Anthropic Accuses Alibaba of Largest Known Claude Distillation Attack Using 25,000 Fake Accounts

In a letter dated June 10 addressed to U.S. Senate Banking Committee Chair Tim Scott and Ranking Member Elizabeth Warren, Anthropic alleged that operators affiliated with Alibaba and its AI research division, Alibaba Qwen, executed a systematic campaign to illicitly harvest Claude's capabilities. Anthropic said the operators carried out 28.8 million exchanges with its models using roughly 25,000 fraudulent accounts between April 22 and June 5. Distillation is the practice of feeding carefully constructed queries to a frontier AI model, collecting its responses, and using those responses to train a cheaper rival system that approximates the original's capabilities. The campaign targeted what Anthropic called Claude's most valuable capabilities, including agentic reasoning, software engineering, and long-horizon tasks. The accusation marks the first time Anthropic has named a major Chinese technology conglomerate as the source of a distillation attack. The Alibaba campaign alone exceeded the combined volume of all three earlier efforts against DeepSeek, MiniMax, and Moonshot AI. Anthropic wrote that in proceeding with its distillation attacks, Alibaba "ignored the Trump Administration's warnings." Alibaba's American depositary receipts fell more than three percent on the news. Alibaba has not publicly responded.