CEH Practice Question: Advanced Topics: Wireless, Cloud, IoT, Cryptography

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Dictionary attack

  Why it's wrong here

  A dictionary attack is a brute-force variant where an attacker attempts to guess passwords by systematically trying entries from a pre-compiled list of common words, phrases, and previously leaked credentials. This method targets authentication mechanisms by attempting to match known plaintext values to a user's password, rather than directly exploiting cryptographic hash collisions. It aims to gain unauthorized access by guessing the secret, not by finding two different inputs that produce the same hash output.

• ✗

  Downgrade attack

  Why it's wrong here

  A downgrade attack, often executed as a man-in-the-middle (MITM) attack, forces a system to abandon a more secure communication protocol or cryptographic algorithm in favor of an older, weaker, or less secure version. The attacker intercepts the initial protocol negotiation and manipulates it to trick both parties into using a vulnerable mode, making subsequent data interception or decryption easier. This attack exploits protocol negotiation weaknesses, not the mathematical properties of hash functions to find collisions.

• ✓

  Birthday attack

  Why this is correct

  The birthday attack is a cryptographic attack that exploits the mathematics behind the birthday paradox to find collisions in hash functions more efficiently than a brute-force search. It works by generating a large number of distinct inputs and their corresponding hash outputs, then searching for two inputs that produce the same hash value. This probabilistic method significantly reduces the computational effort required to find a hash collision, making it a direct threat to the collision resistance property of hash functions.

• ✗

  Replay attack

  Why it's wrong here

  A replay attack involves an attacker intercepting a valid data transmission, such as an authentication token or a transaction request, and then retransmitting it later to deceive the system into performing an unauthorized action. This attack exploits the lack of freshness or nonces in communication protocols, allowing the attacker to bypass authentication or authorization without needing to decrypt or forge the original message. It focuses on reusing legitimate, captured data rather than finding weaknesses in cryptographic hash functions to generate collisions.

Go deeper

Related to this question