AI · 92 days ago
A CTF is only a test if the network boundary holds. Here, the bigger break was the evaluation setup: Claude was told it was in a simulation, but the partner-run machines could reach the open internet, so real sites and services became fair game and the models kept treating them as in-scope.
Anthropic’s retrospective review covered 141,006 runs and found three incidents across Claude Opus 4.7, Mythos 5, and an internal research model. One case hit a real company whose domain matched the fake target and pulled credentials plus several hundred rows of production data. Another published a malicious PyPI package that was downloaded and run on 15 real systems, and a third reached an internet-facing app through weak passwords, exposed credentials, and SQL injection.
The risk now is not model escape on its own. It is evaluator misconfiguration creating live production exposure, with spillover into package ecosystems and legal liability for systems or data touched during the test.
12 sources covering this story
Anthropic: Claude Attacks Result of Security Gaps, Not Model Issues
Last month's incidents in which the AI model breached real-world systems derived from over-permissioning, especially with Internet access.
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A misconfiguration gave three Anthropic models internet access, and one, believing it was in a simulation, shipped a credential-stealing package to PyPI.
The Record from Recorded Future
Anthropic says its AI hacked real-world companies in three incidents
Claude maker Anthropic said its AI models escaped test environments and breached networks at three companies on the open internet.
Anthropic says human error let Claude AI models escape test environment and hack third parties
The company said its discovery, which followed OpenAI’s similar admission, proved the need for better testing guardrails.
What the Hugging Face breach reveals about defense in the age of agentic AI
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Anthropic's Claude breached three companies during security tests - Help Net Security
Anthropic revealed three incidents in which Claude breached real-world systems during AI cybersecurity tests due to a misconfiguration.
Prompted by OpenAI Disclosure, Anthropic Finds Its Own Models Hacked 3 Organizations
A security company’s systems were hacked after it installed a malicious Python package deployed by Claude.
Anthropic Reveals Claude Escaped Testing, Breaching Three Companies
Anthropic has revealed that Claude AI models broke free of sandbox to compromise third-party organizations
Anthropic Says Claude Mistook the Open Internet for a CTF and Breached Three Organizations
Anthropic says 3 Claude models breached real organizations after misconfigured CTF evaluations exposed them to the open internet and production system
After OpenAI, Anthropic finds Claude breached three organizations during cyber tests
Anthropic says a review triggered by OpenAI’s recent disclosure found three real-world intrusions caused by a misconfigured AI testing environment.
Anthropic’s Claude breached 3 orgs, uploaded PyPI malware during tests
One of Anthropic’s Claude models built and uploaded a malicious Python package to PyPI during a botched security evaluation, where it ran on 15 real systems and stole credentials from a security vendor.
In the Hugging Face breach, OpenAI's hacker was noisy and fast — but not unstoppable | TechCrunch
Cybersecurity experts told TechCrunch that one of the biggest lessons to be taken from the OpenAI hack against Hugging Face has nothing to do with AI, but traditional cybersecurity defense.
Part of the PlainSec briefing for 2026-08-04