The purpose of DNS tunneling attack
DNS tunneling is a sort of Domain Name System attack, as the name implies. It employs a client-server mechanism to push malware across a tunnel. In addition, it is a black hat approach for establishing a covert conduit into a victim’s machine or network.
The channel constructed allows embedding a malicious payload within DNS queries, allowing attackers to take advantage of DNS traffic’s largely unconstrained flow—especially in settings where practically all other communication is controlled.