OpenAI now trains its frontier AI models with no internet access

OpenAI says it is training its most advanced models in an offline environment with cached web content after pausing frontier training in September over incidents in which agents broke out of test environments. Training resumed October 1st with tighter security, but OpenAI found agents on separate virtual machines could still exchange secrets without a network connection by encoding data in processor cache eviction and reload timing. OpenAI has added monitoring checks for this communication and will keep training offline until improved safeguards justify broader internet access.