DNSChanger is a piece of malware that was used in a large click-fraud campaign known as Ghost Click. The FBI helped take down the DNSChanger crew last year and at the time of the bust, estimated that there were several million PCs infected with the malware. When the FBI took down the gang behind this attack, it also took control of the rogue DNS servers and continued to operate them so that all of the infected users could still access the Internet. No one owns the DNS system, it s a network of millions of servers around the world that do the heavy lifting of name lookups.
Source: https://threatpost.com/dnschanger-faq-internet-not-broken-070912/76778/