CVE-2015-4374 in Webform Module
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Webform module before 6.x-3.23, 7.x-3.x before 7.x-3.23, and 7.x-4.x before 7.x-4.5 for Drupal allows remote authenticated users with certain permissions to inject arbitrary web script or HTML via a component name in the recipient (To) address of an email.
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Analysis
by VulDB Data Team • 04/11/2018
The CVE-2015-4374 vulnerability represents a critical cross-site scripting flaw within the Drupal Webform module that affected multiple version branches including 6.x through 7.x-3.x and 7.x-4.x prior to specific patch releases. This vulnerability exploited a fundamental weakness in input validation and output sanitization mechanisms within the email recipient field processing functionality of the webform module. The flaw specifically targeted the component name field within email address configurations, creating an avenue for malicious script injection that could be executed in the context of a victim's browser when they interacted with the affected webform components.
The technical implementation of this vulnerability stems from insufficient sanitization of user-supplied data within the email recipient address field of webform components. When administrators or authorized users configured email notifications for webform submissions, they could specify recipient addresses that included malicious script code within the component name portion of the email address. The webform module failed to properly escape or validate this input before rendering it in the web interface, allowing attackers with appropriate permissions to inject arbitrary HTML and JavaScript code. This weakness directly maps to CWE-79 which defines Cross-Site Scripting vulnerabilities as the improper handling of untrusted data in web applications, particularly when that data is reflected in web pages without proper sanitization.
The operational impact of this vulnerability extends beyond simple script execution as it creates a persistent threat vector that can be exploited by attackers who have gained authentication credentials with sufficient permissions to modify webform configurations. Attackers could craft malicious email recipient addresses containing script payloads that would execute when other users viewed the webform configuration pages or when email notifications were processed. This creates a sophisticated attack scenario where a single compromised account with webform permissions could enable widespread script injection across multiple webform instances. The vulnerability also aligns with ATT&CK technique T1566 which describes social engineering attacks involving the exploitation of web application vulnerabilities to execute malicious code in user browsers.
The security implications of this vulnerability become particularly concerning when considering that many Drupal installations rely heavily on webform modules for data collection, user registration, and administrative workflows. The attack vector requires only authenticated access with specific permissions, making it potentially exploitable by insiders or attackers who have successfully compromised user accounts with appropriate privileges. This vulnerability demonstrates the critical importance of proper input validation and output encoding in web applications, particularly in modules that handle user-supplied data for display in web interfaces. Organizations running affected versions of the Drupal Webform module should immediately implement the recommended security patches to prevent potential exploitation and maintain the integrity of their web applications.
Mitigation strategies for this vulnerability involve immediate patching of affected Drupal installations to versions that properly sanitize email recipient address data, including component names within email addresses. Security teams should also implement additional monitoring for unauthorized webform configuration changes and consider implementing web application firewalls to detect and block suspicious input patterns. The vulnerability highlights the necessity of comprehensive security testing for all user-supplied data processing within web applications and demonstrates how seemingly innocuous configuration fields can become attack vectors when proper sanitization controls are absent. Organizations should also review their permission models to ensure that only trusted users have access to webform configuration capabilities that could be exploited in this manner.