CVE-2021-20279 : Exploit Details and Defense Strategies

This article provides an in-depth analysis of CVE-2021-20657, a vulnerability found in Moodle that could lead to a stored XSS risk.

Understanding CVE-2021-20279

In this section, we will delve into the details of the CVE-2021-20657 vulnerability.

What is CVE-2021-20279?

The vulnerability in moodle before versions 3.10.2, 3.9.5, 3.8.8, and 3.5.17 arises due to inadequate sanitization of the ID number user profile field, posing a risk of stored cross-site scripting (XSS) attack.

The Impact of CVE-2021-20279

The vulnerability could allow an attacker to execute malicious scripts in users' browsers, potentially leading to unauthorized access, data theft, or further exploitation of the affected system.

Technical Details of CVE-2021-20279

Let's explore the technical aspects of CVE-2021-20279 to understand the vulnerability further.

Vulnerability Description

The insufficient sanitization of the ID number user profile field in Moodle versions prior to 3.10.2, 3.9.5, 3.8.8, and 3.5.17 enables an attacker to store and execute arbitrary scripts on the target system.

Affected Systems and Versions

Moodle instances running versions before 3.10.2, 3.9.5, 3.8.8, and 3.5.17 are susceptible to this vulnerability. Users are urged to update to the patched versions to mitigate the risk.

Exploitation Mechanism

Attackers can exploit this vulnerability by injecting malicious scripts into the ID number user profile field, which, when executed, can compromise user data and system integrity.

Mitigation and Prevention

To safeguard systems from CVE-2021-20279, it is crucial to take immediate action and implement long-term security measures.

Immediate Steps to Take

Upgrade Moodle to the patched versions (3.10.2, 3.9.5, 3.8.8, or 3.5.17) to eliminate the vulnerability.
Educate users about the risks of executing scripts from untrusted sources.

Long-Term Security Practices

Regularly monitor and audit the user input fields to ensure proper sanitization and validation.
Stay informed about security advisories and promptly apply patches and updates.

Patching and Updates

Developers and system administrators should prioritize applying security patches released by Moodle to address CVE-2021-20279 and enhance system security.