CVE-2006-5637 in Faq Administrator
Summary
by MITRE
PHP remote file inclusion vulnerability in faq_reply.php in Faq Administrator 2.1b allows remote attackers to execute arbitrary PHP code via a URL in the email parameter.
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability identified as CVE-2006-5637 represents a critical remote file inclusion flaw within the Faq Administrator 2.1b web application, specifically affecting the faq_reply.php script. This vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly filter user-supplied data before incorporating it into dynamic file inclusion operations. The flaw manifests when the application accepts an email parameter that is directly used in a file inclusion context without proper security controls, creating an avenue for malicious actors to inject arbitrary PHP code through remote URLs.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL and passes it as the email parameter to the vulnerable faq_reply.php endpoint. The application processes this input without sufficient validation, allowing the remote file inclusion to proceed and execute the malicious code hosted on the attacker-controlled server. This type of vulnerability falls under the CWE-88 category of Improper Neutralization of Argument Delimiters in a Command, specifically relating to command injection and file inclusion attacks. The vulnerability is classified as a remote code execution threat that can be leveraged without authentication, making it particularly dangerous in web application environments where user input is processed without proper sanitization.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected web server's functionality. An attacker can leverage this vulnerability to upload additional malicious files, establish backdoors, perform data exfiltration, or use the compromised server as a pivot point for attacking other systems within the network. The vulnerability affects the confidentiality, integrity, and availability of the web application and underlying infrastructure, potentially leading to full system compromise. This type of attack aligns with the tactics described in the MITRE ATT&CK framework under the T1059.007 technique for Command and Scripting Interpreter: PowerShell, where attackers leverage web application vulnerabilities to execute malicious code remotely.
Mitigation strategies for this vulnerability require immediate implementation of input validation and sanitization measures, including the removal of dynamic file inclusion patterns that rely on user-supplied parameters. Organizations should implement proper parameter validation that rejects suspicious URL formats and ensures that all inputs are properly escaped before being used in file operations. The recommended approach involves using allowlists of trusted values and implementing secure coding practices that prevent the direct use of user input in include or require statements. Additionally, deploying web application firewalls and implementing proper access controls can provide additional layers of defense. The vulnerability highlights the importance of following secure coding guidelines and the principle of least privilege in web application development, where all user inputs should be treated as potentially malicious until properly validated and sanitized.