> In this paper, we present NetSpectre, a generic remote Spectre variant 1 attack. For this purpose, we demonstrate the first access- driven remote Evict+Reload cache attack over network, leaking 15 bits per hour.
Exactly. 15 bits per hour, in an artificial environment with minimised noise, after untold amounts of preparatory work were already performed to analyse the software running on the target machine.
Here, have 15 bytes from a random process running on my machine (I just randomly attached a debugger, scrolled through memory arbitrarily, and copied them):
d1 e1 81 f9 fe ff 00 00 76 05 b9 fe ff 00 00 66 89
What are they? I don't know. Maybe you're really lucky and it's a key to something, or a password hash... but what? The above would've taken 8 hours to read using that attack. Now you should see the level of unconcern I have about this. Someone who is being targeted would care more, but I don't believe me and indeed the majority of users are so important as to be in such a position.
In much the same way I'm not going to install bars over every window of my house.
That's amazing, I have the same combination on my luggage!
I imagine Gmail's HTTPS certificate, or a Microsoft code signing key, or Linus' GPG key, or being able to impersonate some government agency or messaging server, are well worth 5 days of this.
The authors of that paper have the massive advantage of knowing exactly the software running on the target system and its environment; something which an attacker in the real world is unlikely to have, unless the attacker already has such familiarity with the system that it seems far easier to exfiltrate data via some other means than trying to find and setup this very slow side-channel. Everything has to be set up just right for this to work. Otherwise you might probably still manage to read something, but it's completely useless.
(High-value private keys in companies are likely to be in HSMs anyway, in which case they're completely inaccessible to attacks like these.)
Let's say you luck out and only need to read the first 100 megabytes of memory... you're talking 1000's of years.