Do they mean "only confirmed on Zen2", or is the problem definitely confined to only this architecture?

Is it likely that this same technique (or similar) also works on earlier (Zen/Zen+) or later (Zen3) cores, but they just haven't been able to demonstrate it yet?

It's Tavis Ormandy, and he reported it to AMD, so one would assume they tried it on related hardware and it's not working.

I tested on a Zen 3 Epyc and wasn't able to get the POC to work, so I think it probably is just Zen 2.

At least the stock exploit code he provided said "nope I can't get shit to leak" on my 5900X.

Doesn't repro on 2920x (Zen+).

Looks like my 2700x narrowly misses this one, assuming 7020 series is affected and not 7000 series.

Yeah -- Ryzen 2700x is Zen+, not Zen 2. Current understanding is that Zen+ is not affected.

The wording "at least" suggests the list might not be exhaustive.

and how about playstation 5 ?

and also xbox and that thing from valve?

I mean, the PS5 is running a Zen 2 processor [0] so I would assume it's vulnerable. In general I would assume that AAA games are safe. Websites and smaller games made by malefactors will be the issue. (Note that AAA game makers have little interest in antagonizing the audience, OTOH they also will push limits to install anti-cheat mechanisms. On balance I'd trust them.)

0 - https://blog.playstation.com/2020/03/18/unveiling-new-detail...

I think the interesting point here might be one could be able to extract some secret from memory of a PS5, like to break some kind of encryption

Interresting, could well be a path to jailbreaking the PS5... although, not sure if that has or hasn't already happened. For XBox Series, you can just use dev mode in the first place.

What valuable secrets do people have on their PS5/Xbox? You also need a way to deploy the malicious payload on those platforms which, due to their closed nature, is very difficult to do.

The valuable secret here would be the keys that let you decrypt and copy games. The threat models of locked-down platforms are incredibly strange.

That's a good point but I can't believe that every console doesn't have it's own unique set of keys so that if you compromise one before SW patches land, it won't be much use in the ecosystem.

It depends. I'm going to speak in general terms, since I obviously don't know how every single system works, but per-console keys are used for pairing system storage to the motherboard and maybe keeping save data from being copied from user to user. Most CDNs don't really provide the option for on-the-fly per user encryption, so instead you serve up games encrypted with title keys and then issue each console a title key that's encrypted with a per-console key. Disc games need to be encrypted with keys that every system already has, otherwise you can't actually use the disc to play the game.

As for the value of being able to do 'hero attacks' on game consoles, let me point out that once you have a cleartext dump of a game, you've already done most of the work. The Xbox 360 was actually very well secured, to the point where it was easier to hack a disc drive to inject fake authentication data into a normal DVD-R than to actually hack a 360's CPU to run copied games. That's why we didn't have widely-accessible homebrew on that platform for the longest time. Furthermore, you can make emulators that just don't care about authenticating media (because why would they) and run cleartext games on those.

At least with the PS3, I seem to recall that I couldn't extract any of my games' save data from the hard-drive of my PS3 unit that went dead due to RROD (or was it YLOD?) because the hard-drive was encrypted using the PS3's serial key as part of the encryption.

I don't know if that mechanism persists into the PS4/PS5.

Oh, I can imagine lots of uses for a bevy of PS5's, assuming you can gain remote control. What do you do with a botnet? What do you do with a botnet with a pretty good GPU? What do you do with an always-on microphone in people's living rooms?

So are Ryzen 5000's without Radeon not vulnerable? I guess said processors are zen 3?

I have an "AMD Ryzen 9 5950x Desktop Processor" which appears to be Zen 3. I think I'm good?

(Not that I'm running untrusted workloads, but yknow, fortune favors the prepared)

You are likely frequently running untrusted workloads. As javascript in a browser. I don't know about this one, but at least meltdown was fully exploitable from js.

But yes, you are fine, 5950x is Zen3.

I was under the impression that 5600g and 5600u were Zen3, but being the APU models they have Radeon graphics.

Anecdotally, I tried to reproduce on my 5600g but couldn't. Which is surprising because they claim it works on 5700u...

Edit: just discovered that while my 5600g is Zen3, the 5700u is Zen2. Lol.

Your point is valid, but the processor in question is a server, so actually no js being run :).

I wish Firefox would use PR_SCHED_CORE to reduce the likelihood of such leakage...

The idea being that the main process and content processes should never be on the same core?

I would worry about cross site leakage. From my understanding that would be unavoidable as soon as you have more tabs open than cores, which feels like an unworkable restriction.

Imagine opening a 9th tab and bring told you need to upgrade your 3700X to a 3900X.

I think there's several levels. As a first step, I'd appreciate reducing the risk of javascript extracting contents from outside the browser. A second step could be to use more granular core scheduling within firefox, to prevent sharing cores that shouldn't be shared. A process/thread hierarchy can create multiple core scheduling groups.

>As a first step, I'd appreciate reducing the risk of javascript extracting contents from outside the browser.

But that means essentially reserving a core for the browser only. I don't think that would be shippable by default.

FYI, Ryzen 3000 APUs aren't Zen 2.

> AMD Ryzen 3000 Series Processors

The above are desktop. If they meant APUs, it would list "Ryzen 3000 Series Processors with Radeon Graphics."

They are Zen+, aren't they?

Whew, my 5600X looks like it avoided this one too. :)