Allow specified hosts to show Basic Authentication prompts to Office apps

UserNeeds changes for IntuneL_BasicAuthPromptBehavior

Supported on SUPPORTED_Windows7 (defined in the Windows templates)

5568.1000

What it does

This policy setting allows you to specify which hosts can show Basic Authentication sign-in prompts to Office apps. By default, all Basic Authentication sign-in prompts are blocked, and the user is shown a message that the sign-in method isn’t allowed. If you enable this policy setting, you need to enter the hosts by name, separating the host names with a semi-colon. For example: server1.contoso.com; server2.fabrikam.com. Warning: Allowing Basic Authentication sign-in prompts isn’t recommended because it’s a security risk. Basic Authentication sign-in prompts from all other hosts will be blocked and the user will be shown a message that the sign-in method isn’t allowed. If you disable or don’t configure this policy setting, all Basic Authentication sign-in prompts will be blocked, and the user will be shown a message that the sign-in method isn’t allowed. Note: This policy setting only applies to subscription versions of Office, such as Microsoft 365 Apps for enterprise, and to subscription versions of Project and Visio. For more information, see https://go.microsoft.com/fwlink/p/?linkid=2199001.

What it writes

Hive: HKEY_CURRENT_USER
Registry key: software\policies\microsoft\office\16.0\common\identity

Why it needs changes for Intune

Policy references a Windows supportedOn definition.
ADMX-INTUNE-WINDOWS-SUPPORTEDON-REFERENCE

Options

Option	Type	Registry value	Allowed values
Host names	Text	`basichostallowlist`	Up to 255 characters

Configure and deploy

Choose a state and the option values; the output below is generated from the template for exactly that.

Enabled · User · template defaults

Registry file (.reg)

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\identity]
"basichostallowlist"=hex(2):00,00

PowerShell

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Allow specified hosts to show Basic Authentication prompts to Office apps
# Name: L_BasicAuthPromptBehavior
# Scope: User
# State: Enabled
# Source: office16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\identity' -Name 'basichostallowlist' -PropertyType 'ExpandString' -Value ''

The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.
The generated payload is incomplete because one or more ADMX element values were not supplied: L_AuthenticationBasicAuthEnabledHostsID

ADMX profile candidate (OMA-URI)

./User/Vendor/MSFT/Policy/Config/ADMX_office16/L_BasicAuthPromptBehavior

Intune remediation scripts

Detection

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' { return [uint64]$actual -eq [uint64]$Expected }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Allow specified hosts to show Basic Authentication prompts to Office apps
# Name: L_BasicAuthPromptBehavior
# Scope: User
# State: Enabled
# Source: office16.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\identity' -Name 'basichostallowlist' -Kind 'ExpandString' -Expected ''
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\identity\basichostallowlist') | Out-Null
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

Remediation

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Allow specified hosts to show Basic Authentication prompts to Office apps
# Name: L_BasicAuthPromptBehavior
# Scope: User
# State: Enabled
# Source: office16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\identity' -Name 'basichostallowlist' -PropertyType 'ExpandString' -Value ''

History 1 retained release

5568.100010 Aug 2026
- Already present in the first release ChangeIntel keeps.

Template

Internal name: L_BasicAuthPromptBehavior
Namespace: office16.Office.Microsoft.Policies.Windows
Template file: office16.admx
Release: Microsoft 365 Apps 5568.1000 · file set 8be05d876aae137d…

Definition, editor controls and support

Definition

<policy class="User" displayName="$(string.L_BasicAuthPromptBehavior)" explainText="$(string.L_BasicAuthPromptBehaviorExplain)" key="software\policies\microsoft\office\16.0\common\identity" name="L_BasicAuthPromptBehavior" presentation="$(presentation.L_AuthenticationBasicAuthBehavior)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="office16.Office.Microsoft.Policies.Windows:L_SecuritySettings" />
      <supportedOn ref="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
      <elements>
        <text expandable="true" id="L_AuthenticationBasicAuthEnabledHostsID" required="false" valueName="basichostallowlist" />
      </elements>
    </policy>

Editor controls

<presentation id="L_AuthenticationBasicAuthBehavior" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <textBox refId="L_AuthenticationBasicAuthEnabledHostsID">
          <label>Host names:</label>
        </textBox>
      </presentation>

Supported platforms and category

office16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeSystem
<category displayName="$(string.L_MicrosoftOfficeSystem)" name="L_MicrosoftOfficeSystem" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
office16.Office.Microsoft.Policies.Windows:category:L_SecuritySettings
<category displayName="$(string.L_SecuritySettings)" name="L_SecuritySettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="office16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeSystem" />
    </category>
office16.Office.Microsoft.Policies.Windows:unresolved:Microsoft.Policies.Windows:SUPPORTED_Windows7
<unresolved reference="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
office16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeSystem
<category displayName="$(string.L_MicrosoftOfficeSystem)" name="L_MicrosoftOfficeSystem" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="office16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeSystem">Microsoft Office 2016</string></strings>
office16.Office.Microsoft.Policies.Windows:category:L_SecuritySettings
<category displayName="$(string.L_SecuritySettings)" name="L_SecuritySettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="office16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeSystem" />
    </category>
<strings><string id="office16.Office.Microsoft.Policies.Windows:L_SecuritySettings">Security Settings</string></strings>