Add-WMI-Remote-Readers.ps1

# Create local "WMI Remote Readers" group and grant read only permissions to WMI for it.
# NOTE: "Distributed COM Users" group membership is also needed.
$groupName = "WMI Remote Readers"
$groupDescription = "Members of this group can remotely read WMI"
$group = Get-LocalGroup -Name $groupName -ErrorAction SilentlyContinue
if ($group) {
	return
}

New-LocalGroup -Name $groupName -Description $groupDescription

# Get current ACL
Write-Host "Get Security Descriptor from WMI"
$sd = Invoke-WmiMethod -Namespace "root" -Class "__systemsecurity" -Name "GetSecurityDescriptor"
$acl = $sd.Descriptor

# Get target account WMI object
Write-Host "Finding Win32 account"
$Win32Account = Get-WmiObject -Class Win32_Account -Filter "Domain='$env:COMPUTERNAME' and Name='$groupName'"
if (-not $Win32Account) {
    Write-Error "Win32 account $env:COMPUTERNAME\$groupName not found"
    return
}

# Create access control entry
Write-Host "Creating new access control entry"
$ace=(New-Object System.Management.ManagementClass("Win32_Ace")).CreateInstance()
$ace.AccessMask = 0x20 # RemoteEnable
$ace.AceFlags = 0x2 # Inherit to sub objects
$ace.AceType = 0x0 # Allow

# The TRUSTEE structure identifies the group account to which an access control entry (ACE) applies.
# The structure can use a name or a security identifier (SID) to identify the trustee.
Write-Host "Creating new trustee"
$trustee=(New-Object System.Management.ManagementClass("Win32_Trustee")).CreateInstance()
$trustee.SidString = $Win32Account.SID
$ace.Trustee=$trustee

# Add new ACE to ACL and apply it
$acl.DACL += $ace
Write-Host "Set Security Descriptor to WMI"
Invoke-WmiMethod -Namespace "root" -Path "__systemsecurity=@" -Name "SetSecurityDescriptor" -ArgumentList $acl

# Force refresh by querying the namespace (optional step)
Get-WmiObject -Namespace $namespace -Class "__namespace" | Out-Null

Before this:

After this:

Proof that those are read-only permissions: