Technology

They should name them after their investors and board members.

Sounds like Bond movies.

"whew* my horrible bubble sort implementation is safe from performance impacts

It’s not they aren’t impacted only you “don’t see the impact” as noticeably.

I was going to say, AMD had a flaw of similar severity. And they won't have a fix for a few months for most affected CPUs, and that fix will likely incur a loss in performance.

Basically it sounds like both of these flaws are due to the security chip. I can't help but feel like these flaws are by design. /tinfoil

Downfall was disclosed to Intel a year ago but was on embargo until this week. Can't help but suspect that Intel waited for AMD to be impacted by a similar event to reveal downfall

So they created a massive vulnerability by misimplementing speculative execution which promised a, what, 10% speed gain tops and now that it was discovered you have to patch it and lose 50%? Genius.

50% 💀

Dont the older chips suffer from a greater performance drop from spectre and meltdown vulnerabilities?

This inspires confidence with my 2010 ass toshiba sattelite with an i5 and 8gb DDR3. I need to look and see if mine is too old lol.

ELI5, or ELIAFYCSS (Explain like I'm a first year CS student): modern x86 CPUs have lots of optimized instructions for specific functionality. One of these is "vector instructions", where the instruction is optimized for running the same function (e.g. matrix multiply add) on lots of data (e.g. 32 rows or 512 rows). These instructions were slowly added over time, so there are multiple "sets" of vector instructions like MMX, AVX, AVX-2, AVX-512, AMX...

While the names all sound different, the way how all these vector instructions work is similar: they store internal state in hidden registers that the programmer cannot access. So to the user (application programmer or compiler designer) it looks like a simple function that does what you need without having to micromanage registers. Neat, right?

Well, problem is somewhere along the lines someone found a bug: when using instructions from the AVX-2/AVX-512 sets, if you combine it with an incorrect ordering of branch instructions (aka JX, basically the if/else of assembly) you get to see what's inside these hidden registers, including from different programs. Oops. So Charlie's "Up, Up, Down, Down, Left, Right, Left, Right, B, B, A, A" using AVX/JX allows him to see what Alice's "encrypt this zip file with this password" program is doing. Uh oh.

So, that sounds bad. But lets take a step back: how bad would this affect existing consumer devices (e.g. Non-Xeon, non-Epyc CPUs)?

Well good news: AVX-512 is not available on most Intel/AMD consumer CPUs until recently (13th gen/zen 4, and zen 4 isn't affected). So 1) your CPU most likely doesn't support it and 2) even if your CPU supports it most pre-compiled programs won't use it because the program would crash on everyone else's computer that doesn't have AVX-512. AVX-512 is a non-issue unless you're running Finite Element Analysis programs (LS-DYNA) for fun.

AVX-2 has a similar problem: while released in 2013, some low end CPUs (e.g. Intel Atom) didn't have them for a long time (this year I think?). So most compiled programs wouldn't compile with AVX-2 enabled. This means whatever game you are running now, you probably won't see a performance drop after patching since your computer/program was never using the optimized vector instructions in the first place.

So, the affect on consumer devices is minimal. But what do you need to do to ensure that your PC is secure?

Three different ideas off the top of my head:

1. BIOS update. The CPU has a some low level firmware code called microcode which is included in the BIOS. The new patched version adds additional checks to ensure no data is leaked.

2. Update the microcode package in Linux. The microcode can also be loaded from the OS. If you have an up-to-date version of Intel-microcode here this would achieve the same as (1)

3. Re-compile everything without AVX-2/AVX-512. If you're running something like Gentoo, you can simply tell GCC to not use AVX-2/AVX-512 regardless of whether your CPU supports it. As mentioned earlier the performance loss is probably going to be fine unless you're doing some serious math (FEA/AI/etc) on your machine.

You can't just search for your processor in a database I mean fuck that would take them at least an a couple hours of their precious time to set up and they have only had a year. How do you fix it?

This page tells you how to get your CPUID: https://www.intel.com/content/www/us/en/support/articles/000006831/processors/processor-utilities-and-programs.html

Then search for the CPUID here: https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html

Shared use of servers is probably the main issue

I can't comment on the general trend, but this specific one seems a bit too circumstantial to be of use for a serious spying effort. You'd have to have the spyware running parallel to the apps usong passwords you want to steal in a specific way.

The risk exists, which is bad enough for stochastic reasons (eventually, someone will get lucky and manage to grab something sensitive, and since the potential damage from that is incalculable, the impact axis alone drives this into firm "you need to get that fix out asap), but probably irrelevant in terms of consistency, which would be what you'd need to actually monitor anyone.

If you manage to grab enough info to crack some financial access data, you can steal money. If you can take over some legit online account or obtain some email-password combo, you can sell it. But if you want to monitor what people are doing in otherwise private systems, you need some way to either check on demand or log their actions and periodically send them to your server.

It would be far more reliable to have injection backdoors to allow you access by virtue of forcing a credential check to come up valid than to hope for the lucky grab of credentials the user might change at an arbitrary moment in time.

Isn't that convenient?

Oh don't worry, you'll hear about that vulnerability in two years.

If it's anything like the industry that I work in, the CEO would have been informed of the short comings of the design numerous times and given a response along the lines of "does it make our CPUs faster and more powerful though?".

The CEO won't be pissed of at his chip designer, they'll be pissed because they've been caught out.