Securing Web Radar Apps: Fixing Unauthenticated Real-Time Data Exposure

Introduction

It's a story as old as software development itself: a tool built for internal use, never intended to be "secure" in a formal sense, ends up exposed on a network with no authentication whatsoever. This week, we're examining exactly that scenario — a high-severity vulnerability (V-005) discovered and patched in a web radar application's frontend (external/webradar/webapp/src/app.jsx).

The vulnerability allowed any attacker on the same local network to navigate to the web radar URL without credentials and view live, real-time game state data derived from direct memory reads of a running process. No username. No password. No token. Just... open access.

If you're a developer who has ever thought "it's just an internal tool, it doesn't need auth" — this post is for you.

The Vulnerability Explained

What Was Happening?

The web radar application was designed to fetch and display real-time data — player positions, map data, and other game state information — sourced from DMA (Direct Memory Access) reads of the CS2 game process. This data was served as data.json files from a backend server and rendered in the browser via app.jsx.

The critical problem? The server had no authentication mechanism. If the server was bound to a network-accessible interface (rather than strictly localhost), the attack surface was wide open.

Here's the threat model in plain terms:

• The web radar server starts and binds to a network interface (e.g., 0.0.0.0:PORT or a LAN IP).
• The React frontend at app.jsx fetches and renders this live data.
• Any device on the same network — a roommate's laptop, a compromised IoT device, a coffee shop neighbor — can simply open a browser and navigate to http://<server-ip>:<port> to see everything.

The Real-World Impact

This might sound niche, but the implications are broader than they first appear:

1. Information Disclosure: The data.json files contained raw memory-derived data. Memory-derived data can inadvertently expose host memory addresses, internal system pointers, or other sensitive runtime information about the host machine.

2. Privacy Violation: Real-time positional data, game state, and behavioral patterns of users are exposed without consent to anyone who stumbles upon (or actively scans for) the server.

3. Lateral Movement Risk: In a corporate or shared network environment, an unauthenticated internal service is a gift to an attacker performing reconnaissance. Exposed memory addresses can assist in bypassing ASLR (Address Space Layout Randomization) or crafting further exploits.

4. Supply Chain & Integrity Risk: The application also uses nodejs-file-downloader with no evidence of cryptographic verification (checksum or signature validation) for downloaded content. This compounds the risk — a MITM attacker could not only view data but potentially tamper with downloaded files.

Attack Scenario: The Coffee Shop Attacker

Imagine this scenario:

[Attacker's Laptop] ──── [Coffee Shop WiFi] ──── [Your Laptop running Web Radar]

1. You launch your web radar tool on your laptop at a LAN gaming event or shared network.
2. The server binds to 0.0.0.0:8080 (all interfaces).
3. An attacker runs a simple network scan: nmap -sV 192.168.1.0/24 -p 8080
4. They find your server, open http://192.168.1.42:8080 in their browser.
5. They're now watching your live game state — positions, map data, everything — in real time.
6. Bonus: the raw data.json response leaks memory addresses from your host machine.

No exploit code needed. No CVE required. Just a browser and an IP address.

The Fix

What Changed

The patch addresses the core issue: adding an authentication mechanism to the web radar server and its frontend interface. The fix was applied to external/webradar/webapp/src/app.jsx (line 112) and the associated server configuration.

The key security improvements introduced by this fix include:

1. Authentication Gate on the Frontend

Before the fix, app.jsx would immediately begin fetching and rendering live data with no credential check:

// BEFORE: No authentication check — data fetched immediately
useEffect(() => {
  const fetchData = async () => {
    const response = await fetch('/data.json');
    const json = await response.json();
    setGameState(json);
  };
  const interval = setInterval(fetchData, 100);
  return () => clearInterval(interval);
}, []);

After the fix, the application verifies authentication state before initiating any data fetch:

// AFTER: Authentication check before data access
const [isAuthenticated, setIsAuthenticated] = useState(false);

useEffect(() => {
  if (!isAuthenticated) return; // Don't fetch without auth

  const fetchData = async () => {
    const response = await fetch('/data.json', {
      headers: {
        'Authorization': `Bearer ${getSessionToken()}`
      }
    });

    if (response.status === 401) {
      setIsAuthenticated(false); // Token expired or invalid
      return;
    }

    const json = await response.json();
    setGameState(json);
  };

  const interval = setInterval(fetchData, 100);
  return () => clearInterval(interval);
}, [isAuthenticated]);

2. Server-Side Authentication Enforcement

The backend server was updated to require valid credentials before serving any data, ensuring that even direct API calls (bypassing the frontend entirely) are blocked:

// Server-side middleware: reject unauthenticated requests
app.use('/data.json', (req, res, next) => {
  const token = req.headers['authorization']?.split(' ')[1];

  if (!token || !validateToken(token)) {
    return res.status(401).json({ error: 'Unauthorized' });
  }

  next();
});

3. Localhost Binding Recommendation

As part of defense-in-depth, the server configuration was updated to default to localhost-only binding, dramatically reducing the network exposure:

// BEFORE
app.listen(8080); // Binds to 0.0.0.0 by default

// AFTER
app.listen(8080, '127.0.0.1'); // Explicitly localhost-only

How Does This Solve the Problem?

The fix applies the principle of least privilege and defense in depth:

• Authentication ensures only authorized users can access the data stream.
• Token validation on every request means a stolen session can be revoked server-side.
• Localhost binding means even if authentication were somehow bypassed, the attack surface is limited to the local machine.
• 401 handling in the frontend ensures the UI gracefully handles expired or invalid sessions rather than silently failing or leaking partial data.

Conclusion

The V-005 vulnerability in app.jsx is a perfect case study in how convenience-driven shortcuts in internal tooling can create serious security exposures. A tool designed for a specific, controlled use case was left without authentication — and in doing so, it exposed real-time, memory-derived sensitive data to anyone on the same network.

The fix is straightforward: add authentication, bind to localhost, validate downloaded content, and treat internal tools with the same security rigor as production systems.

Key takeaways:

🔐 There is no such thing as "too internal to need authentication."

🌐 Binding to 0.0.0.0 without authentication is an open invitation.

🔍 Memory-derived data should never be served raw over a network.

✅ Cryptographic verification of downloaded content is non-negotiable.

Security isn't a feature you add at the end — it's a practice you embed from the first line of code. Whether you're building a production SaaS platform or a weekend hobby tool, the principles are the same.

Stay secure, validate your inputs, authenticate your users, and bind your servers to localhost until you have a very good reason not to.

This vulnerability was identified and patched by OrbisAI Security. Automated security scanning + human review = fewer surprises in production.