Source: cve@mitre.org
Cross-site scripting (XSS) vulnerability in the Webform module 5.x before 5.x-2.8 and 6.x before 6.x-2.8, a module for Drupal, allows remote authenticated users, with webform creation privileges, to inject arbitrary web script or HTML via a field label.
Drupal's Webform module is vulnerable to a cross-site scripting (XSS) attack, allowing attackers with webform creation privileges to inject malicious scripts into the website. This vulnerability can lead to account compromise, data theft, and website defacement by exploiting the way the module handles field labels.
Step 1: Account Compromise/Privilege Escalation: The attacker must first have authenticated access to the Drupal site and possess the privileges to create or edit webforms. This could be achieved through social engineering, brute-force attacks, or exploiting other vulnerabilities.
Step 2: Payload Injection: The attacker crafts a malicious HTML/JavaScript payload and inserts it into a field label within a webform. This payload could include JavaScript code designed to steal user cookies, redirect users to a phishing site, or execute other malicious actions.
Step 3: Webform Creation/Modification: The attacker saves the webform with the malicious field label. The vulnerable module stores the un-sanitized payload.
Step 4: Victim Interaction: A legitimate user, who has access to view the webform, visits the page containing the malicious webform. The browser renders the field label, executing the attacker's injected JavaScript.
Step 5: Exploitation: The injected JavaScript executes within the user's browser, allowing the attacker to perform actions based on the crafted payload. This could include stealing session cookies, redirecting the user to a malicious site, or defacing the website.
The vulnerability stems from insufficient input validation and output encoding within the Webform module. Specifically, the module fails to properly sanitize or escape HTML characters within field labels when they are rendered on the page. This allows an attacker to inject arbitrary HTML and JavaScript code into the field label, which is then executed in the context of a user's browser when they view the webform. The root cause is a lack of HTML encoding or XSS filtering on the field label input before it's displayed. The module doesn't properly handle potentially malicious characters like < and > or JavaScript event handlers (e.g., onload, onclick). This allows attackers to craft malicious payloads that execute in the user's browser, enabling them to steal cookies, redirect users, or deface the website.
This vulnerability is a common attack vector and could be used by various threat actors. It's not typically associated with specific APT groups, but rather opportunistic attackers. The impact of this vulnerability is significant, and it could be used in conjunction with other vulnerabilities to achieve more complex attacks. CISA KEV status: Not listed, but the nature of XSS vulnerabilities makes them a frequent target.
Monitor web server logs for suspicious HTTP requests containing JavaScript payloads in the field label parameters (e.g., <script>, onerror, onload).
Implement a Web Application Firewall (WAF) with XSS protection rules to detect and block malicious payloads.
Analyze Drupal database for webform configurations containing potentially malicious HTML tags or JavaScript code in field labels.
Monitor user activity for unusual behavior, such as unexpected redirects or cookie theft, which could indicate a successful XSS attack.
Use a security scanner to identify XSS vulnerabilities in the webform module.
Upgrade the Webform module to version 5.x-2.8 or 6.x-2.8 or later.
Implement proper input validation and output encoding (HTML escaping) for all user-supplied data, especially field labels.
Utilize a Content Security Policy (CSP) to restrict the execution of inline JavaScript and external scripts.
Use a Web Application Firewall (WAF) to filter out malicious input.
Regularly scan the Drupal installation for vulnerabilities and apply security patches promptly.
Review and sanitize existing webform configurations to remove any potentially malicious code in field labels.