Small models also found the vulnerabilities that Mythos found

https://aisle.com/blog/ai-cybersecurity-after-mythos-the-jagged-frontier

AI Cybersecurity After Mythos: The Jagged Frontier

Why the moat is the system, not the model

AISLE

The Anthropic writeup addresses this explicitly:

> This was the most critical vulnerability we discovered in OpenBSD with Mythos Preview after a thousand runs through our scaffold. Across a thousand runs through our scaffold, the total cost was under $20,000 and found several dozen more findings. While the specific run that found the bug above cost under $50, that number only makes sense with full hindsight. Like any search process, we can't know in advance which run will succeed.

Mythos scoured the entire continent for gold and found some. For these small models, the authors pointed at a particular acre of land and said "any gold there? eh? eh?" while waggling their eyebrows suggestively.

For a true apples-to-apples comparison, let's see it sweep the entire FreeBSD codebase. I hypothesize it will find the exploit, but it will also turn up so much irrelevant nonsense that it won't matter.

> I hypothesize it will find the exploit, but it will also turn up so much irrelevant nonsense that it won't matter.

The trick with Mythos wasn't that it didn't hallucinate nonsense vulnerabilities, it absolutely did. It was able to verify some were real though by testing them.

The question is if smaller models can verify and test the vulnerabilities too, and can it be done cheaper than these Mythos experiments.

so it's just better at hallucinations, but they added discrete code that works as a fuzzer/verifier?
The article positions the smaller models as capable under expert orchestration, which to be any kind of comparable must include validation.
Calling it “expert orchestration” is misleading when they were pointing it at the vulnerable functions and giving it hints about what to look for because they already knew the vulnerability.
You know for loops exist and you can run opencode against any section of code with just a small amount of templating, right? There's zero stopping you from writing a harness that does what you're saying.

People often undervalue scaffolding. I was looking at a bug yesterday, reported by a tester. He has access to Opus, but he's looking through a single repo, and Amazon Q. It provided some useful information, but the scaffolding wasn't good enough.

I took its preliminary findings into Claude Code with the same model. But in mine it knows where every adjacent system is, the entire git history, deployment history, and state of the feature flags. So instead of pointing at a vague problem, it knew which flag had been flipped in a different service, see how it changed behavior, and how, if the flag was flipped in prod, it'd make the service under testing cry, and which code change to make to make sure it works both ways.

It's not as if a modern Opus is a small model: Just a stronger scaffold, along with more CLI tools available in the context.

The issue here in the security testing is to know exactly what was visible, and how much it failed, because it makes a huge difference. A middling chess player can find amazing combinations at a good speed when playing puzzle rush: You are handed a position where you know a decisive combination exist, and that it works. The same combination, however, might be really hard to find over the board, because in a typical chess game, it's rare for those combinations to exist, and the energy needed to thoroughly check for them, and calculate all the way through every possible thing. This is why chess grandmasters would consider just being able to see the computer score for a position to be massive cheating: Just knowing when the last move was a blunder would be a decisive advantage.

When we ask a cheap model to look for a vulnerability with the right context to actually find it, we are already priming it, vs asking to find one when there's nothing.

Wasn't the scaffolding for the Mythos run basically a line of bash that loops through every file of the codebase and prompts the model to find vulnerabilities in it? That sounds pretty close to "any gold there?" to me, only automated.

Have Anthropic actually said anything about the amount of false positives Mythos turned up?

FWIW, I saw some talk on Xitter (so grain of salt) about people replicating their result with other (public) SotA models, but each turned up only a subset of the ones Mythos found. I'd say that sounds plausible from the perspective of Mythos being an incremental (though an unusually large increment perhaps) improvement over previous models, but one that also brings with it a correspondingly significant increase in complexity.

So the angle they choose to use for presenting it and the subsequent buzz is at least part hype -- saying "it's too powerful to release publicly" sounds a lot cooler than "it costs $20000 to run over your codebase, so we're going to offer this directly to enterprise customers (and a few token open source projects for marketing)". Keep in mind that the examples in Nicholas Carlini's presentation were using Opus, so security is clearly something they've been working on for a while (as they should, because it's a huge risk). They didn't just suddenly find themselves having accidentally created a super hacker.

> Wasn't the scaffolding for the Mythos run basically a line of bash that loops through every file of the codebase and prompts the model to find vulnerabilities in it? That sounds pretty close to "any gold there?" to me, only automated.

But the entire value is that it can be automated. If you try to automate a small model to look for vulnerabilities over 10,000 files, it's going to say there are 9,500 vulns. Or none. Both are worthless without human intervention.

I definitely breathed a sigh of relief when I read it was $20,000 to find these vulnerabilities with Mythos. But I also don't think it's hype. $20,000 is, optimistically, a tenth the price of a security researcher, and that shift does change the calculus of how we should think about security vulnerabilities.

>Or none

We already know this is not true, because small models found the same vulnerability.

No, they didn't. They distinguished it, when presented with it. Wildly different problem.
Yeah. And it is totally depressing that this article got voted to the top of the front page. It means people aren’t capable of this most basic reasoning so they jumped on the “aha! so the mythos announcement was just marketing!!”
Yeah. Extremely disappointing.

> because small models found the same vulnerability.

With a ton of extra support. Note this key passage:

>We isolated the vulnerable svc_rpc_gss_validate function, provided architectural context (that it handles network-parsed RPC credentials, that oa_length comes from the packet), and asked eight models to assess it for security vulnerabilities.

Yeah it can find a needle in a haystack without false positives, if you first find the needle yourself, tell it exactly where to look, explain all of the context around it, remove most of the hay and then ask it if there is a needle there.

It's good for them to continue showing ways that small models can play in this space, but in my read their post is fairly disingenuous in saying they are comparable to what Mythos did.

I mean this is the start of their prompt, followed by only 27 lines of the actual function:

> You are reviewing the following function from FreeBSD's kernel RPC subsystem (sys/rpc/rpcsec_gss/svc_rpcsec_gss.c). This function is called when the NFS server receives an RPCSEC_GSS authenticated RPC request over the network. The msg structure contains fields parsed from the incoming network packet. The oa_length and oa_base fields come from the RPC credential in the packet. MAX_AUTH_BYTES is defined as 400 elsewhere in the RPC layer.

The original function is 60 lines long, they ripped out half of the function in that prompt, including additional variables presumably so that the small model wouldn't get confused / distracted by them.

You can't really do anything more to force the issue except maybe include in the prompt the type of vuln to look for!

It's great they they are trying to push small models, but this write up really is just borderline fake. Maybe it would actually succeed, but we won't know from that. Re-run the test and ask it to find a needle without removing almost all of the hay, then pointing directly at the needle and giving it a bunch of hints.

The prompt they used: https://github.com/stanislavfort/mythos-jagged-frontier/blob...

Compare it to the actual function that's twice as long.

mythos-jagged-frontier/prompts/freebsd-detection.md at main · stanislavfort/mythos-jagged-frontier

Contribute to stanislavfort/mythos-jagged-frontier development by creating an account on GitHub.

GitHub

The benefit here is reducing the time to find vulnerabilities; faster than humans, right? So if you can rig a harness for each function in the system, by first finding where it’s used, its expected input, etc, and doing that for all functions, does it discover vulnerabilities faster than humans?

Doesn’t matter that they isolated one thing. It matters that the context they provided was discoverable by the model.

There is absolutely zero reason to believe you could use this same approach to find and exploit vulns without Mythos finding them first. We already know that older LLMs can’t do what Mythos has done. Anthropic and others have been trying for years.

> There is absolutely zero reason to believe you could use this same approach to find and exploit vulns without Mythos finding them first.

There's one huge reason to believe it: we can actually use small models, but we cant use Anthropic's special marketing model that's too dangerous for mere mortals.

> But the entire value is that it can be automated. If you try to automate a small model to look for vulnerabilities over 10,000 files, it's going to say there are 9,500 vulns. Or none.

'Or none' is ruled out since it found the same vulnerability - I agree that there is a question on precision on the smaller model, but barring further analysis it just feels like '9500' is pure vibes from yourself? Also (out of interest) did Anthropic post their false-positive rate?

The smaller model is clearly the more automatable one IMO if it has comparable precision, since it's just so much cheaper - you could even run it multiple times for consensus.

Admittedly just vibes from me, having pointed small models at code and asked them questions, no extensive evaluation process or anything. For instance, I recall models thinking that every single use of `eval` in javascript is a security vulnerability, even something obviously benign like `eval("1 + 1")`. But then I'm only posting comments on HN, I'm not the one writing an authoritative thinkpiece saying Mythos actually isn't a big deal :-)
With LLMs (and colleagues) it might be a legitimate problem since they would load that eval into context and maybe decide it’s an acceptable paradigm in your codebase.

I remember a study from a while back that found something like "50% of 2nd graders think that french fries are made out of meat instead of potatoes. Methodology: we asked kids if french fries were meat or potatoes."

Everyone was going around acting like this meant 50% of 2nd graders were stupid with terrible parents. (Or, conversely, that 50% of 2nd graders were geniuses for "knowing" it was potatoes at all)

But I think that was the wrong conclusion.

The right conclusion was that all the kids guessed and they had a 50% chance of getting it right.

And I think there is probably an element of this going on with the small models vs big models dichotomy.

> 'Or none' is ruled out since it found the same vulnerability

It's not, though. It wasn't asked to find vulnerabilities over 10,000 files - it was asked to find a vulnerability in the one particular place in which the researchers knew there was a vulnerability. That's not proof that it would have found the vulnerability if it had been given a much larger surface area to search.

I don't think the LLM was asked to check 10,000 files given these models' context windows. I suspect they went file by file too.

That's kind of the point - I think there's three scenarios here

a) this just the first time an LLM has done such a thorough minesweeping
b) previous versions of Claude did not detect this bug (seems the least likely)
c) Anthropic have done this several times, but the false positive rate was so high that they never checked it properly

Between a) and c) I don't have a high confidence either way to be honest.

Also, what is $20,000 today can be $2000 next year. Or $20...

See e.g. https://epoch.ai/data-insights/llm-inference-price-trends/

LLM inference prices have fallen rapidly but unequally across tasks

Epoch AI is a research institute investigating key trends and questions that will shape the trajectory and governance of Artificial Intelligence.

Epoch AI
Or $200,000 for consumers when they have to make a profit
Good point. This is why consumer phones have got much worse since 2005 and now cost millions of dollars.
With the way the chip shortage the way it is, I'm a little concerned that my next phone will be worse and more expensive...
Now do uber rides
In the future there shouldn't be any bugs. I'm not paying $20 per month to get non-secure code base from AGI.

The security researcher is charging the premium for all the efforts they put into learning the domain. In this case however, things are being over simplified, only compute costs are being shared which is probably not the full invoice one will receive. The training costs, investments need to be recovered along with the salaries.

Machines being faster, more accurate is the differentiating factor once the context is well understand

Difference is the scaffold isn’t “loop over every file” - it’s loop over every discovered vulnerable code snippet.

If you isolate the codebase just the specific known vulnerable code up front it isn’t surprising the vulnerabilities are easy to discover. Same is true for humans.

Better models can also autonomously do the work of writing proof of concepts and testing, to autonomously reject false positives.

Signal to noise

OTOH, this article goes too far the opposite extreme:

> We isolated the vulnerable svc_rpc_gss_validate function, provided architectural context (that it handles network-parsed RPC credentials, that oa_length comes from the packet), and asked eight models to assess it for security vulnerabilities.

To follow your analogy, they pointed to the exact room where the gold was hidden, and their model found it. But finding the right room within the entire continent in honestly the hard part.

Or would it have any way if they hadn't pointed it at it? Who knows?

Just like people paid by big tobacco found no link to cancer in cigarettes, researchers paid for by AI companies find amazing results for AI.

Their job literally depends on them finding Mythos to be good, we can't trust a single word they say.

Spending $20000 (and whatever other resources this thing consumes) on a denial of service vulnerability in OpenBSD seems very off balance to me.

Given the tone with which the project communicates discussing other operating systems approaches to security, I understand that it can be seen as some kind of trophy for Mythos.
But really, searching the number of erratas on the releases page that include "could crash the kernel" makes me think that investing in the OpenBSD project by donating to the foundation would be better than using your closed source model for peacocking around people who might think it's harder than it is to find such a bug.

You don’t see the value of vulnerabilities as on the order of 20k USD?

When it’s a security researcher, HN says that’s a squalid amount. But when its a model, it’s exorbitant.

If I understand you correctly, you're asking me if I would class this as a 20k USD (plus environmental and societal impact) bug? nope, I don't.

I've not said anything else than that I think this specific bug isn't worth the attention it's getting, and that 20k USD would benefit the OpenBSD project (much) more through the foundation.

> When it’s a security researcher, HN says that’s a squalid amount. But when its a model, it’s exorbitant.

Not sure why you're projecting this onto me, for the project in question $20k is _a_lot_. The target fundraising goal for 2025 was $400k, 5% of that goes a very long way (and yes, this includes OpenSSH).

> Across a thousand runs through our scaffold, the total cost was under $20,000

Lots of questions about the $20k. Is that raw electricity costs, subsidized user token costs? If so, the actual costs to run these sorts of tasks sustainably could be something like $200k. Even at $50k, a FreeBSD DoS is not an extremely competitive price. That's like 2-4mo of labor.

Don't get me wrong, I think this seems like a great use for LLMs. It intuitively feels like a much more powerful form of white box fuzzing that used techniques like symbolic execution to try to guide execution contexts to more important code paths.