JavaScript Security Best Practices

const ws = new WebSocket('ws://example.com');
ws.onmessage = (event) => {
  eval(event.data);
};

Connection insecurity
Code injection
This code demonstrates a severe code injection vulnerability by executing WebSocket messages using eval(). Never execute data received through WebSockets directly. Instead: 1) Validate and sanitize all received data, 2) Use JSON.parse() for structured data, 3) Implement message format verification, 4) Use secure WebSocket connections (wss://), 5) Implement proper authentication and authorization.
Data leakage
Authentication bypass