GovInfoSecurity Compliance Compliance Twitter Get Permission Security researchers have uncovered a flaw dubbed TsuNAME in DNS resolver software that can be used to carry out distributed denial-of-service attacks against authoritative DNS servers. Google and Cisco have resolved the issue in their DNS servers. Authoritative DNS servers are the final holder of the IP of a domain, responsible for providing details about specific websites to DNS servers, including information on domain names and IP addresses. The security researchers, Giovane C. M. Moura, Sebastian Castro, John Heinemann and Wes Hardaker, note the flaw affects DNS resolvers, which play a key role in converting web links to IP addresses in authoritative DNS servers.