Security researchers disclose a new critical vulnerability affecting Domain Name System (DNS) resolvers. The flaw, called ‘TsuNAME,’ was discovered by researchers from SIDN Labs and InternetNZ. It could be exploited by adversaries to carry out reflection-based denial-of-service attacks against authoritative nameservers. Google Public DNS (GDNS) and Cisco OpenDNS have since addressed the issue in their DNS resolver software. To mitigate the impact of TsuNAME in the wild, the researchers have published an open-source tool called CycleHunter.
Source: https://thehackernews.com/2021/05/new-tsuname-flaw-could-let-attackers.html