A critical vulnerability was discovered in an invite system where crafted HTML injection allowed attackers to perform account takeovers. This type of attack can lead to unauthorized access, data breaches, and complete system compromise if not mitigated properly.
You Should Know: How HTML Injection Leads to Account Takeover
1. Understanding HTML Injection
HTML Injection occurs when an attacker injects malicious HTML or JavaScript into a web application, which is then rendered by the browser. In this case, the invite system failed to sanitize user input, allowing attackers to manipulate the system.
2. Exploitation Steps
Here’s how an attacker could exploit this vulnerability:
Step 1: Crafting the Malicious Payload
The attacker creates an HTML payload that triggers unauthorized actions, such as:
<form action="https://victim-site.com/invite/accept" method="POST"> <input type="hidden" name="user_id" value="attacker_id"> <input type="hidden" name="token" value="stolen_token"> <input type="submit" value="Click to Claim Reward"> </form>
Step 2: Injecting the Payload
The attacker sends the malicious invite link to victims:
https://victim-site.com/invite?payload=<form+action%3D"https%3A%2F%2Fvictim-site.com%2Finvite%2Faccept"+method%3D"POST">+<input+type%3D"hidden"+name%3D"user_id"+value%3D"attacker_id">+<input+type%3D"hidden"+name%3D"token"+value%3D"stolen_token">+<input+type%3D"submit"+value%3D"Click+to+Claim+Reward">+</form>
Step 3: Victim Interaction
When the victim clicks the link, the injected form may auto-submit (if JavaScript is used), leading to an account takeover.
3. Mitigation Techniques
To prevent such attacks:
- Input Sanitization: Use libraries like `DOMPurify` to clean HTML inputs.
- Content Security Policy (CSP): Restrict inline scripts and unauthorized sources.
- CSRF Tokens: Ensure all state-changing requests require a valid CSRF token.
Example: Sanitizing Input in Node.js
const DOMPurify = require('dompurify');
const cleanInput = DOMPurify.sanitize(userInput);
Linux Command to Test for XSS Vulnerabilities
curl -X POST "https://target.com/invite" --data "payload=<script>alert(1)</script>"
Windows PowerShell: Checking for HTML Injection in Logs
Get-Content .\web_logs.txt | Select-String "<script|javascript:|onerror="
What Undercode Say
HTML injection remains a severe threat in web applications, especially in invite systems where user input is directly rendered. Attackers can manipulate DOM elements, steal session tokens, and hijack accounts. Developers must enforce strict input validation, implement CSP headers, and conduct regular security audits.
Expected Output:
- A secure invite system that sanitizes all user inputs.
- Logs showing blocked malicious HTML/JS attempts.
- No unauthorized account takeovers due to injected payloads.
Prediction
As web applications grow more complex, HTML injection attacks will evolve, leveraging new DOM manipulation techniques. Automated scanning tools and AI-based security solutions will become essential in detecting such vulnerabilities early.
(Note: No relevant URLs were found in the original post to include.)
References:
Reported By: Akshachudasama23 Bugbounty – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
