Which statement best describes the difference between a virus and a worm?

A A virus can spread without user action, but a worm needs a user to run it.

B A worm attaches itself to files, while a virus spreads independently.

C A virus requires user action to spread, while a worm spreads automatically over networks.

D Both virus and worm require user action to spread.

💡 Hint

Consider how each malware spreads and if user action is needed.

Viruses need a user to run infected files to spread, while worms spread automatically without user help.

🚀 Application

expert

Identifying Malware from Behavior Description

A user downloads a free game from an unknown website. After installation, their files become encrypted and a message demands payment to unlock them. Which malware type is responsible?

A Trojan

B Ransomware

C Virus

D Worm

💡 Hint

Focus on the encryption and payment demand after installing software.

The behavior describes ransomware, which encrypts files and demands payment to restore access.

Practice

1. Which type of malware replicates itself to spread to other computers without needing to attach to a program?

easy

A. Worm

B. Virus

C. Trojan

D. Ransomware

Solution

1. Step 1: Understand malware replication methods

   Viruses need to attach to files, but worms can spread independently over networks.

2. Step 2: Identify malware that self-replicates without a host

   Worms are known for spreading themselves without needing to attach to other programs.

3. Final Answer:

   Worm -> Option A

4. Quick Check:

   Self-replicating malware without host = Worm [OK]

Hint: Worms spread alone, viruses need hosts [OK]

Common Mistakes:

• Confusing virus with worm
• Thinking trojans self-replicate
• Mixing ransomware with spreading behavior

2. Which of the following correctly describes a Trojan horse in malware terms?

easy

A. Malware that replicates itself over networks

B. Malware that encrypts files and demands payment

C. Malware that spreads by attaching to files

D. Malware disguised as legitimate software

Solution

1. Step 1: Define Trojan horse malware

   Trojans appear as normal software but hide harmful actions inside.

2. Step 2: Match description to options

   Malware disguised as legitimate software matches the definition of a Trojan as disguised malware.

3. Final Answer:

   Malware disguised as legitimate software -> Option D

4. Quick Check:

   Trojan = disguised malware [OK]

Hint: Trojans hide inside normal-looking apps [OK]

Common Mistakes:

• Confusing ransomware with Trojan
• Thinking Trojan self-replicates
• Mixing virus and Trojan definitions

3. Consider this scenario: A malware encrypts all files on a computer and demands money to unlock them. What type of malware is this?

medium

A. Ransomware

B. Worm

C. Trojan

D. Virus

Solution

1. Step 1: Identify malware behavior described

   The malware encrypts files and demands payment to restore access.

2. Step 2: Match behavior to malware type

   Ransomware is known for encrypting files and demanding ransom.

3. Final Answer:

   Ransomware -> Option A

4. Quick Check:

   Encrypts files + demands money = Ransomware [OK]

Hint: Ransomware locks files and asks for payment [OK]

Common Mistakes:

• Confusing ransomware with virus
• Thinking Trojan encrypts files
• Mixing worm behavior with ransomware

4. A user reports their computer is slow and programs crash often. They find a malware that attaches itself to files and spreads when files are shared. Which malware type is most likely causing this?

medium

A. Trojan

B. Virus

C. Worm

D. Ransomware

Solution

1. Step 1: Analyze malware behavior

   The malware attaches to files and spreads when files are shared, causing crashes and slowdowns.

2. Step 2: Identify malware type matching this behavior

   Viruses attach to files and spread through sharing, unlike worms which spread independently.

3. Final Answer:

   Virus -> Option B

4. Quick Check:

   Attaches to files + spreads by sharing = Virus [OK]

Hint: Virus attaches to files, spreads via sharing [OK]

Common Mistakes:

• Confusing worm with virus
• Thinking Trojan spreads by itself
• Mixing ransomware symptoms with virus

5. A company wants to protect its network from malware that can spread automatically without user action and also from malware disguised as useful software. Which two malware types should they focus on preventing?

hard

A. Virus and Ransomware

B. Trojan and Virus

C. Worm and Trojan

D. Ransomware and Worm

Solution

1. Step 1: Identify malware that spreads automatically

   Worms spread automatically over networks without user action.

2. Step 2: Identify malware disguised as useful software

   Trojans appear as legitimate software but carry harmful payloads.

3. Final Answer:

   Worm and Trojan -> Option C

4. Quick Check:

   Auto-spread = Worm, disguised = Trojan [OK]

Hint: Worm spreads alone; Trojan hides in apps [OK]

Common Mistakes:

• Choosing ransomware instead of worm
• Mixing virus with Trojan
• Ignoring automatic spread behavior