https://tsuname.io/

May 6th, 2021: Today, researchers at SIDN Labs, (.nl registry), InternetNZ(.nz registry) , and at the Information Science Institute at the University of Southern California publicly disclose tsuNAME, a vulnerability in DNS resolver software that can be weaponized to carry out DDoS attacks against authoritative DNS servers.

Security Advisory : https://tsuname.io/advisory.pdf
Tech Report : https://tsuname.io/tech_report.pdf
CycleHunter : Open-source tool to detect cyclic dependencies in DNS zone files : https://github.com/SIDN/CycleHunter