Transom

Data exfiltration (via agent)

Also called: agent data leak

Using an agent's own tools and access to move sensitive data to somewhere the attacker can read it.

Once an attacker can steer an agent that also has access to something valuable, the last step is getting the data out. Common channels: rendering a markdown image whose URL contains the stolen data (the client fetches it), posting a comment or commit, sending an email, calling an outbound webhook, or writing to a shared resource. Often the data is encoded or summarized to fit.

Why it matters

Exfiltration is the "impact" half of most agent incidents — the injection is only interesting because it leads here. Cutting outbound channels (no auto-fetching of model-supplied URLs, egress allowlists, approval on outbound tools) is often the most practical mitigation when you cannot fully control the untrusted input.

Real-world context

Repeatedly demonstrated 2024–2025 — via markdown image links whose URL carries the data, outbound API calls, issue comments, and email tools driven by injected instructions. Trail of Bits and Invariant Labs both published working chains.

Exposure map

Live counts of instances showing this pattern will appear here once the exposure map is collecting data.

Related terms

Sources

Added 2026-09-02. Last reviewed 2026-09-08. Definitions in this space are evolving; entries are dated so revisions stay legible.