A blunder during a handover of the .io registry allowed a security researcher to potentially take control of more than 270,000 .io domains.
Late Friday, Matthew Bryant noticed an unusual response to some test code he was using to map top-level domains: several of the .io authoritative name servers were available to register.
Out of interest, he tried to buy them and was
amazed to find the registration went through – leaving him potentially in control of hundreds of thousands of websites.
Full Article Here:
https://www.theregister.co.uk/2017/07/10/io_hijacking_in_transition_cockup/