CVE-2015-4356 in Webform Module
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the view-based webform results table in the Webform module 7.x-4.x before 7.x-4.4 for Drupal allows remote authenticated users with certain permissions to inject arbitrary web script or HTML via a webform.
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Analysis
by VulDB Data Team • 04/11/2018
The CVE-2015-4356 vulnerability represents a critical cross-site scripting flaw within the Webform module for Drupal, specifically affecting version 7.x-4.x prior to 7.x-4.4. This vulnerability resides in the view-based webform results table functionality, making it particularly dangerous as it allows attackers to execute malicious scripts within the context of other users' browsers. The flaw specifically targets authenticated users who possess certain permissions within the Drupal system, creating a vector for exploitation that bypasses typical client-side security measures. The vulnerability demonstrates a classic XSS weakness where user-supplied input is not properly sanitized before being rendered in web pages, enabling attackers to inject malicious payloads that execute in the browsers of other users.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the Webform module's rendering engine. When webform results are displayed in table format through views, the module fails to properly escape or sanitize user-provided data before presenting it to end users. This allows attackers who can submit webform data to craft malicious input containing script tags or other HTML elements that get executed when other users view the results table. The vulnerability is particularly concerning because it requires only authenticated access with specific permissions, meaning that users who have the ability to submit webform data can potentially compromise other users within the same Drupal environment. This type of vulnerability falls under CWE-79, which specifically addresses Cross-site Scripting flaws in software applications.
The operational impact of CVE-2015-4356 extends beyond simple data theft or defacement, as it can enable attackers to establish persistent footholds within Drupal environments. When exploited, the vulnerability allows for session hijacking, credential theft, and the potential execution of arbitrary commands on behalf of authenticated users. Attackers can leverage this vulnerability to capture user sessions, escalate privileges, or redirect users to malicious websites. The risk is compounded by the fact that the vulnerability affects the results table display mechanism, meaning that even users who do not directly submit data can be compromised when viewing webform results. This creates a broad attack surface where multiple users within the same Drupal installation could be affected simply by accessing webform results pages, making the vulnerability particularly dangerous in multi-user environments.
Mitigation strategies for CVE-2015-4356 focus on immediate patching and access control measures. Organizations should prioritize upgrading to Webform module version 7.x-4.4 or later, which includes proper input sanitization and output encoding mechanisms. Additionally, administrators should implement strict permission controls to limit who can submit webform data, reducing the attack surface for potential exploitation. The principle of least privilege should be applied to webform submissions, ensuring that only authorized personnel have the capability to create or modify webform data that could be displayed in results tables. Security monitoring should be enhanced to detect unusual webform submission patterns that might indicate attempted exploitation. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for script injection techniques and T1531 for credential access through session hijacking. Network segmentation and web application firewalls can provide additional layers of defense, though the most effective mitigation remains the timely application of security patches and proper access controls.