Microsoft Excel 2016 › Excel Options › Security › Trust Center › External Content
Don’t allow Dynamic Data Exchange (DDE) server launch in Excel
Supported on SUPPORTED_Windows7 (defined in the Windows templates)
What it does
This policy setting allows you to control whether Dynamic Data Exchange (DDE) server launch is allowed. By default, DDE server launch is turned off, but users can turn on DDE server launch by going to File > Options > Trust Center > Trust Center Settings > External Content. For security reasons, turning on DDE server launch is not recommended. Note: For DDE server launch to work, Dynamic Data Exchange (DDE) server lookup must be turned on. Be sure that the “Don’t allow Dynamic Data Exchange (DDE) server lookup” policy setting isn’t enabled, because enabling that policy setting turns off DDE server lookup. If you enable this policy setting, DDE server launch isn’t allowed, and users can’t turn on DDE server launch in the Trust Center. If you disable this policy setting, DDE server launch is allowed, and users cannot turn off DDE server launch in the Trust Center. For security reasons, this is not recommended. If you don’t configure this policy setting, DDE server launch is turned off, but users can turn on DDE server launch in the Trust Center. Note: This policy setting only applies to subscription versions of Office, such as Microsoft 365 Apps for enterprise.
What it writes
- Hive
- HKEY_CURRENT_USER
- Registry key
software\policies\microsoft\office\16.0\excel\security\external content- Value name
disableddeserverlaunch- When enabled
- DWORD 1
- When disabled
- DWORD 0
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 - DDE Block - User”.
- Policy value disableddeserverlaunch
- Sets disableddeserverlaunch to 1 (REG_DWORD).
Read from the registry.pol files in the baselines' GPO backups, downloaded from Microsoft's Security Compliance Toolkit. All baselines
Configure and deploy
Choose a state; 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\excel\security\external content]
"disableddeserverlaunch"=dword:00000001
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: Don’t allow Dynamic Data Exchange (DDE) server launch in Excel
# Name: L_DisableDDEServerLaunch
# Scope: User
# State: Enabled
# Source: excel16.admx
Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\excel\security\external content' -Name 'disableddeserverlaunch' -PropertyType 'DWord' -Value 1
- 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.
ADMX profile candidate (OMA-URI)
./User/Vendor/MSFT/Policy/Config/ADMX_excel16/L_DisableDDEServerLaunchADMX SyncML candidate
<SyncML xmlns="SYNCML:SYNCML1.2">
<SyncBody>
<Replace>
<CmdID>1</CmdID>
<Item>
<Meta>
<Format>chr</Format>
<Type>text/plain</Type>
</Meta>
<Target>
<LocURI>./User/Vendor/MSFT/Policy/Config/ADMX_excel16/L_DisableDDEServerLaunch</LocURI>
</Target>
<Data><enabled/></Data>
</Item>
</Replace>
<Final/>
</SyncBody>
</SyncML>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: Don’t allow Dynamic Data Exchange (DDE) server launch in Excel
# Name: L_DisableDDEServerLaunch
# Scope: User
# State: Enabled
# Source: excel16.admx
$isMatch = Test-RegistryValueEquals -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\excel\security\external content' -Name 'disableddeserverlaunch' -Kind 'DWord' -Expected 1
if (-not $isMatch) {
$reasons.Add('Value mismatch: HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\excel\security\external content\disableddeserverlaunch') | Out-Null
}
if ($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 $propertyName -Force -ErrorAction SilentlyContinue
}
}
# Policy: Don’t allow Dynamic Data Exchange (DDE) server launch in Excel
# Name: L_DisableDDEServerLaunch
# Scope: User
# State: Enabled
# Source: excel16.admx
Set-RegistryValue -Path 'Registry::HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\excel\security\external content' -Name 'disableddeserverlaunch' -PropertyType 'DWord' -Value 1
History 1 retained release
- 5568.100010 Aug 2026
- Already present in the first release ChangeIntel keeps.
Template
- Internal name
L_DisableDDEServerLaunch- Namespace
excel16.Office.Microsoft.Policies.Windows- Template file
excel16.admx- Release
- Microsoft 365 Apps 5568.1000 · file set
8be05d876aae137d…
Definition, editor controls and support
Definition
<policy Area="Security Baseline" AreaCategory="DDE" class="User" displayName="$(string.L_DisableDDEServerLaunch)" explainText="$(string.L_DisableDDEServerLaunchExplain)" key="software\policies\microsoft\office\16.0\excel\security\external content" name="L_DisableDDEServerLaunch" valueName="disableddeserverlaunch" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_ExternalContent" />
<supportedOn ref="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
<enabledValue>
<decimal value="1" />
</enabledValue>
<disabledValue>
<decimal value="0" />
</disabledValue>
</policy>Editor controls
Supported platforms and category
excel16.Office.Microsoft.Policies.Windows:category:L_ExcelOptions
<category displayName="$(string.L_ExcelOptions)" name="L_ExcelOptions" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeExcel" />
</category>
excel16.Office.Microsoft.Policies.Windows:category:L_ExternalContent
<category displayName="$(string.L_ExternalContent)" name="L_ExternalContent" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_TrustCenter" />
</category>
excel16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeExcel
<category displayName="$(string.L_MicrosoftOfficeExcel)" name="L_MicrosoftOfficeExcel" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
excel16.Office.Microsoft.Policies.Windows:category:L_Security
<category displayName="$(string.L_Security)" name="L_Security" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_ExcelOptions" />
</category>
excel16.Office.Microsoft.Policies.Windows:category:L_TrustCenter
<category displayName="$(string.L_TrustCenter)" name="L_TrustCenter" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_Security" />
</category>
excel16.Office.Microsoft.Policies.Windows:unresolved:Microsoft.Policies.Windows:SUPPORTED_Windows7
<unresolved reference="Microsoft.Policies.Windows:SUPPORTED_Windows7" />
excel16.Office.Microsoft.Policies.Windows:category:L_ExcelOptions
<category displayName="$(string.L_ExcelOptions)" name="L_ExcelOptions" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeExcel" />
</category>
<strings><string id="excel16.Office.Microsoft.Policies.Windows:L_ExcelOptions">Excel Options</string></strings>
excel16.Office.Microsoft.Policies.Windows:category:L_ExternalContent
<category displayName="$(string.L_ExternalContent)" name="L_ExternalContent" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_TrustCenter" />
</category>
<strings><string id="excel16.Office.Microsoft.Policies.Windows:L_ExternalContent">External Content</string></strings>
excel16.Office.Microsoft.Policies.Windows:category:L_MicrosoftOfficeExcel
<category displayName="$(string.L_MicrosoftOfficeExcel)" name="L_MicrosoftOfficeExcel" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="excel16.Office.Microsoft.Policies.Windows:L_MicrosoftOfficeExcel">Microsoft Excel 2016</string></strings>
excel16.Office.Microsoft.Policies.Windows:category:L_Security
<category displayName="$(string.L_Security)" name="L_Security" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_ExcelOptions" />
</category>
<strings><string id="excel16.Office.Microsoft.Policies.Windows:L_Security">Security</string></strings>
excel16.Office.Microsoft.Policies.Windows:category:L_TrustCenter
<category displayName="$(string.L_TrustCenter)" name="L_TrustCenter" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="excel16.Office.Microsoft.Policies.Windows:L_Security" />
</category>
<strings><string id="excel16.Office.Microsoft.Policies.Windows:L_TrustCenter">Trust Center</string></strings>