John Gruber, reporting for DaringFireball: It's natural to speculate how a bug as egregious as the now-fixed High Sierra root login bug could escape notice for so long. It seems to have been there ever since High Sierra 10.3.0 shipped on September 25, and may have existed in the betas through the summer. One explanation is that logging in with the username "root" and a blank password is so bizarre that it's the sort of thing no one would think to try. More insidious though, is the notion that it might not have escaped notice prior to its widespread publicization yesterday -- but that the people who had heretofore discovered it kept it to themselves. This exploit was in fact posted to Apple's own support forums on November 13. It's a bizarre thread. The thread started back on June 8 when a user ran into a problem after installing the WWDC developer beta of High Sierra.