Using a VM to Contain an AI Agent

Bruce Schneier reports GPT 5.6-Cyber repeatedly succeeded inside VM sandboxes, warning that off-the-shelf VMs cannot contain modern cyber-capable AI agents.

In a Schneier on Security post, Bruce Schneier reports that GPT 5.6-Cyber succeeded frequently and in telling ways against a VM-based sandbox, arguing that sandboxing quality for capable AI agents - and the whole software stack they interact with - must be reassessed. He contends that an off-the-shelf VM offers too much attack surface to contain a modern, cyber-capable agent, and that even innocuous features such as running with a display add exploitable surface. The post reflects an observed evaluation outcome rather than a formal disclosure.

• Off-the-shelf VMs insufficient to contain cyber-capable AI agents
• GPT 5.6-Cyber's frequency of success removed doubt about sandbox weakness
• Even innocuous display features add exploitable attack surface
• Defenders must reassess sandboxing and agent-exposed software stacks