Intel CPUs impacted by new PortSmash side-channel vulnerability
As predicted Spectre/Meltdown were just the first fruit of a major new wave of investigations into these avenues of side-channel attacks in CPUs. Now we're seeing more as it gets more attention, and it's interesting stuff. That said I think the researchers might go too far here:>"This is the main reason we released the exploit -- to show how reproducible it is," Brumley told us, "and help to kill off the SMT trend in chips.">"Security and SMT are mutually exclusive concepts," he added. "I hope our work encourages users to disable SMT in the BIOS or choose to spend their money on architectures not featuring SMT."I don't blame them for being security focused about all else at any cost and any layer, that's their gig. But I think the real response here is likely to be a lot more subtle and interesting. Of course perhaps SMT can in fact be fixed for this without a wholesale tossing in which case it'll just be a universal hardware revision somewhere down the line. This increasing level of public research and awareness of this specific class is still relatively early days after all. But taking it as a given for argument that there really is a fundamental conflict, the fact would remain that SMT can provide significant performance gains, and furthermore that we're still far from the point where SaaS/IaaS is everywhere. Lots of systems are still under single user local control, and in turn attackers being able to co-run their own arbitrary code on the same physical core isn't necessarily part of the threat model at all (and more specifically if attackers get that far least common denominator kicks in, they've already owned what's important). Even if it's desirable to run some risky code as well, hard core affinity for non-secure processes is a brute force solution in a local system context that seems like it shouldn't be a big deal given the a surfeit of physical/logical cores for many work loads.But perhaps this could be a leading edge of true processor level physical differentiation required between IaaS and more traditional deployments, and that might make for an interesting change to the competitive landscape there. It'd change the cost/benefit in some scenarios, or require more custom processor work to enact harder (and performance costing) boundaries that a traditional setup might take care of with machine isolation. I wonder if that could shift things back away from the Cloud and centralization trend in some instances, or at least create and more dynamic market?