New DNS Vulnerability Lets Attackers Launch Large-Scale DDoS Attacks
May 20, 2020
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 (DDoS) 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. "We show that the number of DNS messages exchanged in a typical resolution process might be much higher in practice than what is expected in theory, mainly due to a proactive resolution of name-servers' IP addresses," the researchers said in the paper. "We show how this inefficiency becomes a bottleneck and might be used to mount a devastating attack against either or both, recursive resolvers and authoritative servers." Following responsible disclosure of NXNSAttack, several of the companies i...