Allowed Sites
Verified with Mozilla Firefox v8.2 — updated on July 10, 2026
Supported on: Firefox 60 or later, Firefox 60 ESR or later
Path in the GPO console
Computer Configuration\Administrative Templates\Mozilla\Firefox\Addons User Configuration\Administrative Templates\Mozilla\Firefox\Addons Description
If this policy is enabled, add-ons are always allowed for the origins indicated unless add-on install is disabled. If a top level domain is specified (http://example.org), add-ons are allowed for all subdomains as well. If this policy is disabled or not configured, the default add-on policy is followed.
Registry
HKLM
Software\Policies\Mozilla\Firefox HKCU
Software\Policies\Mozilla\Firefox Export Builder
BETAConfigure the state, scope and options, then generate .reg, PowerShell, Intune and SCCM outputs — or add the setting to a multi-setting collection.
These exports write the registry — this is not a managed GPO. ⓘ
Applying both scopes creates an ambiguous configuration (computer takes precedence over user). Only do this intentionally.
.reg file
Windows Registry Editor Version 5.00
; Exported from gporais.com
; Policy: Allowed Sites
; State: Enabled
; Scope: Computer (HKLM)
; Supported on: Firefox 60 or later, Firefox 60 ESR or later
[HKEY_LOCAL_MACHINE\Software\Policies\Mozilla\Firefox\InstallAddonsPermission\Allow]
; List values: enter one value per line in the builder UI.More formats (PowerShell, Intune, SCCM)
PowerShell
# Exported from gporais.com
# Policy: Allowed Sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 60 or later, Firefox 60 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\InstallAddonsPermission\Allow'
New-Item -Path $path -Force | Out-Null
# List values: enter one value per line in the builder UI.Intune XML
No direct Policy CSP / OMA-URI mapping for this policy. Use the Intune Remediation tab, or ingest the ADMX in Intune.Intune Remediation
# === Detection script ===
# Exported from gporais.com
# Policy: Allowed Sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 60 or later, Firefox 60 ESR or later
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
# HKLM:\Software\Policies\Mozilla\Firefox\InstallAddonsPermission\Allow: List values: enter one value per line in the builder UI.
# No testable registry values are available for this state.
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Allowed Sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 60 or later, Firefox 60 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\InstallAddonsPermission\Allow'
New-Item -Path $path -Force | Out-Null
# List values: enter one value per line in the builder UI.SCCM scripts
# Exported from gporais.com
# Policy: Allowed Sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 60 or later, Firefox 60 ESR or later
# SCCM Configuration Item guidance:
# Create a Configuration Item of type "Setting: Script".
# Discovery script: use the Detection script below.
# Remediation script: use the Remediation script below.
# Compliance rule: the Discovery script output equals 'Compliant'.
# === Detection script ===
# Exported from gporais.com
# Policy: Allowed Sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 60 or later, Firefox 60 ESR or later
function Test-RegistryValue {
param(
[Parameter(Mandatory = $true)][string]$Path,
[Parameter(Mandatory = $true)][string]$Name,
[object]$Expected,
[ValidateSet('String', 'DWord', 'MultiString')][string]$Kind = 'String',
[switch]$Absent
)
try {
$item = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction Stop
} catch {
return $Absent.IsPresent
}
if ($Absent.IsPresent) { return $false }
$actual = $item.$Name
if ($Kind -eq 'DWord') { return ([int64]$actual) -eq ([int64]$Expected) }
if ($Kind -eq 'MultiString') {
$actualValues = @($actual)
$expectedValues = @($Expected)
if ($actualValues.Count -ne $expectedValues.Count) { return $false }
for ($i = 0; $i -lt $expectedValues.Count; $i++) {
if ([string]$actualValues[$i] -ne [string]$expectedValues[$i]) { return $false }
}
return $true
}
return [string]$actual -eq [string]$Expected
}
# HKLM:\Software\Policies\Mozilla\Firefox\InstallAddonsPermission\Allow: List values: enter one value per line in the builder UI.
# No testable registry values are available for this state.
Write-Output 'Non-compliant'
exit 1
# === Remediation script ===
# Exported from gporais.com
# Policy: Allowed Sites
# State: Enabled
# Scope: Computer (HKLM)
# Supported on: Firefox 60 or later, Firefox 60 ESR or later
$path = 'HKLM:\Software\Policies\Mozilla\Firefox\InstallAddonsPermission\Allow'
New-Item -Path $path -Force | Out-Null
# List values: enter one value per line in the builder UI.Building a multi-setting collection? Add this setting and generate combined .reg / PowerShell / GPO scripts.