CVE-2011-4282 in Moodle
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the course-tags functionality in tag/coursetags_more.php in Moodle 2.0.x before 2.0.2 allow remote attackers to inject arbitrary web script or HTML via the (1) sort or (2) show parameter.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2011-4282 represents a critical cross-site scripting flaw within Moodle's course tags functionality, specifically affecting versions 2.0.x prior to 2.0.2. This issue resides in the tag/coursetags_more.php file where user input is improperly sanitized, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of authenticated users' browsers. The vulnerability manifests through two distinct parameter injection points: the sort parameter and the show parameter, both of which are processed without adequate input validation or output encoding mechanisms.
The technical nature of this vulnerability aligns with CWE-79, which defines cross-site scripting as a weakness where untrusted data is incorporated into web page content without proper validation or encoding. Attackers can exploit this flaw by crafting malicious payloads that target these specific parameters, allowing them to inject JavaScript code or HTML content that executes when other users view the affected course tags page. The impact extends beyond simple script execution as it can potentially enable session hijacking, credential theft, or the redirection of users to malicious websites. The vulnerability's exploitation requires minimal privileges since it operates within the context of legitimate Moodle functionality, making it particularly dangerous as it can be leveraged by attackers with basic access to the platform.
From an operational perspective, this vulnerability poses significant risks to Moodle installations as it can be exploited by remote attackers without requiring authentication to the system. The affected functionality is part of Moodle's core course management features, making it frequently accessed by users and administrators alike. When exploited, the XSS attack can lead to unauthorized access to user sessions, data exfiltration, and potential lateral movement within the educational platform's ecosystem. The vulnerability's impact is amplified by the fact that Moodle is widely deployed in educational institutions where users may have elevated privileges or access to sensitive academic data. This makes the platform an attractive target for attackers seeking to compromise educational environments and potentially gain access to confidential student or institutional information.
The mitigation strategy for CVE-2011-4282 involves immediate patching to version 2.0.2 or later, which includes proper input validation and output encoding mechanisms for the affected parameters. Organizations should implement comprehensive input sanitization measures that validate all user-supplied data against expected formats and encode output data appropriately to prevent script injection. Network monitoring should be enhanced to detect suspicious parameter patterns that may indicate exploitation attempts, while web application firewalls can be configured to block known malicious payloads targeting these specific vulnerabilities. Regular security assessments and vulnerability scanning should be conducted to identify similar issues within other components of the Moodle platform, as this vulnerability demonstrates the importance of proper input handling in web applications. Additionally, user education regarding the risks of clicking suspicious links or visiting untrusted websites can help reduce the potential impact of successful exploitation attempts, although the primary defense remains the implementation of proper security controls within the application code itself.