What does NTSTATUS 0xC000017F (STATUS_LM_CROSS_ENCRYPTION_REQUIRED) mean?

 
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STATUS_TOO_MANY_SIDS STATUS_KEY_HAS_CHILDREN

STATUS_LM_CROSS_ENCRYPTION_REQUIRED

The selected legacy password-change method expects LM proof data

Some historical SAMR methods contain separate NT and LAN Manager encrypted values. This result indicates that the server or operation requires the LM-side field. The requirement reflects the chosen compatibility method, not a recommendation to retain LM password hashes.

Modern deployments should determine why this obsolete method was selected. Enabling LM hash storage or weakening passwords has security consequences. Prefer a newer Unicode/AES password-change method or update the client and account authority.

What to inspect

  • Identify the exact SAMR method and whether the server is a legacy or compatibility implementation.
  • Check policy controlling LAN Manager hash storage and authentication level.
  • Move to a supported password-change protocol instead of fabricating an LM value.

References


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