CVE-2021-3943 is a critical vulnerability affecting Moodle, specifically versions 3.11 to 3.11.3, 3.10 to 3.10.7, and 3.9 to 3.9.10, as well as earlier unsupported versions. This vulnerability allows a remote code execution risk when restoring backup files, potentially giving attackers the ability to execute arbitrary code on the server.
The severity of this vulnerability is rated as critical, with a CVSS score of 9.8. The high score indicates a significant risk to organizations, especially due to the potential for remote code execution, which can be exploited without user interaction and without requiring elevated privileges. Attackers may leverage this flaw to gain unauthorized access to sensitive data or control over the affected systems.
Given the nature of this vulnerability, organizations should prioritize patching immediately. The risk to organizations includes exposure to remote attacks, potential data breaches, and the overall compromise of system integrity and availability.
As of now, there is known exploit information available, but organizations should remain vigilant and apply the necessary patches as they become available.
Vulnerability Details
The flaw identified in Moodle poses a remote code execution risk when restoring backup files. This vulnerability primarily affects Moodle versions 3.11 (up to 3.11.3), 3.10 (up to 3.10.7), and 3.9 (up to 3.9.10), as well as earlier unsupported versions. The vulnerability has been classified under CWE-20, which relates to improper input validation.
The CVSS score of 9.8 indicates a critical severity level, with high impacts on confidentiality, integrity, and availability. The vulnerability was published on November 22, 2021, and its status is currently marked as modified.
Technical Analysis
The root cause of this vulnerability stems from improper input validation when restoring backup files within Moodle. Attackers can exploit this weakness through a network attack vector, which has a low attack complexity. No privileges are required to exploit this vulnerability, nor is user interaction necessary.
The impacts of this vulnerability are severe, resulting in potential high confidentiality, integrity, and availability impacts. Attackers gaining access could manipulate data, disrupt services, or exfiltrate sensitive information.
Risk & Impact Analysis
Organizations utilizing affected versions of Moodle face significant risks due to this vulnerability. The potential for remote code execution exposes systems to unauthorized access and control, leading to data breaches and potential compliance violations. The blast radius could include not only the Moodle instances but also any data or systems interconnected with it.
Given the critical nature of this vulnerability, organizations must assess their deployment and prioritize remediation based on the CVSS score and the known exploitation status. This vulnerability necessitates immediate attention to avoid severe consequences.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of Moodle include 3.11 (up to 3.11.3), 3.10 (up to 3.10.7), and 3.9 (up to 3.9.10). Organizations should ensure they are running the latest patched versions to mitigate this vulnerability.
Mitigation & Remediation
Organizations should apply the available patches immediately to remediate this vulnerability. If patches are unavailable, consider implementing workarounds such as restricting access to backup restoration functionality. Organizations may also benefit from configuration hardening and network controls to limit exposure.
For continuous validation of security effectiveness, organizations should engage in continuous penetration testing to identify similar weaknesses.
Detection Guidance
Organizations should monitor logs for any indicators of unauthorized backup restorations or unexpected changes in system behavior. Behavioral anomalies and unusual access patterns should be carefully scrutinized. Additionally, network signatures that may indicate exploitation attempts should be established.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-3943 lies in its reflection of the broader trends in web application security, particularly concerning improper input validation. Security teams should take this opportunity to evaluate their application security posture and implement best practices to prevent similar vulnerabilities.
Organizations should also consider proactive measures such as engaging in penetration testing methodology and adopting a vulnerability management program to enhance their security framework. By understanding how similar vulnerabilities can arise, organizations can fortify their defenses.
Finally, the incident underscores the importance of continuous education and training within development teams, highlighting the need for secure coding practices. Implementing best practices in development can significantly mitigate risks associated with such vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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