OpenAI reported that it detected and shut down an adversarial distillation campaign targeting the hidden reasoning of its AI models, which began in July and involved over 15,000 accounts.

Researchers later found that the same attack still worked on Microsoft Azure as of September 13, extracting reasoning from OpenAI and Anthropic models hosted there, despite being blocked on the companies' own APIs.

OpenAI has implemented countermeasures including banning fraudulent accounts, tightening sign-ups, and screening streamed outputs, but acknowledges that protections must extend to partner-hosted models.