CEH Practice Question: Malware, Social Engineering and Network Attacks
Which type of malware spreads by replicating itself across a network without requiring a host file to attach to?
⚠ Common exam trap
A common trap on the CEH exam is confusing 'self-replication' with 'requires a host file'—a worm replicates independently across a network, while a virus must attach to a host file to propagate.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
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Worm
A worm is a standalone malware that replicates itself across a network without needing a host file, exploiting vulnerabilities or using network protocols like SMB, RDP, or email to spread autonomously. Unlike viruses, worms do not attach to a host program; they self-propagate via network connections, often consuming bandwidth and system resources.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Trojan
Why it's wrong here
A Trojan disguises itself as legitimate software and requires user execution; it does not self-replicate across a network. It is tempting because Trojans spread through networks via user action, but the self-replicating, host-free mechanism described is a worm's defining characteristic.
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Ransomware
Why it's wrong here
Ransomware encrypts files and demands payment; it does not self-replicate across a network without a host. It is tempting because ransomware spreads via network shares and exploits, but propagation there relies on delivery mechanisms, not autonomous host-free replication.
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Worm
Why this is correct
A worm self-replicates and propagates across networks autonomously, exploiting vulnerabilities or credentials without needing a host file to attach to. Viruses require a host file, so the worm uniquely matches the no-host, network-spreading criterion in the stem.
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Virus
Why it's wrong here
A virus requires a host file to attach to and propagate; it cannot replicate across a network without one. It is tempting because viruses self-replicate, but the host-free, network-propagating mechanism in the stem is a worm, not a virus.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.