CVE-2023-5550 in Moodle
Summary
by MITRE • 11/09/2023
In a shared hosting environment that has been misconfigured to allow access to other users' content, a Moodle user who also has direct access to the web server outside of the Moodle webroot could utilise a local file include to achieve remote code execution.
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Analysis
by VulDB Data Team • 11/11/2023
This vulnerability exists within Moodle's shared hosting environment where misconfigurations allow unauthorized access to other users' content. The flaw stems from inadequate access controls and permission settings that enable a compromised user to exploit a local file inclusion vulnerability. When a user possesses both Moodle account access and direct server access outside the webroot, they can manipulate file inclusion mechanisms to execute arbitrary code remotely. The vulnerability represents a critical security weakness in web application architecture where proper isolation between user environments has been breached.
The technical implementation of this vulnerability relies on the exploitation of local file inclusion (LFI) mechanisms within Moodle's codebase. Attackers can leverage their dual access privileges to manipulate file paths and include malicious files that execute arbitrary commands on the server. This occurs because the shared hosting environment lacks proper sandboxing controls that would normally prevent one user from accessing another user's files or system resources. The vulnerability operates through the manipulation of file inclusion parameters that should normally be restricted to legitimate system paths, allowing attackers to bypass normal access controls.
The operational impact of this vulnerability is severe and far-reaching within shared hosting environments. Successful exploitation can result in complete system compromise, data theft, privilege escalation, and potential lateral movement to other systems within the hosting infrastructure. Attackers can use the executed code to establish persistent backdoors, exfiltrate sensitive user data including personal information and credentials, and potentially use the compromised server as a launch point for attacks on other systems. The vulnerability essentially eliminates the security boundaries that should exist between different users in a shared hosting environment, creating a single point of failure that can affect all users on the same server.
Mitigation strategies should focus on implementing proper access controls and isolation mechanisms within shared hosting environments. Organizations must ensure that proper file permissions and access controls are enforced to prevent unauthorized file access between users. The implementation of proper web application firewalls and input validation controls can help detect and prevent exploitation attempts. Regular security audits and proper configuration management should be implemented to ensure that hosting environments maintain appropriate security boundaries. Additionally, organizations should consider migrating to more secure hosting solutions or implementing additional security layers such as containerization or virtualization to isolate user environments effectively. This vulnerability highlights the importance of adhering to security best practices and proper system hardening as outlined in industry standards such as those referenced in the CWE database under categories related to improper access control and insecure file handling. The attack vector aligns with techniques described in the MITRE ATT&CK framework under initial access and privilege escalation tactics, emphasizing the need for comprehensive security controls at multiple layers of the infrastructure.