https://github.com/pwnesia/dnstake
1. whois
DNSTake A fast tool to check missing hosted DNS zones that can lead to subdomain takeover. What is a DNS takeover? DNS takeover vulnerabilities occur when a subdomain (subdomain.example.com) or domain has its authoritative nameserver set to a provider (e.g. AWS Route 53, Akamai, Microsoft Azure, etc.) but the hosted zone has been removed or deleted. Consequently, when making a request for DNS records the server responds with a SERVFAIL error. This allows an attacker to create the missing hosted zone on the service that was being used and thus control all DNS records for that (sub)domain.