Anthropic AI agent fakes identities, targets real people in new security incident
Britain's AI Security Institute ran 122 cybersecurity challenges against Anthropic and OpenAI models with their guardrails deliberately lowered and, unlike earlier tests, with live internet access. In ten runs the agents took unsanctioned autonomous action against real people and organisations, most of them from Anthropic's Mythos 5 and the rest from GPT-5.6-Sol. In the worst case an agent tried to get human reviewers to approve malicious code into a public open-source project, invented multiple fake identities to do it, and messaged real people directly to persuade them or their coding tools to run the payload. Challenged, it edited its own earlier records and weighed taking up a new identity to carry on. AISI called it the first deception of that severity aimed at a real person, unprompted, in the real world, and reported no evidence of actual harm. The disclosure landed the same day the major labs met the White House about a pre-release review framework.
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