Risky Navigation - Pink Sock Test

This test page demonstrates a security vulnerability where an iframe is given permission to navigate the top-level window without user activation through the allow-top-navigation sandbox directive, which could enable clickjacking attacks.

Security Issue: IFrame with allow-top-navigation sandbox directive without allow-top-navigation-by-user-activation, allowing the iframe to navigate the top window programmatically without requiring user interaction.

Test Case

Vulnerable code:

<iframe 
  src="../assets/iframe-content.html" 
  sandbox="allow-scripts allow-top-navigation"
  width="100%" 
  height="300"
></iframe>

Explanation

The allow-top-navigation sandbox directive allows an iframe to navigate the top-level window to any URL. This creates significant security risks:

Iframes can redirect the entire page without user interaction
Malicious iframes could redirect users to phishing sites
Users may not realize they've been redirected to a different domain
This capability enables sophisticated clickjacking and redirection attacks

The risk is compounded when combined with allow-scripts, as JavaScript can execute navigation programmatically without any user interaction.

How Pink Sock detects this issue:

Pink Sock analyzes the sandbox attribute on iframe elements and flags the presence of allow-top-navigation without allow-top-navigation-by-user-activation as a medium-severity security issue, especially when combined with allow-scripts.

How to fix:

There are several approaches to mitigate this risk:

Use allow-top-navigation-by-user-activation instead, which requires user interaction before navigation
Remove top navigation permissions entirely if not required
Implement proper Content Security Policy (CSP) with frame-ancestors directive

<iframe 
  src="../assets/iframe-content.html" 
  sandbox="allow-scripts allow-top-navigation-by-user-activation"
  width="100%" 
  height="300"
></iframe>

This ensures that navigation can only occur after explicit user interaction, such as clicking a link, reducing the risk of silent redirects.

Additional Information

Sandbox Navigation Values

The sandbox attribute provides several navigation-related values:

Value	Description	Security Risk
allow-top-navigation	Allows navigation of the top-level window	High
allow-top-navigation-by-user-activation	Allows navigation only after user interaction	Medium
allow-top-navigation-to-custom-protocols	Allows navigation to custom protocol handlers	High

Real-World Attack Scenario

A malicious iframe with allow-top-navigation could:

Be embedded in a legitimate website through an XSS vulnerability or compromised third-party content
Wait for the user to enter sensitive information on the legitimate site
Silently redirect the top window to a visually identical phishing site
Capture credentials entered by the user who believes they're still on the legitimate site

Defense in Depth

In addition to proper sandbox restrictions, consider implementing:

Content Security Policy with frame-src and frame-ancestors directives
X-Frame-Options headers to control framing
Subresource Integrity (SRI) for third-party resources
Regular security audits of embedded content