CVE-2021-25200 in Learning Management System
Summary
by MITRE • 07/30/2021
Arbitrary file upload vulnerability in SourceCodester Learning Management System v 1.0 allows attackers to execute arbitrary code, via the file upload to \lms\student_avatar.php.
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Analysis
by VulDB Data Team • 08/05/2021
The CVE-2021-25200 vulnerability represents a critical arbitrary file upload flaw within the SourceCodester Learning Management System version 1.0 that exposes organizations to remote code execution risks. This vulnerability specifically targets the student_avatar.php endpoint which processes file uploads without adequate validation mechanisms. The flaw allows attackers to bypass security controls and upload malicious files that can subsequently be executed on the target system, potentially leading to complete system compromise and unauthorized access to sensitive educational data.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the file upload handler. The lms/student_avatar.php script fails to properly verify file extensions, content types, or file contents before storing uploaded files. This weakness creates an attack surface where malicious actors can upload files with potentially dangerous extensions such as .php, .asp, or .jsp that will be executed by the web server. The vulnerability directly maps to CWE-434 which describes insecure file upload handling, where applications accept files from untrusted sources without proper validation. Attackers can leverage this weakness by crafting malicious payloads that exploit the lack of proper file type restrictions and execute arbitrary commands on the vulnerable system.
The operational impact of CVE-2021-25200 extends beyond simple code execution to encompass complete system compromise and data breaches. Organizations utilizing this learning management system face significant risks including unauthorized access to student records, course materials, and administrative data. The vulnerability enables attackers to establish persistent backdoors, escalate privileges, and potentially move laterally within network environments. This risk is particularly severe in educational institutions where sensitive personal information and academic data are stored. The attack vector aligns with ATT&CK technique T1190 which describes exploiting vulnerabilities in software applications to gain initial access. Additionally, the vulnerability can be exploited to establish command and control channels, making it a valuable tool for threat actors seeking long-term access to target environments.
Mitigation strategies for CVE-2021-25200 should focus on immediate patching of the vulnerable software version and implementation of robust file upload validation controls. Organizations must ensure that all file uploads are validated against a strict whitelist of approved extensions and that uploaded files are stored outside the web root directory. The system should implement proper content type checking, file size restrictions, and mandatory file format verification. Network segmentation and monitoring should be enhanced to detect suspicious file upload activities. Security patches should be applied immediately to upgrade to a non-vulnerable version of the SourceCodester LMS. Organizations should also implement web application firewalls and conduct regular security assessments to identify similar vulnerabilities in other applications. The remediation process should include thorough code review of file handling mechanisms and implementation of secure coding practices that prevent similar issues from occurring in future development cycles.