CVE-2013-4524 in Moodle
Summary
by MITRE
Directory traversal vulnerability in repository/filesystem/lib.php in Moodle through 2.2.11, 2.3.x before 2.3.10, 2.4.x before 2.4.7, and 2.5.x before 2.5.3 allows remote authenticated users to read arbitrary files via a .. (dot dot) in a path.
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Analysis
by VulDB Data Team • 06/15/2017
The CVE-2013-4524 vulnerability represents a critical directory traversal flaw within Moodle's file system handling mechanism that affected multiple versions of the popular learning management system. This vulnerability exists in the repository/filesystem/lib.php component and enables authenticated remote attackers to access arbitrary files on the server by manipulating file paths through directory traversal sequences. The flaw specifically exploits how the system processes path navigation elements, allowing attackers to bypass normal file access controls and retrieve sensitive information from the underlying file system.
The technical implementation of this vulnerability stems from inadequate input validation and path sanitization within Moodle's file handling routines. When authenticated users submit file paths containing .. (dot dot) sequences, the system fails to properly sanitize these inputs before processing them, enabling attackers to navigate upward through the directory structure and access files outside of the intended scope. This weakness aligns with CWE-22, which categorizes directory traversal vulnerabilities as improper input validation issues. The vulnerability affects Moodle versions through 2.2.11, 2.3.x before 2.3.10, 2.4.x before 2.4.7, and 2.5.x before 2.5.3, indicating a widespread impact across multiple release branches.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with access to sensitive system files, configuration data, and potentially user information stored on the server. An authenticated attacker could exploit this flaw to access database configuration files, system logs, user credentials, and other confidential data that should remain protected within the application's intended file access boundaries. This vulnerability directly supports tactics described in the MITRE ATT&CK framework under T1083 (File and Directory Discovery) and T1566 (Phishing) as attackers could leverage this weakness to obtain credentials and sensitive information that could be used for further compromise.
Organizations running affected Moodle versions face significant security risks, as this vulnerability allows attackers to escalate their privileges through unauthorized file access. The impact is particularly concerning given that Moodle is widely deployed in educational institutions and corporate training environments where sensitive personal and academic data is stored. The vulnerability's exploitation requires only authenticated access, making it accessible to users with legitimate credentials who may have access to the system. This makes it a particularly dangerous flaw in environments where user access controls may be less stringent or where credentials could be compromised through social engineering or other attack vectors. Mitigation strategies should include immediate patching of affected versions, implementation of proper input validation, and enforcement of strict file access controls within the Moodle configuration.