312-50V9 · Question #567
You are attempting to crack LM Manager hashed from Windows 2000 SAM file. You will be using LM Brute force hacking tool for decryption. What encryption algorithm will you be decrypting?
The correct answer is B. DES. The LAN Manager (LM) hash algorithm uses DES to encrypt a fixed plaintext with each half of the password as the key, making DES the algorithm being attacked during LM hash cracking.
Question
You are attempting to crack LM Manager hashed from Windows 2000 SAM file. You will be using LM Brute force hacking tool for decryption. What encryption algorithm will you be decrypting?
Options
- AMD4
- BDES
- CSHA
- DSSL
How the community answered
(27 responses)- B89% (24)
- C7% (2)
- D4% (1)
Why each option
The LAN Manager (LM) hash algorithm uses DES to encrypt a fixed plaintext with each half of the password as the key, making DES the algorithm being attacked during LM hash cracking.
MD4 is the algorithm used to produce NTLM hashes from the Unicode password, not LM hashes.
LM hashing works by converting the password to uppercase, padding it to 14 characters, and splitting it into two 7-byte halves. Each 7-byte half is then used as a DES key to encrypt the fixed constant string 'KGS!@#$%', producing two 8-byte ciphertext blocks that are concatenated into the 16-byte LM hash. A brute-force tool targeting the SAM file LM hash is therefore breaking DES encryption, not a hash or asymmetric cipher.
SHA (Secure Hash Algorithm) is not used in any stage of LM hash computation.
SSL is a transport-layer security protocol and plays no role in how LM hashes are computed or stored.
Concept tested: LM hash construction using DES encryption
Source: https://learn.microsoft.com/en-us/troubleshoot/windows-server/windows-security/prevent-windows-store-lm-hash-password
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