1. You design your CPU so whenever you execute an add instruction with $r1 = x, $r2 = y (say these are the add inputs), the next add instruction will switch to ring-0 mode and run code at address which is the result of the add.
2. You don't need access to the box. You just get the target to load a site with JS that sets x and y to those specfic values and adds them, and then adds zero to some address you want to execute (which you can aim to be shellcode in a JS string or something, but even if not there are a million tricks you can use to execute arbitrary code if you can run code at an arbitrary address).
3. Assuming the JS engine compiles sanely, you now have a way to control any computer and make it do anything via some JS on any web site. Ring-0 can totally bypass all virtualization and even the OS itself.
And this exploit is so simple and powerful that everything else is a waste of time. No need to use statistical and entropy tricks to leak keys. You can own any computer with JS on a web site and steal anything you want from memory, including keys. And you can probably do this without the target noticing anything.
2. You don't need access to the box. You just get the target to load a site with JS that sets x and y to those specfic values and adds them, and then adds zero to some address you want to execute (which you can aim to be shellcode in a JS string or something, but even if not there are a million tricks you can use to execute arbitrary code if you can run code at an arbitrary address).
3. Assuming the JS engine compiles sanely, you now have a way to control any computer and make it do anything via some JS on any web site. Ring-0 can totally bypass all virtualization and even the OS itself.
And this exploit is so simple and powerful that everything else is a waste of time. No need to use statistical and entropy tricks to leak keys. You can own any computer with JS on a web site and steal anything you want from memory, including keys. And you can probably do this without the target noticing anything.