According to new research, more than 80 percent of public DNS servers around the world are open to pharming and DoS attacks. It has been found that 84 percent of authoritative DNS servers connected to the internet allowed recursive name services to arbitrary queries.
Best practices in the industry dictate that recursive name services - a form of name resolution that requires a name server to relay requests to other name servers - should only be enabled on a DNS server for a restricted list of known, trusted requesters. Providing recursion to arbitrary IP addresses on the internet exposes a name server to both cache poisoning and denial of service attacks.
Cache poisoning or "pharming" allows a hacker to redirect traffic away from a real website to a fake one set up by the hacker. From there the hacker then steals a user's account information.
Cricket Liu, vice president of architecture at Infoblox, who had the study done by internet testing company The Measurement Factory, called the results frightening.