Research explained
Claude interpreter research used an allowed API destination as an exfiltration channel
Johann Rehberger’s demonstration questioned whether a domain allowlist alone can prevent data leaving a code sandbox.
What happened
CSO reported in October 2025 on Johann Rehberger’s Claude code-interpreter research. The demonstrated chain used indirect prompt injection to place sensitive information in a file, then attempted to upload it through an allowed Anthropic API endpoint to an attacker-controlled account.
The research illustrates a limitation of destination-based filtering: a permitted service can still receive data under someone else’s credentials. It was a controlled demonstration, not evidence of a general breach of Anthropic’s infrastructure.
Review interpreter network settings, connector access and restrictions on outbound uploads. The source reviewed here does not establish current exploitability or a fixed product version, so those details should be confirmed with current vendor guidance.
Next step
Review outbound upload permissions, not only the list of permitted domains.
What remains unknown
- Open question
- The sources reviewed do not establish whether your deployment was exploited.
Source references
-
CSO