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I cannot wait for the accompanying Black Hat talk. Christopher Domas is one of my absolute favorite all-time hackers. He does such a fantastic job of explaining his work. Some of my favorite talks of his:

- Psychological Warfare in Reverse Engineering https://www.youtube.com/watch?v=HlUe0TUHOIc

- The MoVfuscator https://www.youtube.com/watch?v=R7EEoWg6Ekk

- Hardware Backdoors in redacted x86 https://www.youtube.com/watch?v=jmTwlEh8L7g

My introduction to his work was "The future of RE Dynamic Binary Visualization"[0] which completely blew me away. It still feels futuristic today, 13 years later. Novel UI/UX paradigms like this are slow to find widespread adoption, even when they're so clearly demonstrated to be such an ideal fit for their purpose.

0: https://www.youtube.com/watch?v=4bM3Gut1hIk&pp=ygURY2hyaXN0b...

If this is the same dude I am thinking of, his wife is also the CISO of Mozilla and do security research together, afair they have a whole book on x86 reverse engineering.

Very cool!

> He does such a fantastic job of explaining his work.

He did a fantastic job of explaining his work.

I saw a recent video and I was shocked that he had hair:

https://www.youtube.com/watch?v=iOq8O_phwbA

He looks so different.

His stuff is something else.
Alright, a new series to binge now.
When I started with computers, DRAM was understandable by a teenager: RAS, CAS, read, done.

Ok, the necessary refresh was always a little pain, but still something manageable.

Nowadays, I feel you need three PhD's to even bring up a micro with DRAM and don't get me started on the proprietary binary blobs necessary just for DRAM access. No wonder PSRAM is a thing.

The corollary is that it shouldn't be too surprising that this gigantic attack surface provides many opportunities. (Of course that doesn't mean it is easy to find them, hat tip to Christopher Domas, just that I expect there to be many more).

So true. The levels of indirection from a pointer to an actual DRAM chip address are insane.

Then there's the electrical bus: DDR5 runs so fast it need channel characterisation (sorta like the old model dial up sounds) on the lines between the controller and the DRAM. No more 5V and 0V for TTL signals there.

This is all great to get full unfettered access to your own system, as life should be.

I’m sure Xbox and PlayStation security groups are a little nervous right now though. Getting ring-0 on those machines is near impossible, but once you do then everything else becomes wide open

Not sure if it opens up that much on them as far as their security processors go. Modern consoles already treat DRAM as completely untrusted (an attacker could just sit on the DRAM bus and sniff/issue requests there).

The Xbox One for example encrypts all the DRAM it uses after it gets out of the main CPU die. See this part of Tony Chen's presentation https://youtu.be/U7VwtOrwceo?t=956

Also see this bit on the Apple Secure Enclave in the "Memory Protection Engine" section which also explains how they encrypt stuff stored in DRAM: https://support.apple.com/guide/security/the-secure-enclave-...

Xbox One runs everything under HyperV, so any user created code likely doesn't have the hardware access to use this exploit.
Seems like this should get us a newer PS4 jailbreak?
OK, so this works on AMD Jaguar according to the README. That's a architecture from 2013. There's notes about Zen 3 having a different base address for the memory controller registers, but that's it. What newer CPUs does attack actually work on?
CPU designers have been aware of this attack vector for a while, so many (maybe all) have controls to lock these registers. They are written and locked by vendor firmware before it hands off to the operating system.

You would have first break the firmware or locks before an attack like this on a modern CPU

So on an affected system, ring 0 root has access to pretty much everything that was hidden in negative ring territory. The page is pretty quiet about what other processor families might be similar beyond this specific AMD16h (an older AMD low-power family)?
This is only applicable if you already have root (in order to get beyond that), right? It doesn't expose new risk of local privilege escalation?
The researcher behind this is obviously highly knowledgeable in reverse engineering CPUs to the tune it reminds me of the dwarves digging in Moria...

But why on earth do they have to use AI to write their writeups?!

I really hate to be that guy, but man, as someone who was and is a big Christopher Domas fan (and is way dumber than him, I mean, this stuff is seriously over my head)... it's been really disappointing to see him LLM'ing all the READMEs recently. They used to be a joy to read through, but now the Claudeisms made it such a slog I could barely get through a few paragraphs. I'm glad he's using the new tools to get even more cool stuff done, but I wish he'd have gone for a human writeup at the end.
Im confused seeing all the negative 'he used AI in writeups'. This guy released 5 new open source projects last week, including white papers and gave 3 unique talks (2 blackhat, 1 defcon). NONE of those conferences require whitepapers or open sourcing tools, he chose to do that because he gives a shit.

In an ideal world would he have used up all of his free time to write white papers by hand, sure. But instead he used AI to help him go faster (who among us can honestly say were not using in our daily lives??)

As someone whos been a HUGE fan of his work for a long time let me add some positivty to this thread. I'm SOOO thankful that hes still spending his free time doing incredible research, releasing functional documented open source, and bothering to release white papers. When so many researchers I see today slap a cheeky logo on a shitty blog post and call it awesome.

The big question is whether this can break out of KVM and whether it can be microrode patched / patched in any other way.

And whether it's really real in the first place.

I spaghettify my memory every time I write C code.
This is a great starting point to go looking for PSP / SMM backdoors.
My absolute favorite HN article of all time, to date!

Absolutely brilliant!

The vendor locked regions (on hardware that you already own!) that this could unlock (or help future security researchers to unlock, in the case of later model CPU's) has the potential to solve many auditability/transparency/defensive security/repair (cf. "Right to Repair") problems in the future.

Christopher Domas has earned the right to be called a 'Legend' -- again!

(For probably like what, the 3rd or 4th time now? :-))

Anyway, upvoted and favorited!

Where did this guy come from? Suddenly I’m seeing new amazing hardware exploits from them every day!

https://news.ycombinator.com/from?site=github.com/xoreaxeaxe...

Fascinating. So what is the DCT swizzling functionality designed for in the hardware originally?
This is the level of access the rightful owner of a computer should have to his own system.

He should also be able to fuse away this access forever, to be fair. But out of the box, when I get a new laptop, I should be able to read and write every byte of DRAM.

I don't understand the threat model being attacked here. If you had physical DRAM access you could do all of this anyway right? And I would assume that an unprivileged user would not have write access to the DRAM controller registers?
I’m confused. Why is this remapping option exposed to userspace?
Holy shit, Christopher Domas is back. I remember watching his Defcon talks on x86 shenanigans[^1][^2] and being amazed at what he's been able to discover. Then he got whisked away by Intel and now drops this. I'm excited.

[^1]: https://www.youtube.com/watch?v=XH0F9r0siTI

[^2]: https://www.youtube.com/watch?v=jmTwlEh8L7g

Holy crap. This is like a software-reachable version of the dynamic memory aliasing hardware attack demonstrated by https://batteringram.eu/
So what's inside Intel ME, AMD PSP and associaded firmwares? Don't leave us hanging here...
On IntelME/AMD PSP:

https://jxself.org/titanic.shtml

He did it well. On "security", the author loves more to own his code/adata than anything. as did the PDP10/ITS hackers.

Would you be able to put a payload into EEPROM with this?
This is so cool. Outside of a cool demo, and maybe some black hat type stuff, this is surely dangerous, a bad idea, and shouldn't be done in prod. But pure hacker ethos at its heart.
So nice to see Christopher Domas posting code again.
This requires Ring 0 already, correct? That would seriously limit its usefulness for hacks or jailbreaks.
Opus refuses to discuss this at all. Make of that what you will.
Needs more emojis
This is quite excellent.
This is probably very interesting, but does it really have to be explained with a solid wall of AI slop writing?
What a fuckin legend
Could someone ELI5 please? Context, achievement, scope, consequences?
Skitter creek bath salts... Or SCBS Guess there'll be a talk called Secure Computing BullShit in the next Blackhat conf! I'll be eagerly waiting for it! :)