CVE-2011-4306 in Moodle
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in course/editsection.html in Moodle 1.9.x before 1.9.14 allows remote authenticated users to inject arbitrary web script or HTML via crafted data.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2011-4306 represents a critical cross-site scripting flaw within the Moodle learning management system version 1.9.x prior to 1.9.14. This vulnerability specifically affects the course/editsection.html component, which is responsible for managing course section editing functionalities within the Moodle platform. The flaw arises from insufficient input validation and output sanitization mechanisms that fail to properly filter malicious content submitted by authenticated users. The vulnerability classification aligns with CWE-79, which defines improper neutralization of input during web page generation, commonly known as cross-site scripting. This weakness enables attackers to execute arbitrary web scripts or HTML code within the context of other users' browsers, potentially compromising the integrity and confidentiality of user data within the educational environment.
The technical exploitation of this vulnerability requires an authenticated user with sufficient privileges to access the course editing interface, typically a teacher or administrator role within Moodle. Attackers can craft malicious data inputs containing script tags or HTML elements that are then stored within the Moodle database and subsequently rendered in the course section editing page without proper sanitization. When other users access the affected page, their browsers execute the injected malicious code, which can lead to various harmful outcomes including session hijacking, data theft, redirection to malicious websites, or modification of course content. The vulnerability demonstrates a classic XSS flaw where user-supplied data flows directly into the web page output without adequate encoding or filtering mechanisms.
The operational impact of CVE-2011-4306 extends beyond simple data corruption, potentially enabling sophisticated attacks within educational institutions that rely on Moodle for their learning management needs. Attackers could leverage this vulnerability to steal user credentials, manipulate course materials, or establish persistent backdoors within the learning environment. The authenticated nature of the attack reduces the attack surface complexity but increases the potential damage since attackers already possess legitimate user credentials. Organizations using vulnerable Moodle versions face significant risks including unauthorized access to sensitive educational data, compromise of student privacy, and potential disruption of educational services. The vulnerability also aligns with ATT&CK technique T1059.007, which involves the use of scripting languages for execution, and T1566.001, covering spearphishing with embedded attachments or links, as attackers could use this flaw to deliver malicious payloads through compromised course content.
Mitigation strategies for this vulnerability center on immediate patching and implementation of robust input validation measures. Organizations must upgrade to Moodle 1.9.14 or later versions where this vulnerability has been addressed through proper input sanitization and output encoding mechanisms. Additionally, administrators should implement Content Security Policy headers to limit script execution capabilities within the Moodle environment, and consider implementing Web Application Firewalls to detect and block suspicious input patterns. Regular security audits and input validation testing should be conducted to identify similar vulnerabilities in other components of the Moodle platform. The remediation process should also include user education regarding the risks of clicking suspicious links or submitting untrusted content within the learning management system, as social engineering remains a critical factor in successful exploitation of such vulnerabilities.