CVE-2014-3543 in Moodle
Summary
by MITRE
mod/imscp/locallib.php in Moodle through 2.3.11, 2.4.x before 2.4.11, 2.5.x before 2.5.7, 2.6.x before 2.6.4, and 2.7.x before 2.7.1 allows remote attackers to read arbitrary files via a package with a manifest file containing an XML external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue affecting IMSCP resources and the IMSCC format.
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Analysis
by VulDB Data Team • 06/04/2017
The vulnerability identified as CVE-2014-3543 represents a critical XML External Entity (XXE) flaw within Moodle's IMS Content Package (IMSCP) handling mechanism. This security weakness exists in the mod/imscp/locallib.php file and affects multiple versions of the Moodle learning management system including 2.3.11 and earlier, 2.4.x versions before 2.4.11, 2.5.x versions before 2.5.7, 2.6.x versions before 2.6.4, and 2.7.x versions before 2.7.1. The vulnerability stems from insufficient input validation and sanitization when processing IMS Content Package files that utilize the IMS Common Cartridge (IMSCC) format, which is a standard for packaging educational content in learning management systems.
The technical exploitation of this XXE vulnerability occurs when a malicious actor uploads a specially crafted package containing a manifest file with XML external entity declarations. When Moodle processes this package, it parses the XML content without proper sanitization, allowing an attacker to reference external entities that can be used to access local files on the server. This flaw enables remote attackers to perform unauthorized file reads, potentially exposing sensitive information such as configuration files, database credentials, or other system resources that are accessible to the web server process. The vulnerability specifically affects the IMSCP module's handling of XML content, where the system fails to properly validate or sanitize XML entities before processing, creating a direct path for attackers to leverage the XML parsing functionality for information disclosure.
The operational impact of this vulnerability is significant as it allows remote attackers to bypass normal access controls and retrieve arbitrary files from the server filesystem. This represents a severe information disclosure risk that could lead to credential theft, system compromise, or exposure of sensitive educational data. The vulnerability is particularly dangerous because it requires no authentication to exploit, making it a high-severity threat that could be leveraged by anyone with access to upload packages to the Moodle system. Attackers could potentially access database configuration files, user credentials stored in configuration files, or other sensitive system information that would otherwise be protected by normal file access controls, directly violating the principle of least privilege and enabling further attacks on the system infrastructure.
Organizations using affected Moodle versions should immediately apply the security patches released by Moodle to address this vulnerability. The mitigation strategy involves updating to the patched versions of Moodle where the XML parsing logic has been hardened to prevent external entity resolution and to properly sanitize input from IMS Content Package manifest files. System administrators should also implement additional security measures including restricting file upload permissions, implementing network segmentation to limit access to sensitive files, and monitoring for suspicious file upload activities. From a compliance perspective, this vulnerability aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and represents a violation of the principle of input validation as outlined in the OWASP Top Ten. The ATT&CK framework categorizes this as a privilege escalation technique through information gathering, where attackers can use this vulnerability to discover system information that can be leveraged for subsequent attacks, making it a critical component in the reconnaissance phase of security breaches.