Security News > 2020 > May > New DNS Vulnerability Lets Attackers Launch Large-Scale DDoS Attacks
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Israeli cybersecurity researchers have disclosed details about a new flaw impacting DNS protocol that can be exploited to launch amplified, large-scale distributed denial-of-service attacks to takedown targeted websites.
Called NXNSAttack, the flaw hinges on the DNS delegation mechanism to force DNS resolvers to generate more DNS queries to authoritative servers of attacker's choice, potentially causing a botnet-scale disruption to online services.
The DNS infrastructure has been previously at the receiving end of a rash of DDoS attacks through the infamous Mirai botnet, including those against Dyn DNS service in 2016, crippling some of the world's biggest sites, including Twitter, Netflix, Amazon, and Spotify.
A recursive DNS lookup happens when a DNS server communicates with multiple authoritative DNS servers in a hierarchical sequence to locate an IP address associated with a domain and return it to the client.
If the first authoritative DNS name server also doesn't hold the desired records, it returns the delegation message with addresses to the next authoritative servers to which DNS resolver can query.
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