You can create an account on Linode, but you will need to put a credit card on file. Once set up you can create a zone here. If the domain is available the zone will be created, but not begin serving just yet. You need a paid "Linode" running (which is one of their servers instance) for the zone to begin serving. The cheapest server is $5 per month. Once activated the zone will start serving records and the takeover will be successful.
Service
LinodeStatus
VulnerableNameserver
Explanation
You can create an account on Linode, but you will need to put a credit card on file. Once set up you can create a zone here. If the domain is available the zone will be created, but not begin serving just yet. You need a paid "Linode" running (which is one of their servers instance) for the zone to begin serving. The cheapest server is $5 per month. Once activated the zone will start serving records and the takeover will be successful.