How can I apply this recommendation on VPN portal?
Recommendations
Implement a Content Security Policy (CSP) by configuring HTTP headers on your web server.
Clearly define trusted sources for scripts, styles, images, fonts, etc., using directives like 'script-src,' 'style-src,' 'img-src.'
Use nonce or hash values for inline scripts and styles to allow specific exceptions while maintaining security.
Regularly review and update the CSP configuration to adapt to changes and emerging security threats.
Test the effectiveness of the CSP by simulating potential attack scenarios and monitor violation reports.
Educate development teams on CSPs and secure coding practices to prevent the introduction of vulnerabilities.
Consider incremental deployment, starting with a more permissive policy and gradually tightening restrictions.