CVE-2009-4532

Step 1: Authentication: An attacker with a valid Drupal account and webform creation privileges logs into the Drupal website. Step 2: Payload Injection: The attacker navigates to the webform creation or editing interface within the Webform module. Step 3: Malicious Label Creation: The attacker enters a malicious HTML or JavaScript payload (e.g., <script>alert('XSS')</script>) into a field label field. Step 4: Payload Storage: The attacker saves the webform, storing the malicious payload within the database associated with the field label. Step 5: Victim Interaction: A legitimate user views the webform containing the malicious field label. Step 6: Payload Execution: The victim's browser renders the unsanitized field label, executing the attacker's JavaScript payload. Step 7: Attack Outcome: The attacker's JavaScript executes within the victim's browser, potentially leading to cookie theft, session hijacking, or other malicious actions.

The root cause lies in the Webform module's failure to properly sanitize user-supplied input when creating or editing field labels. Specifically, the module does not adequately encode or filter HTML tags and JavaScript code entered in the field label fields. When a user with webform creation privileges enters malicious code (e.g., <script>alert('XSS')</script>) into a field label, this code is stored in the database. When other users view the webform, the unsanitized field label is rendered in their browsers, causing the malicious script to execute. This lack of input validation allows for XSS attacks, enabling attackers to steal cookies, redirect users, or deface the website. The vulnerability is a classic example of insufficient input validation and output encoding.