Implement strict extension controls to prevent malicious extensions from exploiting browser vulnerabilities. This is critical since extensions can bypass many browser security features.
# Create Chrome policy JSON for extension management
# Save as: C:\Program Files\Google\Chrome\Application\master_preferences
{
"homepage": "https://intranet.company.com",
"homepage_is_newtabpage": false,
"browser": {
"show_home_button": true
},
"bookmark_bar": {
"show_on_all_tabs": true
},
"distribution": {
"skip_first_run_ui": true,
"show_welcome_page": false,
"import_search_engine": false,
"import_history": false,
"import_bookmarks": false,
"import_home_page": false,
"do_not_create_any_shortcuts": true,
"do_not_create_desktop_shortcut": true,
"do_not_create_quick_launch_shortcut": true,
"do_not_create_taskbar_shortcut": true
},
"extensions": {
"settings": {
"cjpalhdlnbpafiamejdnhcphjbkeiagm": {
"location": 1,
"manifest": {
"name": "uBlock Origin",
"permissions": ["activeTab", "storage"]
}
},
"nngceckbapebfimnlniiiahkandclblb": {
"location": 1,
"manifest": {
"name": "Bitwarden",
"permissions": ["activeTab", "storage"]
}
}
}
}
}
Create a comprehensive extension allowlist using Group Policy:
# PowerShell script to configure extension allowlist via registry
$allowedExtensions = @(
"cjpalhdlnbpafiamejdnhcphjbkeiagm", # uBlock Origin
"nngceckbapebfimnlniiiahkandclblb", # Bitwarden
"gighmmpiobklfepjocnamgkkbiglidom", # AdBlock
"fhbjgbiflinjbdggehcddcbncdddomop" # Postman Interceptor
)
# Registry path for Chrome policies
$chromePolicyPath = "HKLM:\SOFTWARE\Policies\Google\Chrome"
$extensionPath = "$chromePolicyPath\ExtensionInstallAllowlist"
# Create registry structure
if (!(Test-Path $chromePolicyPath)) {
New-Item -Path $chromePolicyPath -Force
}
if (!(Test-Path $extensionPath)) {
New-Item -Path $extensionPath -Force
}
# Set extension blocklist (block all by default)
Set-ItemProperty -Path $chromePolicyPath -Name "ExtensionInstallBlocklist" -Value "*" -Type String
# Add allowed extensions
for ($i = 0; $i -lt $allowedExtensions.Count; $i++) {
Set-ItemProperty -Path $extensionPath -Name ($i + 1) -Value $allowedExtensions[$i] -Type String
}
# Additional security settings
Set-ItemProperty -Path $chromePolicyPath -Name "DeveloperToolsAvailability" -Value 2 -Type DWord # Disable dev tools
Set-ItemProperty -Path $chromePolicyPath -Name "ExtensionInstallForcelist" -Value "" -Type String
Set-ItemProperty -Path $chromePolicyPath -Name "SafeBrowsingProtectionLevel" -Value 2 -Type DWord # Enhanced protection
Write-Host "Chrome extension policies configured successfully" -ForegroundColor Green
Implement extension monitoring and compliance checking:
# Extension compliance monitoring script
function Get-ChromeExtensionCompliance {
param([string[]]$ComputerNames)
$results = @()
foreach ($computer in $ComputerNames) {
if (Test-Connection -ComputerName $computer -Count 1 -Quiet) {
$extensionData = Invoke-Command -ComputerName $computer -ScriptBlock {
$userProfiles = Get-ChildItem "C:\Users" -Directory | Where-Object { $_.Name -notmatch "^(Public|Default|All Users)$" }
$extensions = @()
foreach ($profile in $userProfiles) {
$extensionPath = "$($profile.FullName)\AppData\Local\Google\Chrome\User Data\Default\Extensions"
if (Test-Path $extensionPath) {
$installedExtensions = Get-ChildItem $extensionPath -Directory
foreach ($ext in $installedExtensions) {
$extensions += @{
User = $profile.Name
ExtensionID = $ext.Name
Path = $ext.FullName
}
}
}
}
return $extensions
}
$results += [PSCustomObject]@{
Computer = $computer
Extensions = $extensionData
ComplianceStatus = "Needs Review"
}
}
}
return $results
}
# Run compliance check
$complianceResults = Get-ChromeExtensionCompliance -ComputerNames (Get-ADComputer -Filter * | Select-Object -First 10 -ExpandProperty Name)
$complianceResults | Export-Csv -Path "C:\ChromeExtensionCompliance-$(Get-Date -Format 'yyyyMMdd').csv" -NoTypeInformation
Pro tip: Regularly audit your extension allowlist. Remove extensions that are no longer needed and monitor for new security vulnerabilities in approved extensions.
Verification: Navigate to chrome://extensions on test machines to confirm only allowlisted extensions are installed and enabled.
