Data Exfiltration (Agents)

In depth

Data exfiltration is when an agent is manipulated into sending private data it can reach to a place the attacker controls. Any outbound channel works: an HTTP request to an API, loading an image, or a link for the user to click, which is why Simon Willison counts external communication as one leg of the lethal trifecta. Real incidents have also used commits and public comments. Defenses focus on the channel rather than the prompt: egress allowlists, no automatic rendering of images and links, and keeping secrets out of the agent's environment.

Primary source: simonwillison.net