I wonder which, if any, government organizaations knew about this. Did the DoD know? Russia? China? I remember reading about a "cyperweapon" the US government

I wonder which, if any, government organizaations knew about this. Did the DoD know? Russia? China? I remember reading about a "cyperweapon" the US government was using to cause North Korean missile tests to fail before launch. Could attacks like this be possible through meltdown?