The correct answer is D. Brute force. A brute-force attack is a password-cracking method that systematically attempts every possible combination of characters until the correct password is discovered. Because it does not rely on precompiled wordlists, common passwords, or previously generated hash databases, it is considered the most exhaustive and time-consuming password-cracking technique.
In CEH password-attacking concepts, a dictionary attack is generally faster because it uses a predefined list of commonly used passwords and words. Rainbow tables are even faster in many situations because they rely on precomputed hash values that can be matched against captured password hashes. Shoulder surfing is not a technical password-cracking method; it involves directly observing a user entering credentials.
The effectiveness and duration of a brute-force attack depend on password complexity, length, character set, account lockout policies, and available computing power. Strong passwords containing uppercase letters, lowercase letters, numbers, and special characters significantly increase the number of possible combinations, making brute-force attacks far more difficult and time-consuming.
CEH Exam Tip:
Dictionary Attack = Faster, wordlist-based.
Rainbow Tables = Precomputed hash lookup.
Brute Force = Tries every possibility; most time and effort required.
Shoulder Surfing = Social engineering observation technique.
Therefore, Brute Force is the correct answer.
