CVE-2021-36399 : Exploit Details and Defense Strategies

This article provides detailed information about CVE-2021-36399, a vulnerability found in Moodle that poses a stored XSS risk. Learn about the impact, technical details, and mitigation strategies for this CVE.

Understanding CVE-2021-36399

CVE-2021-36399 is a vulnerability identified in Moodle related to ID numbers displayed in the quiz override screens that required additional sanitizing to prevent a stored XSS risk.

What is CVE-2021-36399?

CVE-2021-36399 is a security flaw in Moodle, an online learning platform, where unsanitized ID numbers displayed in quiz override screens can lead to stored Cross-Site Scripting (XSS) attacks.

The Impact of CVE-2021-36399

This vulnerability could allow attackers to inject malicious scripts into Moodle, potentially compromising user data, executing unauthorized commands, or defacing the platform.

Technical Details of CVE-2021-36399

Understanding the specifics of the vulnerability, affected systems, and how it can be exploited is crucial for effective mitigation.

Vulnerability Description

The vulnerability stems from the lack of proper sanitization of ID numbers displayed in the quiz override screens, enabling malicious actors to inject harmful scripts.

Affected Systems and Versions

Moodle version 3.11 has been confirmed to be affected by CVE-2021-36399, potentially putting users of this version at risk.

Exploitation Mechanism

By manipulating ID numbers in the quiz override screens, threat actors can inject malicious scripts that persist within Moodle, leading to XSS attacks.

Mitigation and Prevention

Protecting systems from CVE-2021-36399 requires immediate actions and long-term security practices to safeguard against similar vulnerabilities in the future.

Immediate Steps to Take

Users are advised to update Moodle to a patched version, apply security fixes, and sanitize input fields to prevent XSS attacks.

Long-Term Security Practices

Implement strict input validation mechanisms, conduct regular security audits, and educate users on safe online practices to enhance overall platform security.

Patching and Updates

Stay informed about security updates from Moodle, promptly apply patches, and monitor security advisories to address potential vulnerabilities effectively.