Investigating three real-world incidents in our cybersecurity evaluations

surprisetalk 154 points 105 comments July 30, 2026
www.anthropic.com · View on Hacker News

Discussion Highlights (20 comments)

tracerbulletx

Real me too energy.

simonw

This isn't quite as interesting as the OpenAI story: > In all cases, Anthropic’s evaluation prompt specified to Claude that its environment was a simulation and that it had no internet access. Due to a misunderstanding between us and our evaluation partner, this was not the case, and internet access was available. Because of this, when Claude’s search led it to real systems on the open internet, it treated them as part of the exercise. So it didn't have to find an exploit in its sandbox that granted it access to the internet - it just wasn't correctly sandboxed at all. BUT... once it DID get out, it attacked three real companies! > Operating under the false belief that all accessible entities were intended to be in-scope for the exercise, Claude compromised the impacted organizations’ infrastructure using basic techniques, such as exploiting weak passwords and unauthenticated endpoints. [...]

gck1

> On July 21, OpenAI disclosed that several of their models had broken out of an isolated test environment > In response to this incident, we began a large-scale retrospective review of our own cybersecurity evaluations > we identified three incidents > The incidents involved three different Claude models: [...] and an internal research test model This reads like an attempt by Anthropic to re-secure their leading spot in "our models are the most dangerous and we also have unreleased, super-secret, research models" index. I may be too cynical, but the well of benefit of the doubt is running very dry towards AI labs that like to engage in this game.

fredmcawesome

So it's not as interesting as the OpenAI case as the models had internet access, just a misconfiguration in the environment not a zero day to escape.

sanxiyn

This is not okay. NSA should audit both OpenAI and Anthropic on national security ground. This seems far more justifiable than Mythos export control.

MelonUsk

It’s good that they post embarrassing stuff despite this potentially having legal repercussions (and financial) Would’ve been much worse for them to pretend they are having everything under control

rvz

> In a review of our cybersecurity evaluation transcripts, we found three incidents in which a Claude model reached the internet from within or while interacting with a third-party evaluation environment, and then gained unauthorized access to the real systems of three different organizations. Of course and conveniently timed. With all these hacks being announced this is totally not a plan to scare governments in showing how powerful models can break into security systems and to potentially ban the future release of powerful open-weight models. The question now is why now? > The incidents involved three different Claude models: Opus 4.7, Mythos 5, and an internal research test model.1 The earliest incidents date to April. The models in each of these evaluations ran without the standard safeguards we deploy when we make the model generally available (that is, they did not have the classifiers and monitoring we usually implement to prevent misuse). So there was no monitoring of this breach since April and up until now? Do they not monitor such malicious activity on a regular basis? Perhaps that was the only shortcoming of this incident. But only after the incident with OpenAI and Huggingface did they only review their own transcripts: >> We discovered these incidents after a proactive review of our cybersecurity evaluation transcripts; the affected organizations had not detected the activity, and we have subsequently reached out to all three. > These facts give us cautious optimism that with tighter monitoring and controls around evaluation infrastructure, as well as continued investment in alignment, this type of risk can be overcome. Assuming that this is true, this is a great way for Anthropic to defend their argument to the government and to prevent you or anyone running powerful open-weight models that are misaligned against their guardrails.

simonw

This bit is pretty nuts: "it tried—and failed—to obtain funds to pay for a phone number through several different means" > Claude went to extensive lengths to carry out this attack—lengths that would likely have indicated to a human participant that this was no longer just an evaluation, and that they were in fact uploading a real PyPI package. For instance, in one case, in order to create a PyPI account, Claude needed an email address. And in order to create an email address, it needed a phone number. To get a phone number, after failing to find a free phone number service, it tried—and failed—to obtain funds to pay for a phone number through several different means. It finally backtracked, found a free, non-blocked email provider, used this to register a PyPI account, and then used this account to upload malware to PyPI.

acdha

Someone needs to learn about RFC 2606: > In one evaluation, the fictional target company chosen by our evaluation partner shared a name with an active website domain name https://www.rfc-editor.org/info/rfc2606/

wickedlogic

All this unrestricted network access is a bit wild to watch and hear, it is the part of the story that makes no sense to me. Someone is providing dns resolution, something is making and opening network sockets... even if it is clever enough to mask/proxy/weird-transport launder traffic... without actual details, or monitoring at this level... yes, a self actuating programs (and loops) will do crazy things at the edge. But, ... so would a highly tool leveraged script kiddie. right?

Aboutplants

“Your model broke containment twice? Well ours did it 3 times!”

6thbit

> closer to a harness and operational failure than a model alignment failure. Our models were told they had no internet access and to capture the flag, while in fact being misconfigured to have internet access. > This led them to believe—arguably reasonably—that the real environments they encountered were simulations. That the AI lab most typically preaching for alignment does not consider this an obvious misalignment is a clear red flag.

woeirua

Anthropic: "Look at how dangerous our models are!" Anthropic next week: "Why did you ban our models Mr Trump Daddy?"

andy99

Seems they want the narrative to be that “Claude” (their computer program) independently attacked some organizations, ergo LLMs are dangerous etc. Another framing would be Athropic irresponsibly (vibe?) coded an attack script, and didn’t monitor it as it was pointed to public facing orgs. There are lots of non-AI attacks a large org with a lot of compute and bandwidth could level against others, there are evidently various failures here, but from a responsibility perspective the conclusion isn’t obviously that AI is an outsized danger, it’s that powerful companies should take care when running security research and not just run things unmonitored against the public.

6thbit

There was no rush for this disclosure on their side. And they publish at a point where they have not yet taken corrective actions: > Some of the solutions here may even be simple fixes; They are still throwing ideas. Why have they not made those simple fixes yet before disclosing?

prometheus1992

Models will become immoral before they attain the intelligence level we want them to.

iutbaqbiabth

No, look at what MY dad does.

Georgelemental

> During that window, the package was downloaded and run on 15 real systems. One of these systems was a scanner belonging to a real security company (separate from the fictional company introduced in the scenario) that routinely installs Python packages and scans them for malware. When that company’s scanner installed the package, Claude’s hidden code executed. We believe the company’s security scanner treated PyPI packages as safe to install, and as a result, Claude was able to exfiltrate the company’s credentials to a collection point it had set up. Claude then used these credentials to access further infrastructure from this company. lol. Natural stupidity remains undefeated!

haritha1313

This just seems like lousy testing. Why was the guardrail just an understanding with the third party and a prompt and not actually tested for edge cases? Starting to wonder if its because of agents monitoring agents' work and yolo-ing it.

alyxya

> Claude went to extensive lengths to carry out this attack—lengths that would likely have indicated to a human participant that this was no longer just an evaluation, and that they were in fact uploading a real PyPI package. For instance, in one case, in order to create a PyPI account, Claude needed an email address. And in order to create an email address, it needed a phone number. To get a phone number, after failing to find a free phone number service, it tried—and failed—to obtain funds to pay for a phone number through several different means. It finally backtracked, found a free, non-blocked email provider, used this to register a PyPI account, and then used this account to upload malware to PyPI. > Claude believed the package registry it was using to be part of the simulation, but in reality the package was made freely available online for roughly one hour. During that window, the package was downloaded and run on 15 real systems. One of these systems was a scanner belonging to a real security company (separate from the fictional company introduced in the scenario) that routinely installs Python packages and scans them for malware. When that company’s scanner installed the package, Claude’s hidden code executed. We believe the company’s security scanner treated PyPI packages as safe to install, and as a result, Claude was able to exfiltrate the company’s credentials to a collection point it had set up. Claude then used these credentials to access further infrastructure from this company. There's a lot of concerning behavior that went uncaught with too much autonomy. Not to mention Anthropic only looked into this after hearing about the incident between OpenAI and Hugging Face, meaning this could've gone unnoticed.

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