Quick Answer
The answer is a worm. Unlike viruses or trojans, a worm is a standalone malware type that self-replicate without a host file, propagating across networks by exploiting vulnerabilities in operating systems or weak credentials. This technical distinction is critical because worms do not need to attach themselves to an existing program or document; they operate independently, consuming bandwidth and system resources as they spread. On the Certified Ethical Hacker CEH exam, this concept tests your understanding of malware propagation methods, often appearing in questions that contrast worms with viruses or logic bombs. A common trap is confusing worms with viruses—remember that viruses require a host file to attach to, while worms are self-contained. For a quick memory tip, think of the phrase “Worms Walk Alone” to recall that worms are standalone and spread without a host.
This CEH practice question tests your understanding of malware, social engineering and network attacks. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which of the following is a type of malware that spreads by replicating itself across a network without requiring a host file?
Worm
Worms are self-replicating and do not need a host file.
Trojan
Why wrong: Trojans disguise as legitimate software but do not replicate.
Ransomware
Why wrong: Ransomware encrypts files for ransom but typically does not self-replicate.
Virus
Why wrong: A virus requires a host file to attach itself.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Worm
A worm is a standalone malware that replicates itself to spread to other computers, often via network vulnerabilities.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Worm
Why this is correct
Worms are self-replicating and do not need a host file.
Related concept
Read the scenario before looking for a memorised answer.
Trojan
Why it's wrong here
Trojans disguise as legitimate software but do not replicate.
Ransomware
Why it's wrong here
Ransomware encrypts files for ransom but typically does not self-replicate.
Virus
Why it's wrong here
A virus requires a host file to attach itself.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CEH exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which CEH exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Malware, Social Engineering and Network Attacks — This question tests Malware, Social Engineering and Network Attacks — Read the scenario before looking for a memorised answer..
The correct answer is: Worm — A worm is a standalone malware that replicates itself to spread to other computers, often via network vulnerabilities.
Identify which CEH exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO types of malware typically require user interaction (e.g., opening a file or clicking a link) to activate? (Select two.)
mediumWhy A: Trojans typically require user interaction to execute, and ransomware often requires user action (clicking a link or opening an attachment) to trigger. Worms and polymorphic viruses can spread without user interaction, though viruses generally need a host file.
Last reviewed: Jun 21, 2026
This CEH practice question is part of Courseiva's free EC-Council certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CEH exam.
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