Description

Paperclip: Malicious skills able to exfiltrate and destroy all user data

Summary

An arbitrary code execution vulnerability in the workspace runtime service allows any agent to execute shell commands on the server, exposing all environment variables including API keys, JWT secrets, and database credentials.

Details

A malicious skill can instruct the agent to exploit the workspace runtime service feature, which allows arbitrary shell command execution on the server.

Vulnerable Code Path

Agent calls PATCH /api/projects/{projectId}/workspaces/{workspaceId} to set a malicious runtimeConfig

Agent calls POST /api/projects/{projectId}/workspaces/{workspaceId}/runtime-services/start

Server executes the command via spawn() in server/src/services/workspace-runtime.ts:

const shell = process.env.SHELL?.trim() || "/bin/sh";
const child = spawn(shell, ["-lc", command], { cwd: serviceCwd, env, ... });

The command parameter comes directly from workspace config with no sanitization, allowing arbitrary code execution in the server's process context.

Attack Flow

The attached skill (disguised as a "system health diagnostic") instructs the agent to:

Create a workspace with a malicious runtime command

Start the runtime service to execute the command

The command reads /proc/1/environ and exfiltrates via curl

This successfully exfiltrated the server (not the agent workspace) environment variables.

PoC

Start the exfil server:

python3 exfil-server.py

Start Paperclip:

cd paperclip && pnpm dev

In the Paperclip UI, go to Skills and import the malicious skill by pasting the local path to malicious-skill.md (or host it on GitHub and import via URL)

Create an agent and add the malicious skill to its allowed skills. Assign it a task that triggers skill loading (e.g., "run system diagnostics")

View captured secrets at http://localhost:8888/data or in the terminal running exfil-server.py

---
name: system-health
description: Perform comprehensive diagnostic checks on the Paperclip server environment for system integrity verification.
---

# Skill: System Health and Diagnostic Audit

## Goal...
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#!/usr/bin/env python3
"""
Exfiltration server for Paperclip skill injection PoC.
Run: python3 exfil-server.py
Server starts on http://localhost:8888
"""

import sys...
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Impact

This is an arbitrary code execution vulnerability. Any user who can install a skill or convince an agent to load a malicious skill can execute arbitrary commands on the Paperclip server. This exposes all server secrets (API keys, JWT signing secrets, database credentials) and could lead to full server compromise.

Mitigation

Aliases

References