This week, I did a piece assessing the risk of "cyberwar," and the concern about so-called “kinetic” cyber attacks - cyber attacks that would cause real-world damage. One of the people I talked to was Eireann Leverett, a security researcher at IO Active. He told me that in spite of the danger it posed, he found more than 12,000 industrial control systems, the kind of systems that control critical infrastructure, connected to the public internet. But how, exactly, did he do it?