CVE-2021-46013 in Free School Management Software
Summary
by MITRE • 01/18/2022
An unrestricted file upload vulnerability exists in Sourcecodester Free school management software 1.0. An attacker can leverage this vulnerability to enable remote code execution on the affected web server. Once a php webshell containing "" gets uploaded it is saved into /uploads/exam_question/ directory, and is accessible by all users.
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Analysis
by VulDB Data Team • 01/20/2022
The CVE-2021-46013 vulnerability represents a critical security flaw in the Sourcecodester Free school management software version 1.0 that exposes organizations to severe remote code execution risks. This vulnerability stems from inadequate input validation and file upload restrictions within the web application's file handling mechanisms. The flaw allows malicious actors to bypass security controls and upload arbitrary files to the server, creating a persistent backdoor for unauthorized access and system compromise.
The technical implementation of this vulnerability involves unrestricted file upload functionality that fails to properly validate file types, extensions, or content before storing uploaded files on the web server. The affected application permits file uploads to the /uploads/exam_question/ directory without adequate sanitization measures, enabling attackers to submit malicious PHP webshells that can execute arbitrary commands on the target system. This weakness directly maps to CWE-434 Unrestricted Upload of File with Dangerous Type, which specifically addresses the dangers of allowing unrestricted file uploads that can lead to remote code execution. The vulnerability creates a pathway for attackers to establish persistent access and escalate privileges within the compromised environment.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it enables full remote code execution capabilities that can be leveraged for data exfiltration, system reconnaissance, and lateral movement within network environments. Once an attacker successfully uploads a PHP webshell, the malicious payload becomes immediately accessible to all users of the application, eliminating the need for additional authentication or privilege escalation. This vulnerability poses significant risks to educational institutions that rely on the software for managing sensitive student and administrative data, potentially exposing confidential information and disrupting critical educational services. The persistent nature of the uploaded webshell allows attackers to maintain long-term access to the compromised system, making it particularly dangerous for organizations without proper monitoring and incident response procedures.
Mitigation strategies for CVE-2021-46013 should focus on implementing comprehensive file upload validation controls and restricting file execution permissions within the affected directory structure. Organizations must enforce strict file type validation, implement proper content verification mechanisms, and ensure that uploaded files are stored outside the web root directory to prevent direct execution. Security measures should include implementing proper access controls, regular security audits, and monitoring for unauthorized file uploads. The vulnerability demonstrates the importance of adhering to security best practices such as those outlined in the OWASP Top Ten and MITRE ATT&CK framework, particularly in addressing the threat of malicious file uploads and the execution of unauthorized code within web applications. Regular patching and vulnerability management processes are essential to prevent exploitation of this type of vulnerability and maintain the integrity of school management systems.