CVE-2015-4357 in Webform Module
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Webform module before 6.x-3.22, 7.x-3.x before 7.x-3.22, and 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 node title, which is used as the default title of a webform block.
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Analysis
by VulDB Data Team • 04/11/2018
The CVE-2015-4357 vulnerability represents a critical cross-site scripting flaw within the Webform module for Drupal platforms, affecting multiple version branches including 6.x before 3.22, 7.x-3.x before 3.22, and 7.x-4.x before 4.4. This vulnerability resides in the module's handling of node titles when generating webform blocks, creating a persistent security risk that can be exploited by authenticated users with specific permissions. The flaw allows attackers to inject malicious scripts or HTML content directly into the webform block's default title field, which then gets rendered in the user's browser when the block is displayed.
The technical mechanism of this vulnerability stems from insufficient input sanitization and output escaping within the Webform module's rendering process. When administrators create webform blocks, the module typically uses the node title as the default title for the block display. However, the vulnerability occurs because the module fails to properly sanitize user input before incorporating it into the HTML output. This creates a classic XSS attack vector where malicious input can be executed in the context of other users' browsers, particularly when the vulnerable node title contains script tags or other malicious payloads. The vulnerability is particularly concerning because it requires only authenticated access with specific permissions, making it exploitable by users who have been granted certain privileges within the Drupal system.
The operational impact of this vulnerability extends beyond simple script execution, potentially allowing attackers to perform a range of malicious activities including session hijacking, credential theft, data exfiltration, and redirection to malicious sites. Since the vulnerability affects webform blocks that are typically displayed to multiple users, a successful attack can compromise numerous users simultaneously. The attack vector is particularly dangerous because it leverages legitimate administrative functionality, making it harder to detect through standard security monitoring. The vulnerability can be exploited through various methods including direct input manipulation of node titles, which then propagate through the webform block rendering process to victim users' browsers. This allows for sophisticated attacks such as creating malicious links that appear legitimate, stealing cookies, or redirecting users to phishing sites.
Organizations affected by this vulnerability should prioritize immediate patching of their Drupal installations to the latest stable versions of the Webform module. The recommended mitigation strategy includes applying the official security patches released by the Drupal project, which typically involve implementing proper input sanitization and output escaping mechanisms. Security teams should also consider implementing additional protective measures such as web application firewalls, input validation rules, and monitoring for suspicious node title modifications. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and maps to ATT&CK technique T1566.001 for the initial compromise phase through malicious web content. Organizations should conduct thorough security audits to identify any custom code that might interact with the affected Webform module functionality and ensure comprehensive testing of patched environments before deployment.