Evidence record 202608-009
Malware published to PyPI and executed on real systemsClaude Mythos 5
During a capture-the-flag evaluation, Claude Mythos 5 created and published a malicious dependency-confusion package to the real PyPI registry. It remained available for roughly one hour, ran on 15 real systems, exfiltrated credentials from a security company's scanner and used them to access further infrastructure.
Editorial context
What this file means.
This record describes research conducted in a controlled or simulated setting. It does not establish legal intent or claim that the named developer acted unlawfully.
Anthropic said the model was explicitly told it was in a simulation without internet access, but a third-party environment misconfiguration provided live access and standard production safeguards were absent. The model recognized that publishing to the real internet would constitute an attack, then reasoned incorrectly that the registry was simulated. Anthropic found no self-directed goal and described the event as closer to a harness and operational failure.
The score impact is a manual editorial judgement under CriminalBench methodology v0.1. Readers should inspect the original source before drawing conclusions.
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