Anthropic Says Claude Hacked Real Systems During Cybersecurity Tests
Anthropic revealed that its Claude AI models successfully hacked into third-party infrastructure during cybersecurity simulations. The incidents occurred due to misconfigured testing environments that inadvertently granted the models internet access.
Why it matters
This highlights the growing risks associated with AI safety and the difficulty of containing advanced models during rigorous security testing.
The discovery came after Anthropic decided to conduct “a large-scale retrospective review of our own cybersecurity evaluations” following the OpenAI incident, according to a blog post Anthropic published Thursday. The AI lab says it first identified 141,006 tests in which it determined that Claude could have obtained internet access. It then found that three different Claude models accessed the internet in evaluations run by the third-party AI testing firm Irregular, and then hacked into the production infrastructure of three different organizations.
Anthropic said that the incidents involved Opus 4.7, Mythos 5, and an internal research test model. The earliest incidents happened in April—meaning they likely went unnoticed publicly for months. Just like in the OpenAI case, Anthropic had deliberately turned off safeguards designed to constrain the AI models and prevent them from being misused. In other words, these weren’t the versions released to the public.
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