CVE-2003-0559 in phpforum
Summary
by MITRE
mainfile.php in phpforum 2 RC-1, and possibly earlier versions, allows remote attackers to execute arbitrary PHP code by modifying the MAIN_PATH parameter to reference a URL on a remote web server that contains the code.
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Analysis
by VulDB Data Team • 06/29/2021
This vulnerability exists in phpforum version 2 RC-1 and potentially earlier releases, representing a critical remote code execution flaw that allows attackers to inject and execute arbitrary PHP code on affected systems. The vulnerability stems from improper input validation and sanitization within the mainfile.php script where the MAIN_PATH parameter is directly used without adequate security controls. When an attacker manipulates this parameter to point to a remote URL containing malicious PHP code, the application blindly includes and executes the remote content, creating a dangerous attack vector that can lead to complete system compromise.
The technical implementation of this vulnerability leverages PHP's include or require functions that accept URL parameters, enabling what is known as a remote file inclusion attack. This flaw directly maps to CWE-88, which describes improper neutralization of special elements used in an expression, and CWE-94, which covers execution of externally supplied code. The vulnerability operates at the application layer and can be exploited through HTTP requests that manipulate the MAIN_PATH parameter, making it particularly dangerous as it requires no authentication or local access to the target system. Attackers can leverage this weakness to execute commands, access sensitive data, modify system files, or establish persistent backdoors.
The operational impact of CVE-2003-0559 is severe and multifaceted, as it provides attackers with complete control over affected web servers running vulnerable versions of phpforum. Successful exploitation can result in data breaches, system infiltration, and potential lateral movement within network environments. The vulnerability's remote nature means that attackers can exploit it from anywhere on the internet, making it particularly dangerous for organizations with exposed web applications. This weakness can also serve as a stepping stone for more sophisticated attacks, as attackers can use the compromised system as a pivot point to target other systems within the network.
Organizations should implement immediate mitigations including updating to the latest version of phpforum that addresses this vulnerability, implementing proper input validation and sanitization for all user-supplied parameters, and configuring web servers to disable remote file inclusion capabilities. Network segmentation and firewall rules should be enforced to limit access to vulnerable applications, while application-level security measures such as using allowlists for file inclusion paths and implementing proper parameter validation should be deployed. According to ATT&CK framework, this vulnerability corresponds to T1190 for exploit public-facing application and T1059 for command and scripting interpreter, highlighting the need for comprehensive defensive measures including web application firewalls, regular security audits, and proper input validation across all application components.