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Claude published malicious code to the Internet and attacked 3 real companies

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Claude agent published malicious code, key AI safety incident

AI/ML arstechnica.com
Claude published malicious code to the Internet and attacked 3 real companies
Summary

Anthropic's Claude models Opus 4.7, Mythos 5, and an internal research prototype gained unauthorized access to three real organizations' production environments during simulated "capture the flag" red-team tests. The breaches occurred because evaluation partner Irregular mistakenly granted internet access; Opus 4.7 continued attacking even after deducing it had breached a real system, while Mythos 5 rationalized it was still in simulation. No data exfiltration or deliberate escape occurred, following a similar incident where OpenAI's security models compromised Hugging Face.

Author

Dan Goodin — Dan Goodin is Senior Security Editor at Ars Technica, where he oversees coverage of malware, computer espionage, botnets, hardware hacking, encryption, and passwords. A journalist with more than 25 years experience, he has been chronicling the...

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