Control how Office handles form-based sign-in prompts

UserNeeds changes for IntuneL_AuthenticationFBABehavior

Supported on SUPPORTED_Windows7 (defined in the Windows templates)

5568.1000

What it does

This policy setting controls how Office applications handle form-based sign-in prompts. If you enable this policy setting, you must choose one of the following options: Block all prompts Ask the user what to do for each new host Show prompts only from allowed hosts If you select “Block all prompts” then no form-based sign-in prompts are shown to the user and the user is shown a message that the sign-in method isn’t allowed. If you select “Ask the user what do for each new host” then the user is asked for each new host whether the user wants to sign-in to the host. If the user has previously signed-in to a host, a form-based sign-in prompt is shown for that host. Also, form-based sign-in prompts are shown for any hosts specified by the “Specify hosts allowed to show form-based sign-in prompts to users” setting. If you select “Show prompts only from allowed hosts” then form-based sign-in prompts are shown only from hosts that have been specified by the additional “Specify hosts allowed to show form-based sign-in prompts to users” setting. Form-based sign-in prompts from all other hosts are blocked and the user is shown a message that the sign-in method isn’t allowed. Note: If you don’t configure the “Specify hosts allowed to show form-based sign-in prompts to users” setting or don’t specify any hosts in that setting, then the behavior of the “Show prompts only from allowed hosts” option will be the same as if you selected the “Block all prompts” option. If you disable or don’t configure this policy setting, all form-based sign-in prompts are blocked and the user is shown a message that the sign-in method isn’t allowed. But users are able to change the behavior for form-based sign-in prompts by going to File > Options > Trust Center > Trust Center Settings > Form-based sign-in. 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.

What it writes

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

Why it needs changes for Intune

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

Security baselines

Microsoft's Microsoft 365 Apps for Enterprise 2512 sets this to Enabled, in its GPO “MSFT Microsoft 365 Apps v2512 - User”.

Behavior: Set to “Block all prompts” (1).
Specify hosts allowed to show form-based sign-in prompts to users: Set to “”.

Read from the registry.pol files in the baselines' GPO backups, downloaded from Microsoft's Security Compliance Toolkit. All baselines

Options

Option	Type	Registry value	Allowed values
BehaviorDefault: Block all prompts	Drop-down list	`fbabehavior`	Block all prompts`1` Ask the user what to do for each new host`2` Show prompts only from allowed hosts`3`
Specify hosts allowed to show form-based sign-in prompts to users	Text	`fbaenabledhosts`	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]
"fbabehavior"=dword:00000001
"fbaenabledhosts"=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: Control how Office handles form-based sign-in prompts
# Name: L_AuthenticationFBABehavior
# Scope: User
# State: Enabled
# Source: office16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common' -Name 'fbabehavior' -PropertyType 'DWord' -Value 1

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common' -Name 'fbaenabledhosts' -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_AuthenticationFBAEnabledHostsID

ADMX profile candidate (OMA-URI)

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

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: Control how Office handles form-based sign-in prompts
# Name: L_AuthenticationFBABehavior
# Scope: User
# State: Enabled
# Source: office16.admx

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common' -Name 'fbabehavior' -Kind 'DWord' -Expected 1
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\fbabehavior') | Out-Null
}

$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common' -Name 'fbaenabledhosts' -Kind 'ExpandString' -Expected ''
if (-not $isMatch) {
    $reasons.Add('Value mismatch: HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common\fbaenabledhosts') | 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: Control how Office handles form-based sign-in prompts
# Name: L_AuthenticationFBABehavior
# Scope: User
# State: Enabled
# Source: office16.admx

Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\common' -Name 'fbabehavior' -PropertyType 'DWord' -Value 1

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

History 1 retained release

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

Template

Internal name: L_AuthenticationFBABehavior
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 Area="Security Baseline" AreaCategory="Auth and Encryption" class="User" displayName="$(string.L_AuthenticationFBABehavior)" explainText="$(string.L_AuthenticationFBABehaviorExplain)" key="software\policies\microsoft\office\16.0\common" name="L_AuthenticationFBABehavior" presentation="$(presentation.L_AuthenticationFBABehavior)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="office16.Office.Microsoft.Policies.Windows:L_SecuritySettings" />
      <supportedOn ref="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
      <elements>
        <enum id="L_authenticationFBABehaviorEnum" valueName="fbabehavior">
          <item displayName="$(string.L_AuthenticationFBABehaviorBlockAllHosts)">
            <value>
              <decimal value="1" />
            </value>
          </item>
          <item displayName="$(string.L_AuthenticationFBABehaviorPromptPerHost)">
            <value>
              <decimal value="2" />
            </value>
          </item>
          <item displayName="$(string.L_AuthenticationFBABehaviorOnlyPreConfiguredHosts)">
            <value>
              <decimal value="3" />
            </value>
          </item>
        </enum>
        <text expandable="true" id="L_AuthenticationFBAEnabledHostsID" required="false" valueName="fbaenabledhosts" />
      </elements>
    </policy>

Editor controls

<presentation id="L_AuthenticationFBABehavior" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
        <dropdownList defaultItem="0" noSort="true" refId="L_authenticationFBABehaviorEnum">Behavior:</dropdownList>
        <textBox refId="L_AuthenticationFBAEnabledHostsID">
          <label>Specify hosts allowed to show form-based sign-in prompts to users:</label>
        </textBox>
        <text>If you select "Show prompts only from allowed hosts", you need to enter the hosts by name, separating the host names with a semi-colon. For example:
 
contoso.com;fabrikam.com
 
Important: You should only include hosts that you know and trust.
</text>
      </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>