There's a lot of discourse on Twitter about people using LLMs to solve CTF challenges.
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Hoshino Lina (星乃リナ) 🩵 3D Yuri Wedding 2026!!!, yeah I only automatically reload actors when I receive activities from them and more than 24 hours has passed since the previous reload. Now that you've sent me a reply, it did trigger that. Maybe I should do the same when fetching things like a post that someone boosted.
@grishka Yeah I think that name was possibly a year+ old ^^;;
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And honestly, reading the Claude output, it's just ridiculous. It clearly has no idea what it's doing and it's just pattern-matching. Once it found the flag it spent 7 pages of reasoning and four more scripts trying to verify it, and failed to actually find what went wrong. It just concluded after all that time wasted that sometimes it gets the right answer and sometimes the wrong answer and so probably the flag that looks like a flag is the flag. It can't debug its own code to find out what actually went wrong, it just decided to brute force try again a different way.
It's just a pattern-matching machine. But it turns out if you brute force pattern-match enough times in enough steps inside a reasoning loop, you eventually stumble upon the answer, even if you have no idea how.
Humans can "wing it" and pattern-match too, but it's a gamble. If you pattern-match wrong and go down the wrong path, you just wasted a bunch of time and someone else wins. Competitive CTFs are all about walking the line between going as fast as possible and being very careful so you don't have to revisit, debug, and redo a bunch of your work. LLMs completely screw that up by brute forcing the process faster than humans.
This sucks.
AI is fast eradicating any learning activity.
In my current job, learning anything new is actively discouraged.As was said to us "they only care about numbers on a dashboard".
I got to the position I am in, at the level at I am in, by being curious and very interested, in taking things apart, and figuring out how they work.
A LLM, which, in the eyes of a CEO means he can get rid of people like me, is the end of the road, we are all doomed.
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@lina@vt.social To be fair I'd argue this is strictly a people problem
I feel like this is the inherent nature of competition in places where cooperation would make much more sense
And this issue permeates so many areas that the world is more preoccupied with catching the people cheating the system instead of going "hey maybe this system could incentivize actually getting invested into the thing instead of being a pure so-called meritocracy "@natty But the whole point of a for-fun(/prize) competition is to use the gamification to motivate people... that's kind of what games are?
You don't strictly need it, you can publish challenges to be solved for no points and no prize... but that demonstrably does not get as many people interested. Between people for whom that works, and the "I just want to win" people who would use LLMs, there are people who would be motivated to compete but not just self-study, and you lose those when the LLM cheaters come in.
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@lina I do feel like this is about how you use the LLM. I often find my self throwing something into my local llama to give me an ELI5 or what do these flags on this command do in combination.
But as someone who has Designed CTFs and watched someone fling through it without learning a damn thing, it can be hard to keep the faith.
When I took physics all those years ago my professor made us learn a slide rule before a calculator. If you skip over the basics and use a machine to do it..when the machine breaks or is wrong, who is gonna fix it and how?
@ahasty But at least a calculator is always right. I have no problem with people using tools that can be understood and are reliable/engineered.
The problem is LLMs are not that. They cannot be understood, they are black boxes that just brute force their way through things. So they are particularly and uniquely toxic in the harm they cause, compared to the tools we've had until now as part of the general industrial/technology revolution.
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@lina
CTF = Capture the Flag, in case that helps anyone besides meI try to do for initialisms and acronyms what alt text does for images.
Wikipedia: In computer security, Capture the Flag (CTF) is an exercise in which participants attempt to find text strings, called "flags", which are secretly hidden in purposefully vulnerable programs or websites
@shansterable @lina I had to look it up. The next most popular definition of CTF was Children's Tumor Foundation...
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@ahasty But at least a calculator is always right. I have no problem with people using tools that can be understood and are reliable/engineered.
The problem is LLMs are not that. They cannot be understood, they are black boxes that just brute force their way through things. So they are particularly and uniquely toxic in the harm they cause, compared to the tools we've had until now as part of the general industrial/technology revolution.
@lina yes, they are a black box. If used as a way to help educate yourself there is value. When used as means to an end, you kill the pipeline of problem solving. Unfortunately the unwavering force of capitalism is almost always short sighted
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And honestly, reading the Claude output, it's just ridiculous. It clearly has no idea what it's doing and it's just pattern-matching. Once it found the flag it spent 7 pages of reasoning and four more scripts trying to verify it, and failed to actually find what went wrong. It just concluded after all that time wasted that sometimes it gets the right answer and sometimes the wrong answer and so probably the flag that looks like a flag is the flag. It can't debug its own code to find out what actually went wrong, it just decided to brute force try again a different way.
It's just a pattern-matching machine. But it turns out if you brute force pattern-match enough times in enough steps inside a reasoning loop, you eventually stumble upon the answer, even if you have no idea how.
Humans can "wing it" and pattern-match too, but it's a gamble. If you pattern-match wrong and go down the wrong path, you just wasted a bunch of time and someone else wins. Competitive CTFs are all about walking the line between going as fast as possible and being very careful so you don't have to revisit, debug, and redo a bunch of your work. LLMs completely screw that up by brute forcing the process faster than humans.
This sucks.
@lina that's the worst part IMO. We get Claude through work and, all environmental and ethical issues aside, I just hate using it. Curating mounds of garbage output from the Screw It Up Faster Machine sucks. But it looks *great* in artificial evaluations with a concrete, machine-verifiable goal. And too many managers don't understand that real world programming isn't just passing a succession of concrete, machine-verifiable goals.
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So it's not surprising that an LLM can solve them, because it automates the process. That just takes all the fun and all the learning out of it, completely defeating the purpose.
I'm sure you could still come up with challenges that LLMs can't solve, but they would necessarily be harder, because LLMs are going to oneshot any of the "baby" starter challenges you could possibly come up with. So you either get rid of the "baby" challenges entirely (which means less experienced teams can't compete at all), or you accept that people will solve them with LLMs. But neither of those actually works.
Since CTF competitions are pretty much by definition timed, speed is an advantage. That means a team that does not use LLMs will not win, so teams must use LLMs. This applies to both new and experienced teams. But: A newbie team using LLMs will not learn. Because the whole point is learning by doing, and you're not doing anything. And so will not become experienced.
So this is going to devolve into CTFs being a battle of teams using LLMs to fight for the top spots, where everyone who doesn't want to use an LLM is excluded, and where less experienced teams stop improving and getting better, because they're outsourcing the work to LLMs and not learning as a result.
@lina Already in 2022 for the "European Cyber Cup" CTF at least one of the top3 team had ChatGPT open before even checking what some of the challenges were about 🫠
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And honestly, reading the Claude output, it's just ridiculous. It clearly has no idea what it's doing and it's just pattern-matching. Once it found the flag it spent 7 pages of reasoning and four more scripts trying to verify it, and failed to actually find what went wrong. It just concluded after all that time wasted that sometimes it gets the right answer and sometimes the wrong answer and so probably the flag that looks like a flag is the flag. It can't debug its own code to find out what actually went wrong, it just decided to brute force try again a different way.
It's just a pattern-matching machine. But it turns out if you brute force pattern-match enough times in enough steps inside a reasoning loop, you eventually stumble upon the answer, even if you have no idea how.
Humans can "wing it" and pattern-match too, but it's a gamble. If you pattern-match wrong and go down the wrong path, you just wasted a bunch of time and someone else wins. Competitive CTFs are all about walking the line between going as fast as possible and being very careful so you don't have to revisit, debug, and redo a bunch of your work. LLMs completely screw that up by brute forcing the process faster than humans.
This sucks.
@lina LLMs can't reason
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@lina LLMs can't reason
@dngrs @lina We don't doubt that, but here's used with a different meaning, there's no word for this process that doesn't also have a definition of an uniquely human ability. And, for example, saying that a machine "thinks" is nothing new, I was saying that 20+ years ago whenever a computer was stuck doing something which would finish eventually. Particularly if it was a virtual game opponent (which we also called AI because the term has always been that broad).
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AI is fast eradicating any learning activity.
In my current job, learning anything new is actively discouraged.As was said to us "they only care about numbers on a dashboard".
I got to the position I am in, at the level at I am in, by being curious and very interested, in taking things apart, and figuring out how they work.
A LLM, which, in the eyes of a CEO means he can get rid of people like me, is the end of the road, we are all doomed.
@Sonic2k @lina your looking at it the wrong way. Yes it’s killing one type of learning. But it’s teaching you how to CTF using AI, what are it strengths and weaknesses, what prompts are effective? What sub problems should the AI tackle, what should the human focus on. It’s no different than a carpenter switching from a hand plane to a powered belt sander. The skill set changes, the results are more or less the same. Someone that only learns to belt sand isn’t less of a carpenter. It gatekeeping to think otherwise. Yes the “elitist artists” will argue otherwise, but the difference is moot for the vast bulk of us working stiffs.
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@lina I wonder if you can still design a challenge to be "LLM unfriendly" by changing the wording, just like those papers showing how an LLM aces problems like "river crossing", but if you change wording a bit, they just fail in weird and spectacular ways.
@doragasu @lina Probably. LLMs are hilariously bad at dealing with linguistic ambiguities like puns.
One of my favorite ambiguities I’ve seen was saying some people “lie about the family tree”. Are they being deceptive on the topic of relations, or are they reclining around a plant tended by multiple generations?
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@Sonic2k @lina your looking at it the wrong way. Yes it’s killing one type of learning. But it’s teaching you how to CTF using AI, what are it strengths and weaknesses, what prompts are effective? What sub problems should the AI tackle, what should the human focus on. It’s no different than a carpenter switching from a hand plane to a powered belt sander. The skill set changes, the results are more or less the same. Someone that only learns to belt sand isn’t less of a carpenter. It gatekeeping to think otherwise. Yes the “elitist artists” will argue otherwise, but the difference is moot for the vast bulk of us working stiffs.
@Jmj @Sonic2k @lina classic ai apologist "expertise is unnecessary" fallacy. The results are perhaps similar on the surface "was the task completed" level but if person does it and learns the details an LLM can brute force past, that person can then recognize the issues showcased without going out of their way to look for them, which is a incredibly important part for security work. Because the real world is far messier and less clear than a CTF, and part of dealing with that is the kind of intuition and almost subconscious understanding which is impossible to achieve by using an LLM. And CTFs used to be decent at finding and rewarding those who are good at that.
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@Alib234 @lina AIs are better than humans will ever be at chess and this was the case 20 years ago.
We ban AIs in chess.
It's a pain to detect but it's incredibly important for the integrity of the game.
And it about communicating norms and values too, "we don't want AI" is an incredibly different set of values than "we want AI in only xyz ways"
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@nightwolf Yeah, I'm thinking mostly Jeopardy, which is the style I'm most familiar with. It just sucks to see that competition format completely break. I used to write a lot of challenges for that.
@lina Agreed. It will be interesting to see the next few years since Jeopardy format has been the most popular and easiest to implement.
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And honestly, reading the Claude output, it's just ridiculous. It clearly has no idea what it's doing and it's just pattern-matching. Once it found the flag it spent 7 pages of reasoning and four more scripts trying to verify it, and failed to actually find what went wrong. It just concluded after all that time wasted that sometimes it gets the right answer and sometimes the wrong answer and so probably the flag that looks like a flag is the flag. It can't debug its own code to find out what actually went wrong, it just decided to brute force try again a different way.
It's just a pattern-matching machine. But it turns out if you brute force pattern-match enough times in enough steps inside a reasoning loop, you eventually stumble upon the answer, even if you have no idea how.
Humans can "wing it" and pattern-match too, but it's a gamble. If you pattern-match wrong and go down the wrong path, you just wasted a bunch of time and someone else wins. Competitive CTFs are all about walking the line between going as fast as possible and being very careful so you don't have to revisit, debug, and redo a bunch of your work. LLMs completely screw that up by brute forcing the process faster than humans.
This sucks.
@lina maybe it would work to take a page from my areas of expertise, locks and psychology. Make trap flags that lead AIs into false solutions that humans can identify and step out of, but that AI thinks is the right way forward.
Update: I tried about a dozen decoy flags, and ChatGPT was surprisingly good at picking out the correct one. The only ones where it failed were when the flag decoded into what looked like a valid flag, but it was an instruction to enter something else.
Like:
- CTF_3NT3RTH1SFL4GBKWDS
- CTF_F0110WD1R3CT10NS
