The Internet began to wobble at 7 a.m. Early on Oct. 21, servers at a little-known Internet infrastructure company, Dyn, based in Manchester, N.H., began experiencing an overwhelming flood of malicious traffic. By midday a coordinated series of attacks had metastasized, eventually blocking or significantly slowing access to dozens of sites, including Twitter, Netflix, Spotify and Airbnb, for millions of Americans as well as web users in Brazil, Germany, India, Spain and the U.K. The FBI and the Department of Homeland Security are looking into the attack, thought to be the largest of its kind ever. But by the time the disturbance ebbed the following day, the point security researchers have been making to one another at an increasingly alarmed pitch in recent months became clear to a much broader…
