Last week Bloomberg Businessweek published an article named The Big Hack. The authors claim that testers have found a tiny microchip on server mainboards that wasn’t part of the original designs: During the ensuing top-secret probe, which remains open more than three years later, investigators determined that the chips allowed the attackers to create a stealth doorway into any network that included the altered machines. Multiple people familiar with the matter say investigators found that the chips had been inserted at...