Domain Name System (DNS) is the ‘phone book of the internet, converting the domain names humans type into the IP addresses machines need to communicate online. The DNS was designed and built decades ago, long before commercial cybercrime, with usability rather than security in mind. Complex web of inter-linked servers run by ISPs, telecoms companies and some large corporates means a potentially huge attack surface for hackers to target. There are three main types of DNS-based attacks: amplification, poisoning, bypassing and bypass.
Source: https://www.infosecurity-magazine.com/magazine-features/whats-the-deal-with-dns/