Security Compliance

Is it safe to disable NTLM v1 while using ARM?

Use of NTLM v1 in ARM.

First published date

10/19/2021 1:59 PM

Last published date

10/19/2021 1:59 PM

Overview

This article provides details of the use of NTLM v1 in ARM and also steps on how to disable it.

Product section

Access Rights Manager

Resolution

The NTLM v1 is not utilized by ARM and can safely be disabled in the server(s) where ARM is deployed. To disable NTLM v1 follow the steps below:
 
  1. Click on Start > Run and type in gpedit.msc to open the Group Policy
  2. Navigate to Local Computer Policy > Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options
  3. Find the policy Network Security: LAN Manager authentication level
  4. Right-click on this policy and choose Properties
  5. Select option Send NTLMv2 response only/refuse LM & NTLM
  6. Click OK and confirm the change
  7. Close the Group Policy
  8. A change shall take immediate effect, but you may also restart the server.

More about NTLM can be found below:

https://docs.microsoft.com/en-us/windows-server/security/kerberos/ntlm-overview (© 2021 Microsoft, available at https://docs.microsoft.com/, obtained on October 19th, 2021)