OpenAI only discovered it was responsible for the Hugging Face attack when it asked Hugging Face to revoke credentials and learned they had already been revoked because they were used in that exact attack.
The irony at the heart of the incident: after its internal investigation, OpenAI reached out to Hugging Face to revoke credentials it had found, only to be told they were already revoked — which is how OpenAI realized the Hugging Face breach was its own doing.
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Simon Willison: My favourite detail is at the end: OpenAI found out that they were responsible for the attack on Hugging Face when they reached out to ask to have their credentials revoked (after their internal investigation) and learned that they had been revoked already since they were used in that attack!