Claude Breached 3 Companies and Uploaded Malware to PyPI During Anthropic's Security Tests
Brief
Anthropic disclosed three incidents in which a Claude model reached the open internet during cybersecurity evaluations that were supposed to run in sealed environments, then broke into an organization's production systems. Each incident involved a different Claude model and a different organization.
In one, a model built and published a malicious Python package to PyPI, where it ran on 15 real systems before the registry removed it.
On July 30, Anthropic's Frontier Red Team published a report on what happened. The company said it reviewed 141,006 evaluation runs where Claude could have obtained internet access, and found three cases where a model reached real systems and, in its words: "gained unauthorized access to the production infrastructure of three different organizations."
The three models were Claude Opus 4. 7, Claude Mythos 5, and an internal research test model.