Secure IFrame Implementation

This page demonstrates a secure implementation of iframes with all recommended security features to minimize vulnerabilities. Pink Sock should not detect any security issues with this implementation.

Security Features: This page implements proper iframe sandboxing, content security policy, and cross-origin protections.

Secure Example

Secure code:

<iframe 
  src="../assets/iframe-content.html" 
  sandbox="allow-scripts allow-popups-to-escape-sandbox"
  allow="camera=(), microphone=()"
  loading="lazy"
  referrerpolicy="no-referrer"
  title="Securely sandboxed iframe content"
  width="100%"
  height="300"
></iframe>

Security Features Explained

Sandbox Attribute

The sandbox attribute is properly configured with the minimum necessary permissions:

allow-scripts - Permits JavaScript execution within the iframe
allow-popups-to-escape-sandbox - Allows popups but ensures they're not sandboxed

Notably absent are:

allow-same-origin - Would defeat sandbox protections when combined with allow-scripts
allow-top-navigation - Could enable clickjacking attacks
allow-forms - Omitted to prevent the risky combination with allow-scripts that could enable phishing

Important Security Note: While allow-forms is often necessary for functionality, combining it with allow-scripts can create potential security risks. If form submission is required, consider additional protections such as proper CSP form-action directives and implementing anti-CSRF measures.

Additional Security Attributes

allow="camera=(), microphone=()" - Explicitly blocks access to camera and microphone
loading="lazy" - Improves performance and reduces resource usage
referrerpolicy="no-referrer" - Prevents leaking referrer information
title - Provides accessibility and helps document the iframe's purpose

Content Security Policy

The page includes a strong Content Security Policy that:

Restricts resources to the same origin with default-src 'self'
Controls which frames can be embedded with frame-src 'self'
Prevents clickjacking with frame-ancestors 'self'
Blocks object embedding with object-src 'none'

Best Practices for Secure IFrames

Security Checklist

Always use the sandbox attribute with the principle of least privilege
Never combine allow-scripts with allow-same-origin
Be cautious when combining allow-scripts with allow-forms
Include a strong Content Security Policy
Use referrerpolicy to control information leakage
Explicitly control permissions with the allow attribute
Only load content from trusted sources
Consider srcdoc for static content instead of external URLs
Add title attribute for accessibility
Use loading="lazy" for performance benefits

Security Trade-offs

Some combinations of features involve security trade-offs:

Feature Combination	Risk Level	Mitigation
`allow-scripts` + `allow-same-origin`	High	Never use this combination as it defeats sandboxing
`allow-scripts` + `allow-forms`	Medium	Use only when necessary and add CSP form-action constraints
`allow-scripts` + `allow-top-navigation`	Medium	Use `allow-top-navigation-by-user-activation` instead

Additional Protection Layers

For critical applications, consider adding:

Subresource Integrity (SRI) checks for loaded resources
Cross-Origin Resource Sharing (CORS) headers
Cross-Origin Resource Policy (CORP) headers
Cross-Origin Opener Policy (COOP) headers
Cross-Origin Embedder Policy (COEP) headers