Schneier on Spectre and Meltdown:
The security of pretty much every computer on the planet has just gotten a lot worse, and the only real solution – which of course is not a solution – is to throw them all away and buy new ones.
"Throw it away and buy a new one" is ridiculous security advice, but it's what US-CERT recommends. It is also unworkable. The problem is that there isn't anything to buy that isn't vulnerable. Pretty much every major processor made in the past 20 years is vulnerable to some flavor of these vulnerabilities. Patching against Meltdown can degrade performance by almost a third. And there's no patch for Spectre; the microprocessors have to be redesigned to prevent the attack, and that will take years. (Here's a running list of who's patched what.)
This is bad, but expect it more and more. Several trends are converging in a way that makes our current system of patching security vulnerabilities harder to implement.
Spectre and Meltdown are pretty catastrophic vulnerabilities, but they only affect the confidentiality of data. Now that they – and the research into the Intel ME vulnerability – have shown researchers where to look, more is coming – and what they'll find will be worse than either Spectre or Meltdown. There will be vulnerabilities that will allow attackers to manipulate or delete data across processes, potentially fatal in the computers controlling our cars or implanted medical devices. These will be similarly impossible to fix, and the only strategy will be to throw our devices away and buy new ones.
Schneier is rarely optimistic when it comes to security issues. But I'd never bet against him being right, either.