312-50V9 · Question #101
What statement is true regarding LM hashes?
The correct answer is D. LM hashes are not generated when the password length exceeds 15 characters. LAN Manager (LM) hashes have specific well-known weaknesses in how they are generated, including character normalization, fixed splitting, and a length threshold that disables their creation.
Question
What statement is true regarding LM hashes?
Options
- ALM hashes consist in 48 hexadecimal characters.
- BLM hashes are based on AES128 cryptographic standard.
- CUppercase characters in the password are converted to lowercase.
- DLM hashes are not generated when the password length exceeds 15 characters.
How the community answered
(34 responses)- A6% (2)
- B3% (1)
- C3% (1)
- D88% (30)
Why each option
LAN Manager (LM) hashes have specific well-known weaknesses in how they are generated, including character normalization, fixed splitting, and a length threshold that disables their creation.
LM hashes are 32 hexadecimal characters (16 bytes / 128 bits), not 48 hexadecimal characters.
LM hashes are computed using DES (Data Encryption Standard), not AES128; DES is applied to each 7-character password half using a fixed constant as the key.
The LM algorithm converts lowercase characters TO uppercase before hashing, not the reverse, which significantly reduces the keyspace and weakens the hash.
Windows does not generate or store an LM hash when a password exceeds 14 characters in length; instead it stores a null placeholder. This was introduced as a security measure because LM hashes of long passwords cannot be split into the standard two 7-character chunks used by the algorithm.
Concept tested: LAN Manager hash generation weaknesses and limitations
Source: https://learn.microsoft.com/en-us/troubleshoot/windows-server/windows-security/prevent-windows-store-lm-hash-password
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