Johnson is a professional hacker who targeted an organization’s customers and decided to crack their system passwords. In this process, he found a list of valid customers, created a list of possible passwords, ranked the passwords from high to low probability, and started keying in each password in the target system until the correct password is discovered.

Johnson is a professional hacker who targeted an organization’s customers and decided to crack their system passwords. In this process, he found a list of valid customers, created a list of possible passwords, ranked the passwords from high to low probability, and started keying in each password in the target system until the correct password is discovered.

Identify the type of attack performed by Johnson in the above scenario.
A . Password guessing
B . Rainbow table attack
C . Dictionary attack
D . Brute force attack

View Answer

Answer: C

Explanation:

The scenario described involves Johnson using a list of possible passwords, which he has ranked by probability, and systematically entering them into the system to discover the correct one. This method is known as a dictionary attack, where an attacker uses a prearranged list of likely passwords―often derived from lists of common passwords or phrases―and tries them one by one. This is different from a brute force attack, which would involve trying all possible combinations, and a rainbow table attack, which uses precomputed hash values to crack encrypted passwords. Password guessing is a less systematic approach that doesn’t necessarily involve a ranked list of passwords.

Reference: The information provided aligns with the knowledge domains of the EC-Council Certified Security Specialist (E|CSS) program, which includes understanding various types of attacks and their methodologies as part of the ethical hacking and network defense curriculum1.

The scenario described involves Johnson, who has a list of valid customers and a list of possible passwords ranked by probability, which he uses to systematically attempt to log in to the target system. This method is known as a dictionary attack. In a dictionary attack, the hacker uses a list of likely passwords―often derived from lists of common passwords or phrases―and tries them one by one. This differs from a brute force attack, which involves trying all possible combinations of characters until the correct one is found.

A dictionary attack is more efficient than brute force because it relies on the likelihood that people will use common words or phrases for passwords, making it a targeted approach based on probability rather than random attempts. Therefore, the correct answer is C, as it best describes the technique used by Johnson in the given scenario.