Jay Freeman, who goes by Saurik, is a security consultant who's best known as the father of Cydia, a sort of alternate app store for jailbroken iPhones. If you want to overclock your iPhone, use it as a wireless hotspot without paying your carrier extra, or play Super Nintendo games on it, Cydia is for you. Freeman's Glass hack requires that the Glass be put in "debug" mode, but that doesn't take much. According to Ars Technica, which has a great piece on the subject, Freeman can pick up the Glass hardware and set it in this mode without the user ever knowing. And it doesn't take much to then get unfettered access to everything on that user's Glass; says Freeman, "This exploit is simple enough that you can pull it off with just a couple files, and without any specialized tooling."