Moodle Cross-Site Scripting Scanner

Moodle is a popular learning management system used by educational institutions, organizations, and individuals to create and manage online courses and learning activities. It provides features such as course creation, management, and deployment, facilitating seamless teacher-student interactions. Organizations benefit from Moodle's flexible and scalable platform, allowing customization and integration with third-party applications. Moodle is used widely across the globe, fostering e-learning by providing collaborative learning environments. Its open-source nature allows developers to contribute to and enhance its functionalities continuously. The system is crucial for managing educational content, assessments, and learner progress effectively.

Cross-Site Scripting (XSS) is a security vulnerability that allows an attacker to inject malicious scripts into content from trusted websites. This vulnerability can lead to various harmful consequences, such as the theft of sensitive information, session hijacking, or spreading malware. XSS attacks exploit the trust that users have in a specific website, using it as a vector to execute unauthorized scripts in a user's browser. Such vulnerabilities are serious as they can compromise the integrity and confidentiality of user interactions and data. In Moodle, the XSS vulnerability specifically affects a parameter that can be manipulated to execute unwanted scripts. Addressing this type of vulnerability is essential to ensure the secure use of web applications.

The technical details of the XSS vulnerability in Moodle involve the manipulation of the redirect_uri parameter. By injecting a malicious JavaScript payload, an attacker can cause this script to execute in a victim's browser session. The vulnerability is prevalent in several versions of Moodle before specific patches were applied. The vulnerability primarily affects the HTTP request methodology within Moodle's authentication process. It has been discovered that certain HTML elements and headers can be exploited to carry out XSS attacks. Mitigation requires careful input validation and strict content security policies to prevent such exploits.

If exploited, the Cross-Site Scripting vulnerability in Moodle can lead to unauthorized actions performed on behalf of a user, data theft, or alteration without user awareness. Malicious entities can gain access to sensitive information, disrupting the educational processes by manipulating grades, assignments, or personal data. Furthermore, an XSS attack can facilitate unauthorized access to the broader network, distributing attacks across connected users. Such exploitation might undermine trust and cause significant damage to the educational institution's reputation.

REFERENCES

• https://twitter.com/JacksonHHax/status/1391367064154042377
• https://nvd.nist.gov/vuln/detail/CVE-2021-32478