eJPT Password Attacks and Cracking 3 — Questions and Answers
Question 1: What purpose does salting a password hash serve?
- It makes the hash shorter and faster to compute
- It adds a random value to the password before hashing, defeating precomputed rainbow tables (Correct answer)
- It encrypts the hash using AES
- It converts the hash to base64 encoding
Correct answer: It adds a random value to the password before hashing, defeating precomputed rainbow tables
A salt is a random value appended or prepended to a password before hashing, ensuring identical passwords produce different hashes and defeating rainbow table attacks.
Question 2: Which Hydra flag specifies the target username during a brute-force attack?
- -u
- -l (Correct answer)
- -U
- -n
Correct answer: -l
The -l flag in Hydra specifies a single username to target, while -L specifies a file containing multiple usernames.
Question 3: What type of attack involves testing a few common passwords against many accounts to avoid account lockouts?
- Credential stuffing
- Password spraying (Correct answer)
- Brute-force attack
- Pass-the-hash
Correct answer: Password spraying
Password spraying tests a small set of common passwords (like 'Password1!') across many accounts, staying below lockout thresholds by limiting attempts per account.
Question 4: Which John the Ripper flag displays the cracked passwords found so far?
- john --show (Correct answer)
- john --crack
- john --dump
- john --output
Correct answer: john --show
Running 'john --show <hashfile>' displays all previously cracked passwords stored in John's pot file for the given hash file.
Question 5: What is credential stuffing?
- Embedding credentials into compiled binaries
- Using leaked username/password pairs from one breach to try logging into other services (Correct answer)
- Stuffing extra characters into passwords to bypass length limits
- Adding fake credentials to a database to detect attackers
Correct answer: Using leaked username/password pairs from one breach to try logging into other services
Credential stuffing exploits password reuse by testing username/password pairs leaked from one service against other platforms.
Question 6: Which hash format does Windows NTLM use?
- SHA-1
- bcrypt
- MD4 (Correct answer)
- SHA-256
Correct answer: MD4
Windows NTLM hashes are computed using the MD4 algorithm applied to the UTF-16LE encoded password.
Question 7: What does the Hashcat -m flag specify?
- The maximum number of password attempts
- The hash type or algorithm to crack (Correct answer)
- The mask pattern for brute-force
- The minimum password length
Correct answer: The hash type or algorithm to crack
In Hashcat, -m specifies the hash type (e.g., -m 1000 for NTLM, -m 0 for MD5), telling it which algorithm to use during cracking.
eJPT Password Attacks and Cracking 3
What purpose does salting a password hash serve?