CVE-2014-9059 in Moodle
Summary
by MITRE
lib/setup.php in Moodle through 2.4.11, 2.5.x before 2.5.9, 2.6.x before 2.6.6, and 2.7.x before 2.7.3 does not provide charset information in HTTP headers, which might allow remote attackers to conduct cross-site scripting (XSS) attacks via UTF-7 characters during interaction with AJAX scripts.
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Analysis
by VulDB Data Team • 04/04/2022
The vulnerability identified as CVE-2014-9059 affects Moodle versions through 2.4.11, 2.5.x before 2.5.9, 2.6.x before 2.6.6, and 2.7.x before 2.7.3, specifically within the lib/setup.php file. This issue represents a critical security flaw that stems from the absence of proper character set information in HTTP headers, creating a pathway for remote attackers to execute cross-site scripting attacks through UTF-7 character manipulation during AJAX interactions. The vulnerability operates at the intersection of web application security and HTTP protocol compliance, where the lack of explicit charset declaration creates ambiguity in how browsers interpret incoming content.
The technical flaw manifests in the improper handling of character encoding within Moodle's core setup mechanism. When the lib/setup.php script fails to include charset information in HTTP headers, it leaves browsers to make assumptions about character encoding, particularly when processing AJAX requests that may contain UTF-7 encoded characters. This encoding ambiguity enables attackers to craft malicious payloads that exploit the browser's automatic character set detection mechanisms. The vulnerability specifically targets the interaction between the web application and AJAX scripts, where user input is processed without proper sanitization or encoding validation. This weakness allows attackers to inject malicious JavaScript code through UTF-7 character sequences that browsers may incorrectly interpret as regular text, subsequently executing the injected code within the victim's browser context.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it provides attackers with a method to compromise user sessions and potentially gain unauthorized access to sensitive educational data. The attack vector is particularly concerning because it leverages legitimate AJAX functionality within Moodle's architecture, making it difficult to detect through standard security monitoring. The vulnerability affects users who interact with Moodle's AJAX-based features, which are fundamental components of the learning management system's user interface. Attackers can exploit this flaw to execute malicious scripts in the context of authenticated users, potentially leading to session hijacking, data theft, or unauthorized modifications to course content. The widespread use of AJAX in modern web applications makes this vulnerability particularly dangerous as it can be exploited across various Moodle functionalities including user management, course administration, and content delivery systems.
The security implications align with CWE-1004 which addresses insecure default configurations, and the attack pattern corresponds to the ATT&CK technique T1211 - Exploitation for Defense Evasion. Organizations using affected Moodle versions face significant risk of unauthorized access to educational platforms, potentially compromising student data, instructor credentials, and institutional information systems. The vulnerability demonstrates how seemingly minor configuration issues in HTTP headers can create substantial security risks in web applications. Security professionals should note that this vulnerability underscores the importance of proper HTTP header configuration and character set handling in preventing browser-based attacks. The flaw also highlights the necessity of robust input validation and encoding practices in web applications, particularly those handling user-generated content through AJAX interfaces. Organizations should prioritize immediate patching of affected Moodle installations to prevent exploitation and maintain the integrity of their educational platforms.
The remediation approach requires updating to patched versions of Moodle that properly implement charset headers in HTTP responses. System administrators should also implement proper input validation mechanisms and ensure that all web applications include appropriate Content-Type headers with explicit character set declarations. Additionally, organizations should conduct security audits of their web applications to identify similar configuration issues that might create similar vulnerabilities. The incident serves as a reminder of the critical importance of maintaining up-to-date software versions and implementing comprehensive security practices in educational technology environments. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues that could compromise the security of learning management systems.