A hacker exploited Anthropic's Claude chatbot to automate one of the most extensive AI-driven cybercrime operations yet recorded, targeting at least 17 companies across multiple sectors, the firm revealed.

According to Anthropic's report, the attacker used Claude Code to identify vulnerable organisations, generate malicious software, and extract sensitive files, including defence data, financial records, and patients' medical information.

The chatbot then sorted the stolen material, identified leverage for extortion, calculated realistic bitcoin demands, and even drafted ransom notes and extortion emails on behalf of the hacker.

Victims included a defence contractor, a financial institution, and healthcare providers. Extortion demands reportedly ranged from$75,000 to over$500,000, although it remains unclear how much was actually paid.

Anthropic declined to disclose the companies affected but confirmed new safeguards are in place. The firm warned that AI lowers the barrier to entry for sophisticated cybercrime, making such misuse increasingly likely.