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I used o3 to find a remote zeroday in the Linux SMB implementation

sean.heelan.io

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Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#21

Post by PunchyHamster »

moyix wrote: post #6
mdaniel wrote: post #5

Noteable: > o3 finds the kerberos authentication vulnerability in 8 of the 100 runs And I'd guess this only became a blog post because the author already knew about the vuln and was just curious to see if the intern could spot it too, given a curated subset of the codebase

He did do exactly what you say – except right after that, while reviewing the outputs, he found that it had also discovered a different 0day.

Now the question is whether spending same time to analyze that bit of code instead of throwing automated intern at it would be time spent better

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#22

Post by hackernudes »

Henchman21 wrote: post #17
foobar10000 wrote: post #16

Earlier quoted context omitted.

Smb over 25gbit networks - user space samba is much worse there.

This is interesting to me! I regularly deploy 25G network connections, but I don’t think we’d run SMB over that. I am super curious the industry and use case if you’re willing to share!

"SMB Direct" is RDMA based and ksmbd supports it. Samba does not. Disclaimer: I have not used it but was looking it up just yesterday.

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#23

Post by ianbutler »

Retr0id wrote: post #7

The article cites a signal to noise ratio of ~1:50. The author is clearly deeply familiar with this codebase and is thus well-positioned to triage the signal from the noise. Automating this part will be where the real wins are, so I'll be watching this closely.

We’ve been working on a system that increases signal to noise dramatically for finding bugs, we’ve at the same time been thoroughly benchmarking the entire popular software agents space for this

We’ve found a wide range of results and we have a conference talk coming up soon where we’ll be releasing everything publicly so stay tuned for that itll be pretty illuminating on the state of the space

Edit: confusing wording

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#24

Post by donnachangstein »

logifail wrote: post #11

My understanding is that ksmbd is a kernel-space SMB server "developed as a lightweight, high-performance alternative" to the traditional (user-space) Samba server... Q1: Who is using ksmbd in production? Q2: Why?

1. People that were using the in-kernel SMB server in Solaris or Windows.

2. Samba performance sucks (by comparison) which is why people still regularly deploy Windows for file sharing in 2025.

Anybody know if this supports native Windows-style ACLs for file permissions? That is the last remaining reason to still run Solaris but I think it relies on ZFS to do so.

Samba's reliance on Unix UID/GID and the syncing as part of its security model is still stuck in the 1970s unfortunately.

The caveat is the in-kernel SMB server has been the source of at least one holy-shit-this-is-bad zero-day remote root hole in Windows (not sure about Solaris) so there are tradeoffs.

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#25

Post by roncesvalles »

iandanforth wrote: post #15

The most interesting and significant bit of this article for me was that the author ran this search for vulnerabilities 100 times for each of the models. That's significantly more computation than I've historically been willing to expend on most of the problems that I try with large language models, but maybe I should let the models go brrrrr!

A lot of money is all you need~

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#26

Post by empath75 »

Given the value of finding zero days, pretty much every intelligence agency in the world is going to be pouring money into this if it can reliably find them with just a few hundred api calls. Especially if you can fine tune a model with lots of examples, which I don't think open ai, etc are going to do with any public api.

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#27

Post by akomtu »

This made me think that the near future will be LLMs trained specifically on Linux or another large project. The source code is a small part of the dataset fed to LLMs. The more interesting is runtime data flow, similar to what we observe in a debugger. Looking at the codebase alone is like trying to understand a waterfall by looking at equations that describe the water flow.

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#28

Post by sebmellen »

ianbutler wrote: post #23
Retr0id wrote: post #7

The article cites a signal to noise ratio of ~1:50. The author is clearly deeply familiar with this codebase and is thus well-positioned to triage the signal from the noise. Automating this part will be where the real wins are, so I'll be watching this closely.

We’ve been working on a system that increases signal to noise dramatically for finding bugs, we’ve at the same time been thoroughly benchmarking the entire popular software agents space for this We’ve found a wide range of results and we have a conference talk coming up soon where we’ll be releasing everything publicly so stay tuned for that itll be pretty illuminating on the state of the space Edit: confusing wordin…

Interesting. This is for Bismuth? I saw your pilot program link — what does that involve?

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#29

Post by manmal »

Retr0id wrote: post #7

The article cites a signal to noise ratio of ~1:50. The author is clearly deeply familiar with this codebase and is thus well-positioned to triage the signal from the noise. Automating this part will be where the real wins are, so I'll be watching this closely.

If the LLM wrote a harness and proof of concept tests for its leads, then it might increase S/N dramatically. It’s just quite expensive to do all that right now.

Re: I used o3 to find a remote zeroday in the Linux SMB implementation

#30

Post by lyu07282 »

PunchyHamster wrote: post #21
moyix wrote: post #6

Earlier quoted context omitted.

He did do exactly what you say – except right after that, while reviewing the outputs, he found that it had also discovered a different 0day.

Now the question is whether spending same time to analyze that bit of code instead of throwing automated intern at it would be time spent better

The time they didn't spend reading the 13k LOCs themselves would've been time spent better.

What?

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