How do I check NTLMv1?

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 NTLMv1 secure?

Use of the NTLMv1 protocol has a definite, adverse effect on network security and may be compromised.

What is NTLMv1 authentication?

NTLMv1 Authentication: A user signs in to a client computer with a domain name, user name, and password. The client computer creates a cryptographic hash (either NT or KM hash) of the password. The client computer sends the targeted server the user name in plain text.

Can a client use NTLMv2 in Level 1?

Clients at this setting never use NTLMv2. Servers at this setting will accept any of the three protocols. Send LM & NTLM – use NTLMv2 session security if negotiated:Level 1 allows the use of LM and NTLMv1, so it does not eliminate the vulnerabilities inherent in those protocols.

How is the NTLM2 Session protocol similar to MS-CHAPv2?

The NTLM2 Session protocol is similar to MS-CHAPv2. It consists of authentication from NTLMv1 combined with session security from NTLMv2. Briefly, the NTLMv1 algorithm is applied, except that an 8-byte client challenge is appended to the 8-byte server challenge and MD5-hashed.

How to disable NTLMv1 in LAN Manager?

Go to the GPO section Computer Configurations -> Policies -> Windows Settings -> Security Settings -> Local Policies -> Security Options and find the policy Network Security: LAN Manager authentication level. You can also disable NTLMv1 through the registry.

Where can I find most NTLMv1 logon events?

You will find most NTLMv1 logon events on the member servers that allow NTLMv1–those member servers are the key and you should target them as the point of leverage to identify which clients are using NTLMv1. You then fix the clients, fix the servers, then fix the DCs. Then find out you missed some clients and servers. Solution?