Should I disable NTLM authentication?

Version NTLMv2 uses more secure encryption algorithms and allows for preventing popular NTLM attacks. NTLMv1 and LM authentication protocols are disabled by default starting with Windows 7/Windows Server 2008 R2. Thus, it’s recommended to disable NTLM Authentication in Windows Domain.

What is the impact of disabling NTLM?

If you want to turn off NTLM audit policy settings, there will be a little impacts, that is when NTLM authentication is successful or failed, no audit events will logged in Security log under Event Viewer on any DC.

Do I need NTLM?

NTLM authentication is still supported and must be used for Windows authentication with systems configured as a member of a workgroup. NTLM authentication is also used for local logon authentication on non-domain controllers.

What is NTLM disable?

The Network Security: Restrict NTLM: NTLM authentication in this domain policy setting allows you to deny or allow NTLM authentication within a domain from this domain controller. This policy setting does not affect interactive logon to this domain controller.

Why is NTLM bad?

The most critical issue with NTLM is that it does not commonly provide mutual authentication. And while this is an issue by itself, it leads to the more severe issue of NTLM being susceptible to replay and man-in-the-middle attacks. This can happen whenever a user authenticates to a server via NTLM.

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What still uses NTLM?

While NTLM is still supported by Microsoft, it has been replaced by Kerberos as the default authentication protocol in Windows 2000 and subsequent Active Directory (AD) domains.

How do you tell if you are using NTLM?

NTLM auditing

To find applications that use NTLMv1, enable Logon Success Auditing on the domain controller, and then look for Success auditing Event 4624, which contains information about the version of NTLM.

Is NTLM authentication secure?

Is NTLM secure? NTLM is generally considered insecure because it uses outdated cryptography that is vulnerable to several modes of attacks. NTLM is also vulnerable to the pass-the-hash attack and brute-force attacks.

Is NTLM enabled?

1 Answer. NT LAN Manager (including LM, NTLM v1, v2, and NTLM2) is enabled and active in Server 2016 by default, as its still used for local logon (on non-domain controllers) and workgroup logon authentication in Server 2016.

What is the main difference between NTLM and net NTLMv2?

NTLMv2 (A.K.A. Net-NTLMv2) This is the new and improved version of the NTLM protocol, which makes it a bit harder to crack. The concept is the same as NTLMv1, only different algorithm and responses sent to the server.

What ports does NTLM use?

NT LAN Manager (NTLM) is the default authentication scheme used by the WinLogon process; it uses three ports between the client and domain controller (DC): UDP 137 – UDP 137 (NetBIOS Name) UDP 138 – UDP 138 (NetBIOS Netlogon and Browsing) 1024-65535/TCP – TCP 139 (NetBIOS Session)

Is NTLMv2 vulnerable?

NTLM is a rather veteran authentication protocol and quite vulnerable for relatively easy to initiate attacks. The fact that it is not secure, doesn’t make it easier to move to a better protocol (such as Kerberos), since many functions are dependent on it.

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How do I get rid of NTLM?

You can also disable NTLMv1 through the registry. To do it, create a DWORD parameter with the name LmCompatibilityLevel and the value 0-5 in the registry key HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlLsa. Value 5 corresponds to the policy option “Send NTLMv2 response only. Refuse LM NTLM”.

Can you pass the hash with NTLMv2?

NTLM has been succeeded by NTLMv2, which is a hardened version of the original NTLM protocol. NTLMv2 includes a time-based response,which makes simple pass the hash attacks impossible.