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Edit File: Authentication.Mechanisms.NTLM.txt

NTLM ==== There are four authentication submethods inside the NTLM: 1. LM: server nonce only, highly vulnerable to MITM and rogue server attacks. 2. NTLM: different algorithm, almost equally vulnerable as LM today. 3. NTLM2: server and client nonce, but MITM can force downgrade to NTLM/LM. 4. NTLMv2: server and client nonce, MITM can't force downgrade. NTLM <password scheme> [Authentication.PasswordSchemes.txt] is required for NTLM, NTLM2 and NTLMv2. NTLMv2 can not be negotiated. It must be explicitly enabled on the client side by setting registry key below to at least 3: * Win9x: 'HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\LMCompatibility' * WinNT: 'HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\LMCompatibilityLevel' Dovecot's NTLM logic is: 1. If we have only LM password scheme, try LM authentication; 2. If client sends LM response only (some very old clients do it), try LM too; 3. If NTLMv2 is guessed (using client response length), try NTLMv2; 4. If NTLM2 was negotiated, try it; 5. Otherwise try NTLM. For more information about NTLM internals, see http://ubiqx.org/cifs/ and http://davenport.sourceforge.net/ntlm.html (This file was created from the wiki on 2018-05-23 04:42)