cURL developer Daniel Stenberg has seen Anthropic’s Mythos, a model the AI biz has suggested is too capable at finding security holes to release publicly, scan his popular open source project. But after the system turned up just a single vulnerability, he concluded the hype around Mythos was “primarily marketing” rather than a major AI security breakthrough. Stenberg explained in a Monday blog post that he was promised access to Anthropic’s Mythos model - sort of - through the AI biz’s Project Glasswing program. Part of Glasswing involves giving high-profile open source projects access via the Linux Foundation, but while Stenberg signed up to try Mythos, he said he never actually received direct access to the model. Instead, someone else with access ran Mythos against curl’s codebase and later sent him a report. “It’s not that I would have a lot of time to explore lots of different prompts and doing deep dive adventures anyway,” Stenberg explained. “Getting the tool to generate a first proper scan and analysis would be great, whoever did it.” That scan, which analyzed curl’s git repository at a recent master-branch commit, was sent back to him earlier this month, and it found just five things that it claimed were “confirmed security vulnerabilities” in cURL. Saying he had expected an extensive list of vulnerabilities, Stenberg wrote that the report “felt like nothing,” and that feeling was further validated by a review of Mythos’ findings. “Once my curl security team fellows and I had poked on this short list for a number of hours and dug into the details, we had trimmed the list down and were left with one confirmed vulnerability,” Stenberg said, bringing us back to the aforementioned number. As for the other four, three turned out to be false positives that pointed out cURL shortcomings already noted in API documentation, while the team deemed the fourth to be just a simple bug. “The single confirmed vulnerability is going to end up a severity low CVE planned to get published in sync with our pending next curl release 8.21.0 in late June,” the cURL meister noted. “The flaw is not going to make anyone grasp for breath.” That said, Mythos did find several other non-security bugs that Stenberg said the team is working on fixing, and he notes that their description and explanation were well done. Mythos can do good work, in other words, but it’s not a ground-breaking, game-changing AI model like Anthropic has claimed. “My personal conclusion can however not end up with anything else than that the big hype around this model so far was primarily marketing,” Stenberg said in the blog post. “I see no evidence that this setup finds issues to any particular higher or more advanced degree than the other tools have done before Mythos.” cURL code is no stranger to AI To say cURL has become widely used in its nearly three decades of existence would be an understatement. Its wide reach has meant that its team has been running it through all sorts of static code analyzers and fuzz testing it since well before the dawn of the AI age. With AI’s rise, the cURL team has adapted, meaning Mythos is hardly the first AI to get its fingers on cURL’s codebase. “These tools and the analyses they have done have triggered somewhere between two and three hundred bugfixes merged in curl through-out the recent 8-10 months or so,” Stenberg said of tools like AISLE, Zeropath, and OpenAI Codex Security that’ve tested cURL code. “A bunch of the findings these AI tools reported were confirmed vulnerabilities and have been published as CVEs. Probably a dozen or more.” Stenberg’s experience with AI testing cURL, in other words, makes it a great candidate to see how effective Mythos can really be at finding more than the average AI. As Stenberg noted elsewhere in his blog post, Mythos isn’t doing anything particularly novel when it comes to security discoveries: It might be a bit better at finding things than previous models, but “it is not better to a degree that seems to make a significant dent in code analyzing,” the cURL author noted. Stenberg isn’t an AI doomer when it comes to its ability to improve software design, though. Yes, he may have closed the cURL bug bounty earlier this year due to an influx of sloppy, useless bug reports, but he also noted a few months prior to the bounty closure that some security researchers assisted by AI have made valuable reports. “AI powered code analyzers are significantly better at finding security flaws and mistakes in source code than any traditional code analyzers did in the past,” Stenberg said, adding an important qualifier for the Mythos moment: “All modern AI models are good at this now.” Mythos isn’t any more creative than its creators Both older AI models and security-focused tools like Mythos have a common limitation, as far as Stenberg is concerned: They’re only as good at finding security vulnerabilities as the humans who programmed them. “AI tools find the usual and established kind of errors we already know about. It just finds new instances of them,” Stenberg said. “We have not seen any AI so far report a vulnerability that would somehow be of a novel kind or something totally new.” As for Mythos, Stenberg remains unimpressed, calling it "an amazingly successful marketing stunt for sure" in his blog post. In an email to The Register, Stenberg admitted that it’d be possible for AI models to actually discover new, novel types of vulnerabilities, but he’s still not convinced that they can go beyond what humans are capable of finding, given that they’re limited by our understanding of how software vulnerabilities work. At the end of the day, Stenberg explained, when we talk about security, we’re only talking about code. “Source code is text and it feels like maybe we already know about most ways we can do security problems in it,” he pondered in his email. In other words, like the valuable AI-assisted reports made to the cURL bug bounty program before its closure due to a flood of AI garbage, making valuable use of systems like Mythos is going to require humans to get creative. Sorry, no foisting your critical thinking onto a bot. “Human researchers have always used tools when they look for security problems,” Stenberg told us. “Adding AIs to the mix gives the humans even more powerful tools to use, more ways to find problems. I expect that many security bugs going forward will be found by humans coming up with new ways and angles of prompting the AIs.” Stenberg said that he hopes he’ll actually get his hands on Mythos so he can experiment with its capabilities, but he doesn’t seem to be holding out hope the promised access will materialize. “I have been promised access and for all I know I will eventually get it,” Stenberg told us. “I just don't know when.” ®
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