CVE-2015-6658 in Drupal
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Autocomplete system in Drupal 6.x before 6.37 and 7.x before 7.39 allows remote attackers to inject arbitrary web script or HTML via a crafted URL, related to uploading files.
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Analysis
by VulDB Data Team • 06/13/2022
The CVE-2015-6658 vulnerability represents a critical cross-site scripting flaw within Drupal's Autocomplete system affecting versions 6.x prior to 6.37 and 7.x prior to 7.39. This vulnerability resides in the file upload functionality where the system fails to properly sanitize user-supplied input before processing it within the autocomplete mechanism. The flaw allows remote attackers to execute malicious scripts in the context of a victim's browser, potentially leading to session hijacking, data theft, or unauthorized actions on behalf of authenticated users. The vulnerability specifically manifests when crafted URLs containing malicious payloads are processed through the file upload interface, where the Autocomplete system does not adequately validate or escape user input before rendering it in the browser. This issue directly maps to CWE-79, which defines improper neutralization of input during web page generation, commonly known as cross-site scripting. The vulnerability operates within the ATT&CK framework under the T1203 category of Exploitation for Client Execution, where adversaries leverage web application vulnerabilities to execute malicious code in user browsers. The impact of this vulnerability extends beyond simple script injection as it can be exploited to bypass security controls and escalate privileges within the Drupal environment. Attackers can craft malicious URLs that, when processed through the vulnerable file upload system, will execute arbitrary JavaScript code in the browser of any user who interacts with the affected system. The vulnerability demonstrates a classic lack of input validation and output encoding that has been a persistent challenge in web application security. The flaw occurs because the Autocomplete system does not properly escape special characters in file names or URL parameters before they are rendered in HTML contexts. This creates an environment where attackers can inject HTML tags, JavaScript code, or other malicious content that executes when the page loads. The vulnerability affects both Drupal 6 and 7 versions, indicating a widespread issue within the platform's core functionality that required immediate patching. Organizations running affected Drupal versions face significant risk as the vulnerability can be exploited without authentication, making it particularly dangerous for public-facing websites. The security implications extend to potential data breaches, as attackers can steal session cookies, access user information, or manipulate content management systems. Mitigation strategies include applying the official patches released by Drupal for versions 6.37 and 7.39, implementing proper input validation at multiple layers, and configuring web application firewalls to detect and block suspicious URL patterns. Additionally, organizations should conduct thorough security assessments of their Drupal installations to identify any other potential vulnerabilities in related systems. The vulnerability underscores the importance of proper output encoding and input validation in web applications, particularly when handling user-supplied data in contexts where it may be rendered in HTML or JavaScript environments. This flaw serves as a reminder of the critical need for comprehensive security testing and the implementation of defense-in-depth strategies to protect against client-side exploitation techniques.