CVE-2020-24949 in php-fusion
Summary
by MITRE
Privilege escalation in PHP-Fusion 9.03.50 downloads/downloads.php allows an authenticated user (not admin) to send a crafted request to the server and perform remote command execution (RCE).
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2020-24949 represents a critical privilege escalation flaw within PHP-Fusion version 9.03.50 specifically affecting the downloads/downloads.php component. This issue enables authenticated users who do not possess administrative privileges to exploit a weakness that ultimately allows them to execute arbitrary commands on the target server. The vulnerability stems from insufficient input validation and improper access controls within the downloads module, creating a pathway for malicious users to bypass normal security restrictions and gain elevated system access. The flaw exists in the way the application processes user-supplied data within the download functionality, where crafted requests can be manipulated to trigger unintended behavior.
The technical implementation of this vulnerability involves a combination of improper input sanitization and insecure direct object references within the downloads.php script. Attackers can construct specially formatted requests that exploit the application's handling of file download parameters, allowing them to inject malicious code that gets executed with the privileges of the web server process. This type of vulnerability falls under the category of command injection attacks and aligns with CWE-77 and CWE-94 classifications, representing both command injection and code execution flaws. The vulnerability demonstrates a clear breakdown in the principle of least privilege, where user authentication levels should prevent arbitrary code execution regardless of access rights.
Operationally, the impact of this vulnerability extends far beyond simple privilege escalation as it provides attackers with full remote command execution capabilities on the compromised server. An authenticated user can leverage this vulnerability to execute system commands, potentially leading to complete server compromise, data exfiltration, and further network infiltration. The vulnerability affects organizations running PHP-Fusion 9.03.50 installations where the downloads module is enabled, making it particularly concerning for content management systems that rely heavily on user-generated content and file sharing functionality. This flaw can be exploited from any location where an attacker has valid user credentials, making it a significant concern for applications with large user bases or those that do not properly monitor user activity.
Mitigation strategies for CVE-2020-24949 should focus on immediate patching of the affected PHP-Fusion version to the latest stable release that addresses the privilege escalation and command execution flaws. Organizations should implement proper input validation and output encoding mechanisms to prevent malicious data from being processed within the application's download functionality. Network segmentation and monitoring should be enhanced to detect suspicious requests that attempt to exploit this vulnerability, particularly focusing on unusual patterns in download parameter handling. The implementation of web application firewalls and security monitoring tools can help detect and block malicious requests before they reach the vulnerable code paths. Additionally, administrators should review user permissions and implement proper access controls to limit what authenticated users can do within the application, ensuring that even compromised user accounts cannot escalate privileges to system-level access. This vulnerability demonstrates the critical importance of maintaining up-to-date software and implementing proper security controls to prevent unauthorized code execution in web applications.