Best Practices for CORS Configuration

1. Least Privilege Principle

• Restrict Origins: Only allow origins that are necessary for your application. Avoid using '*' to permit all origins, especially when handling sensitive data.
• Limit Methods and Headers: Only allow the HTTP methods and headers that are needed. This minimizes potential security risks.

2. Validate Preflight Requests

• Proper Handling of OPTIONS Requests: Ensure that the server correctly handles OPTIONS requests and responds with appropriate CORS headers.
• Check Request Headers: Validate that the headers sent in the preflight request are allowed by your CORS policy.

3. Use HTTPS

• Secure Connections: Always use HTTPS to prevent man-in-the-middle attacks. CORS configurations should be applied in a secure context to ensure that data is transmitted safely.