Attackers can use a newly disclosed domain name server (DNS) vulnerability as an amplification vector in large-scale reflection-based distributed denial of service (DDoS) attacks. Attackers attempt to exploit the TsuNAME DNS vulnerability target vulnerable recursive resolvers and cause them to overwhelm authoritative DNS servers with large amounts of malicious DNS queries. The vulnerability is publically known as TsuNAME, and it can be exploited to carry out DDoS attacks against critical DNS infrastructure like large TLDs or ccTLDs.
Source: https://www.bleepingcomputer.com/news/security/new-tsuname-dns-bug-allows-attackers-to-ddos-authoritative-dns-servers/