No, that's not a working exploit, as is said in the paper: > Chrome intentionally degrades the accuracy of its high-resolution timer to dissuade timing attacks

No, that's not a working exploit, as is said in the paper: > Chrome intentionally degrades the accuracy of its high-resolution timer to dissuade timing attacks using performance.now() [62]. However, the Web Workers feature of HTML5 makes it simple to create a separate thread that repeatedly decrements a value in a shared memory location [24, 60]. This approach yields a high-resolution timer that provides sufficient resolution. They did it on Chrome 62.0.3202, but SharedArrayBuffer was disabled in all major browsers right when spectre dropped. Chrome enabled it again in Chrome 67 if Full Site Isolation was enabled. Full site isolation is now enabled by default afaik. So no, that is in no way a working exploit in any major browser I know of. There is no know spectre (or other variant) exploit that works in a default updated major browser (and there has never been as far as I know), but feel free to link any PoC's.