Oliver, a skilled hacker, was hired by a competitor to gather confidential information from Sarah,...

Option B. Dictionary attack is the best answer because the attacker used a precompiled list of common passwords and tested them against the login page. That is the defining pattern of a dictionary attack: trying likely password candidates from a prepared wordlist rather than exhaustively attempting every possible combination. CHFI v11 includes password-related attack and analysis concepts within its investigation scope, and this scenario matches the classic distinction between dictionary and brute-force methods.

A brute-force attack would attempt all possible character combinations systematically, which is broader and usually more time-consuming than using a list of common passwords. A keylogger would capture keystrokes from the victim’s device, which is not what happened here. Cryptanalytic attack refers to attacking cryptographic mechanisms, not simply testing common passwords against a login page.

From a CHFI perspective, understanding the difference between password-guessing methods is important because it helps investigators interpret authentication logs and attacker behavior. Since Oliver relied on a text file of frequently used passwords and tested them one by one, the technique most accurately described is a dictionary attack .