Blackhole-AWS.ps1

# Add or remove?
$AddRoutes = $True
# Which interface to screw with routes on?
$InterfaceName = "Ethernet"
# Where is JSON?
$PrefixURI = "https://ip-ranges.amazonaws.com/ip-ranges.json"
# What region do we want to keep?
$RegionToKeep = "us-west-1"


# Download and convert to PSObject
$PrefixJSON = $(Invoke-WebRequest $PrefixURI | ConvertFrom-JSON).prefixes | Sort-Object -Property region

# Filter out everything we want to keep
$PrefixesToBlock = $PrefixJSON | Select ip_prefix,region -Unique | Where-Object {$_.region -NotLike $RegionToKeep}

# get ifIndex of adapter
$InterfaceIndex = $(Get-NetAdapter -Name $InterfaceName).ifIndex

if ($AddRoutes) {
    # add blackhole routes
    foreach ($Prefix in $PrefixesToBlock) {
        New-NetRoute -DestinationPrefix $Prefix.ip_prefix -NextHop 127.0.0.1 -InterfaceIndex $InterfaceIndex
    }
} else {
    # remove blackhole routes
    foreach ($Prefix in $PrefixesToBlock) {
        Remove-NetRoute -DestinationPrefix $Prefix.ip_prefix -NextHop 127.0.0.1 -InterfaceIndex $InterfaceIndex
    }
}

# show routes
Get-NetRoute -InterfaceIndex $InterfaceIndex -AddressFamily IPv4 | Out-GridView