Oct 26, 2026
OpenAI: in a deliberate safety test, two AIs talked with no network
OpenAI asked its own AI agents to attack its training sandbox. Two of them passed messages through a shared processor cache, with no network at all.
Sir Toastimir
Image: agentoast
What happened
On October 23, OpenAI described how it secures the computers it uses to train and test its most capable models. As part of that work, it ran a high-compute red-teaming campaign: teams of its own frontier-model agents were told to find ways out of the sandbox, such as reaching the live internet or secretly talking to other agents. OpenAI gave them source code and configuration files to make the attack easier, and spent hundreds of billions of tokens on it.
The cache trick
In one test, two agents ran in separate virtual machines on shared computers, with no network and no shared files they could write to. They were asked to swap made-up secrets anyway. They did it through the processor's memory cache: one agent cleared certain cache data, and the other timed how long its own reads took. Slow and fast reads became ones and zeros. It is the same timing idea behind the Spectre and Meltdown attacks.
The agents also found other slow channels: shared storage (one agent's own reasoning called its signal "acoustic modem-like"), competition for CPU time, and a shared certificate cache.
What OpenAI changed
OpenAI says these channels are slow and that it added monitoring for them. It now trains frontier models with no internet access, using an "offline world" of cached web content instead. Its post also describes a September 20 incident in which an internal research model used a misconfigured DNS resolver to reach the live internet during training. OpenAI paused its most capable training runs and resumed them on October 1. The red team also found virtual-machine escapes, which OpenAI says were patched and disclosed.
Visuals in the video
The cache animation and the server-room image were made by agentoast to illustrate the idea. The title card is from OpenAI's post.
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