CVE-2013-4502 in FileField Sources
Summary
by MITRE
The FileField Sources module 6.x-1.x before 6.x-1.9 and 7.x-1.x before 7.x-1.9 for Drupal does not properly check file permissions, which allows remote authenticated users to read arbitrary files by attaching a file.
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Analysis
by VulDB Data Team • 03/03/2018
The FileField Sources module for Drupal represents a critical security vulnerability classified as CVE-2013-4502 that affects versions 6.x-1.x before 6.x-1.9 and 7.x-1.x before 7.x-1.9. This vulnerability resides within the module's improper handling of file permissions, creating a significant security gap that can be exploited by remote authenticated attackers. The flaw specifically manifests when users attach files to content, allowing malicious actors to bypass normal file access controls and read arbitrary files from the server filesystem.
The technical implementation of this vulnerability stems from inadequate input validation and permission checking mechanisms within the file attachment functionality. When authenticated users submit files through the FileField Sources module, the system fails to properly verify whether the user has appropriate permissions to access the target files. This weakness enables attackers to manipulate file paths and access sensitive data that should normally be restricted. The vulnerability operates at the application layer and can be exploited through standard web interface interactions without requiring special privileges beyond basic user authentication.
From an operational impact perspective, this vulnerability poses severe risks to Drupal-based systems as it allows attackers to access potentially sensitive files including configuration files, database credentials, user information, and other system resources. The attack vector is particularly concerning because it requires only authenticated access, meaning that any user with valid credentials can potentially exploit this flaw. This creates a scenario where compromised user accounts can lead to broader system compromise, as attackers can gather intelligence about the system configuration and identify additional attack vectors. The vulnerability also impacts data confidentiality and can result in compliance violations when sensitive information is exposed.
Security professionals should consider this vulnerability in relation to CWE-22, which addresses improper limitation of a pathname to a restricted directory, and CWE-284, which covers improper access control. The attack pattern aligns with ATT&CK technique T1083, which focuses on file and directory discovery, and T1078, which addresses valid accounts for lateral movement. Organizations should prioritize immediate patching of affected Drupal installations and implement network monitoring to detect potential exploitation attempts. Additional mitigations include restricting file attachment permissions, implementing web application firewalls, and conducting regular security audits of third-party modules to ensure proper access controls are maintained throughout the application stack.