CEH Enumeration and System Hacking Practice Question
An attacker uses a tool that precomputes hash chains for common passwords to crack password hashes quickly. Which technique is the attacker employing?
⚠ Common exam trap
Watch out — candidates often confuse a rainbow table attack with a dictionary attack, because both involve lists of passwords, but the key distinction is precomputation versus real-time hashing.
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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Rainbow table attack
Rainbow table attack. This technique involves precomputing hash chains for common passwords and storing them in a table, allowing the attacker to reverse password hashes quickly by looking up the hash in the table rather than computing hashes on the fly. The tool described matches the core concept of a rainbow table, which uses a time-memory trade-off to crack hashes efficiently.
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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Dictionary attack
Why it's wrong here
A dictionary attack involves hashing a predefined list of common words, phrases, and previously leaked passwords, then comparing these generated hashes against the target hash. While it uses a pre-compiled *list* of potential passwords, it does not rely on precomputed *hash chains* or complex mathematical functions to reverse hashes. Its effectiveness is limited to passwords found within its dictionary, making it unsuitable for cracking hashes derived from arbitrary character combinations.
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Brute-force attack
Why it's wrong here
A brute-force attack systematically attempts every possible character combination within a defined character set and length until the correct password is found. This method generates and hashes each potential password in real-time, comparing it against the target hash without relying on any precomputed data structures like hash chains or lookup tables. Consequently, it is computationally intensive and significantly slower than methods utilizing precomputation, especially for longer or more complex passwords.
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Hybrid attack
Why it's wrong here
A hybrid attack combines elements of dictionary attacks with brute-force techniques by systematically modifying words from a dictionary list. It typically involves appending or prepending numbers, symbols, or altering character cases to dictionary words, then hashing these variations for comparison. While more comprehensive than a pure dictionary attack, it still generates and hashes candidates dynamically and does not utilize precomputed hash chains or large lookup tables for efficient hash reversal.
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Rainbow table attack
Why this is correct
A rainbow table attack leverages large, precomputed tables containing hash chains generated using a specialized reduction function. These tables map hashes back to their original plaintext values by performing a lookup rather than real-time computation. When a target hash is found within the table, the corresponding chain is traversed to recover the original password, making it highly efficient for cracking hashes quickly without needing to recompute every possible password combination.
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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.