CVE-2006-4977 in PhpQuiz
Summary
by MITRE
Multiple unrestricted file upload vulnerabilities in (1) back/upload_img.php and (2) admin/upload_img.php in Walter Beschmout PhpQuiz 1.2 and earlier allow remote attackers to upload arbitrary PHP code to the phpquiz/img_quiz folder via the (a) upload, (b) ok_update, (c) image, and (d) path parameters, possibly requiring directory traversal sequences in the path parameter.
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Analysis
by VulDB Data Team • 07/20/2024
The CVE-2006-4977 vulnerability represents a critical security flaw in Walter Beschmout PhpQuiz version 1.2 and earlier, exposing multiple unrestricted file upload points that enable remote code execution. This vulnerability affects two specific files within the application's codebase: back/upload_img.php and admin/upload_img.php, both of which handle image upload functionality without proper validation mechanisms. The flaw resides in the application's failure to implement adequate input sanitization and file type verification, creating a pathway for malicious actors to bypass security controls and upload potentially harmful files to the server.
The technical implementation of this vulnerability stems from the application's lack of proper file validation processes during the upload procedure. Attackers can exploit the upload functionality through four distinct parameters: upload, ok_update, image, and path, with the path parameter potentially requiring directory traversal sequences to navigate to the target phpquiz/img_quiz folder. This weakness allows unauthorized users to upload arbitrary PHP code directly to the web server, effectively bypassing the application's intended security boundaries and creating a persistent backdoor for malicious activities. The vulnerability's design flaw directly aligns with CWE-434, which specifically addresses the insecure upload of code or files, and represents a classic example of improper input validation in web applications.
The operational impact of this vulnerability extends far beyond simple unauthorized file uploads, as it provides attackers with the capability to execute arbitrary code on the target server. Once successfully exploited, attackers can gain full control over the web application's execution environment, potentially leading to complete system compromise, data exfiltration, or the establishment of persistent access points. The vulnerability's location within the admin section of the application means that successful exploitation could provide attackers with administrative privileges, enabling them to manipulate the application's functionality, access sensitive data, or modify critical system components. This threat vector significantly impacts the confidentiality, integrity, and availability of the affected system, as demonstrated by the ATT&CK technique T1505.003 for "Upload File to Execute" and T1059.007 for "Command and Scripting Interpreter: PowerShell."
Mitigation strategies for CVE-2006-4977 require immediate implementation of multiple defensive measures to protect against unauthorized file uploads. Organizations must implement strict file type validation by checking file extensions against a whitelist of allowed formats, enforce proper file content verification through MIME type checking, and ensure that uploaded files are stored in directories that are not directly accessible via web requests. The application should also implement proper access controls and authentication mechanisms to prevent unauthorized access to upload functions, while also implementing directory traversal protection to prevent attackers from navigating to restricted directories. Additionally, the system should employ proper file naming conventions to prevent overwriting of existing files and maintain comprehensive logging of all upload activities for security monitoring purposes. These defensive measures directly address the underlying security weaknesses that make the vulnerability exploitable and align with industry best practices for secure file upload implementations as outlined in OWASP Top Ten and NIST cybersecurity guidelines.