CVE-2013-4341 in Moodle
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Moodle through 2.2.11, 2.3.x before 2.3.9, 2.4.x before 2.4.6, and 2.5.x before 2.5.2 allow remote attackers to inject arbitrary web script or HTML via a crafted blog link within an RSS feed.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability identified as CVE-2013-4341 represents a critical cross-site scripting flaw affecting multiple versions of the Moodle learning management system. This vulnerability resides in the RSS feed processing functionality where the application fails to properly sanitize user input when handling blog links within RSS feeds. The issue affects Moodle versions up to 2.2.11, 2.3.x versions prior to 2.3.9, 2.4.x versions before 2.4.6, and 2.5.x versions before 2.5.2, creating a widespread impact across the Moodle ecosystem. The vulnerability specifically targets the RSS feed parser component that processes external blog links, making it particularly dangerous in educational environments where users frequently interact with external content sources. The flaw allows remote attackers to inject malicious web scripts or HTML code through carefully crafted blog links that are then processed and displayed within the Moodle interface, potentially compromising user sessions and system integrity.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the RSS feed processing module. When Moodle encounters an RSS feed containing a blog link with malicious content, the system does not properly escape or sanitize the URL before rendering it in the user interface. This failure to implement proper HTML escaping techniques creates a pathway for attackers to execute arbitrary JavaScript code within the context of a user's browser session. The vulnerability manifests when users view RSS feeds containing malicious blog links, as the system renders these links without sufficient security controls to prevent script execution. This represents a classic case of improper neutralization of input during web application development, which aligns with CWE-79 - Improper Neutralization of Input During Web Page Generation. The flaw exists at the intersection of data processing and output rendering, where external data flows through the application without adequate security measures to prevent malicious code injection.
The operational impact of CVE-2013-4341 extends beyond simple script injection, potentially enabling attackers to perform session hijacking, steal user credentials, or redirect users to malicious websites. In educational environments, this vulnerability poses significant risks as Moodle platforms typically contain sensitive user data including personal information, grades, and course materials. Attackers could exploit this vulnerability to gain unauthorized access to student and instructor accounts, potentially compromising entire institutional learning management systems. The attack vector is particularly concerning because it leverages legitimate RSS feed functionality that users expect to work safely, making the attack less suspicious and more likely to succeed. The vulnerability also aligns with ATT&CK technique T1566.001 - Phishing via Service, where attackers use compromised services to deliver malicious payloads to unsuspecting users. Organizations using affected Moodle versions face potential data breaches, privacy violations, and compliance issues that could result in regulatory penalties and reputational damage.
Organizations should immediately implement mitigations including updating to patched versions of Moodle that address this vulnerability, implementing proper input validation for RSS feed processing, and deploying web application firewalls to monitor and filter malicious content. The recommended remediation strategy involves upgrading to Moodle versions 2.3.9, 2.4.6, or 2.5.2 respectively, which contain the necessary security patches. Additional protective measures include implementing content security policies to prevent script execution, conducting regular security audits of RSS feed integrations, and providing user education about the risks of clicking external links. Network administrators should also consider implementing monitoring solutions that can detect and alert on suspicious RSS feed content. The vulnerability demonstrates the importance of comprehensive security testing in web applications, particularly in educational platforms that handle sensitive user data and require robust security controls to maintain trust and compliance with privacy regulations.