SMB Signing Enforcement (NIST CSF)

General/Technical Documentation

Purpose

This article provides a tiered troubleshooting framework for Helpdesk technicians and IT Coordinators to verify, force, and diagnose SMB signing compliance following the NIST CSF security enforcement.

General Information

 

Helpdesk - Basic Troubleshooting

Personnel: Helpdesk Technicians

Goal: Verify the workstation policy and refresh it if missing.

Step 1: Check Policy Status

  1. Open PowerShell as Administrator and copy/paste this exact command:
Get-SmbClientConfiguration | Select-Object RequireSecuritySignature
  1. If it says True: The workstation is configured correctly. STOP. Do not proceed to Step 2. If the user still has issues, gather the Computer Name and route the ticket to the Departmental ITC.
  2. If it says False: The workstation is missing the security update. Proceed to Step 2.

Step 2: Force Policy Refresh

  1. In the same window, copy and paste:Uploaded Image (Thumbnail)
  2. Restart the computer. A reboot is required for SMB changes to take effect.
  3. Rerun Step 1 (Get-SmbClientConfiguration | Select-Object RequireSecuritySignature) to verify if the value changed to True.
  4. If the issue persists after the reboot, gather the Computer Name and route the ticket to the Departmental ITC.

ITC - Advanced Diagnostics

Personnel: Departmental IT Coordinators (ITCs)

Goal: To be used when a workstation is confirmed "True" in Tier 1 but still cannot connect to a specific server or device.

A. Verify Departmental Server Settings

Servers must have both the Client and Server SMB signing requirements enabled. Run these on the Server using PowerShell as Administrator:

PowerShell 

# Verify Server-side enforcement
Get-SmbServerConfiguration | Select-Object RequireSecuritySignature

# Verify Client-side enforcement (for outbound server traffic)
Get-SmbClientConfiguration | Select-Object RequireSecuritySignature

  • Requirement: Both must return True. If either is False, the server is not compliant with the new security standard.

B. Check the Live Connection & SMB Version

Run this on the Workstation using PowerShell as Administrator while the user attempts to access the share:

PowerShell 

Get-SmbConnection | Select-Object ServerName, Signed, Dialect

How to Interpret the "Dialect" (SMB Version):

  • Dialect 1.x (SMB 1.0): Legacy Alert. This device uses an outdated protocol that does not support modern signing.

  • Signed = False: Indicates a signing mismatch. Proceed to the manual force commands.

C. Manual Force Commands (Outliers Only)

If a machine is not taking the GPO, the ITC can force it manually. Note: Both of the following commands must be run as Administrator in PowerShell.

Force Client-Side (Workstations):

PowerShell 

Set-SmbClientConfiguration -EnableSecuritySignature $true -RequireSecuritySignature $true -Force

Force Server-Side (Departmental Servers):

PowerShell 

Set-SmbServerConfiguration -EnableSecuritySignature $true -RequireSecuritySignature $true -Force

Escalation Requirements

If the ITC cannot resolve the issue using the Tier 2 diagnostics, escalate to CIS or IT Security with the following:

  1. Computer Name and IP Address.

  2. Physical Location (Building/Room).

  3. Primary Contact/Owner for the equipment.

  4. PowerShell Results from the Get-SmbConnection command (must be run as Administrator).

Technical Reference(s)

Some contextual information about the links so as not to waste users time clicking something they don't need. 

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