CVE-2012-5538 in FileField Sources
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the FileField Sources module 6.x-1.x before 6.x-1.6 and 7.x-1.x before 7.x-1.6 for Drupal, when the field has "Reference existing" source enabled, allows remote authenticated users to inject arbitrary web script or HTML via the filename of an uploaded file.
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Analysis
by VulDB Data Team • 02/05/2018
The CVE-2012-5538 vulnerability represents a critical cross-site scripting flaw within the FileField Sources module for Drupal platforms, affecting versions prior to 6.x-1.6 and 7.x-1.6. This vulnerability specifically targets the module's handling of file uploads when the "Reference existing" source option is enabled, creating a dangerous vector for malicious actors to execute arbitrary code within the context of affected web applications. The flaw exists in the way the system processes and stores filenames from uploaded files, failing to properly sanitize user-supplied input before rendering it in web pages.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the FileField Sources module's file handling routines. When authenticated users upload files with maliciously crafted filenames, the system fails to properly escape special characters that could be interpreted as HTML or JavaScript code. This weakness allows attackers to inject malicious payloads that execute in the browsers of other users who view the affected file listings or related pages. The vulnerability is particularly concerning because it requires only authenticated access, meaning that users with legitimate permissions to upload files can exploit this flaw to compromise other users within the same Drupal environment. The attack vector specifically exploits the module's behavior when processing filenames that contain script tags or other malicious content.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, data exfiltration, and privilege escalation within the Drupal application. Since the vulnerability affects authenticated users, it can be particularly dangerous in environments where users have varying permission levels, as attackers might use this flaw to escalate privileges or access restricted content. The attack can be executed through legitimate file upload functionality, making it difficult to detect and trace back to the original source. This vulnerability directly aligns with CWE-79, which classifies cross-site scripting flaws in web applications, and can be mapped to ATT&CK technique T1059.007 for script injection attacks. The exploitation of this vulnerability can result in complete compromise of user sessions and potentially the entire web application if proper access controls are not in place.
Organizations affected by this vulnerability should immediately apply the security patches released by Drupal for both the 6.x and 7.x branches of the FileField Sources module. The recommended mitigation strategy involves upgrading to versions 6.x-1.6 or 7.x-1.6, which contain proper input sanitization and output encoding mechanisms. Additionally, administrators should implement comprehensive monitoring of file upload activities and consider implementing additional security controls such as file type validation, content inspection, and regular security audits of uploaded files. Network-based intrusion detection systems should be configured to monitor for suspicious file upload patterns, and access controls should be reviewed to ensure that only necessary users have file upload capabilities. The vulnerability demonstrates the critical importance of input validation and output encoding in preventing XSS attacks, and serves as a reminder of the necessity for regular security updates and patch management procedures in content management systems.