Moodle Jsmol Cross-Site Scripting Scanner

Moodle is a widely-used open-source learning management system that facilitates the creation of educational courses. Institutions and teachers utilize Moodle to offer online learning experiences and manage student engagement by posting resources, forums, quizzes, and more. The platform is versatile and can be customized with numerous plugins to serve diverse learning styles and objectives. The Jsmol plugin in Moodle provides molecular visualization capabilities, enhancing educational content for chemistry and biology courses. This plugin allows educators to incorporate interactive, 3D molecular models in their instructional material. Jsmol's integration in Moodle ensures dynamically rendered visual content, elevating the academic value of online science modules.

Cross-Site Scripting (XSS) is a vulnerability that enables attackers to inject malicious scripts into web applications. This vulnerability can be exploited by crafting a web request to target users with scripts that execute in their browsers, potentially stealing sensitive information such as authentication cookies. XSS can compromise the integrity of a user session, facilitating further attacks on the affected account or network. By intercepting user input that is reflected in the web interface without proper sanitization, attackers can execute arbitrary code. The risk inherent to XSS includes hijacked user accounts, potential data exposure, and unauthorized actions carried out in the user's context within the vulnerable application. Vigilance against XSS is critical for maintaining a secure web application's integrity and user privacy.

The identified XSS vulnerability in the Moodle Jsmol plugin pertains to a GET request endpoint that mishandles user input. Specifically, the issue exists in the 'jsmol.php' script managed within the '/filter/jmol/js/jsmol/php/' directory, where input passed to a parameter fails to be sanitized. Attackers can exploit this by crafting payloads containing malicious JavaScript, which the server returns unsanitized in the HTTP response. When unsuspecting users visit a crafted URL, this injected script executes in their browser due to the inclusion of HTML tags within parameters. The ability to inject scripts is confirmed by the resulting page displaying an alert box, a classic indicator of XSS indicating successful execution.

When exploited, this XSS vulnerability can have several detrimental effects. Malicious entities can gain access to user sessions by intercepting cookies, allowing unauthorized actions within the user's account. Additionally, attackers can manipulate the application's appearance or functionality, leading to misinformation or further security risks like distributing malware. This vulnerability may extend to broader network implications, where users unintentionally propagate the malicious script within forums or communications. The violation of user privacy and potential data leaks pose significant reputational damage to organizations using Moodle, highlighting the need for prompt and effective mitigation measures.

REFERENCES

• https://www.dionach.com/blog/moodle-jmol-plugin-multiple-vulnerabilities/