CVE-2009-1663 in Answer
Summary
by MITRE
Unrestricted file upload vulnerability in myaccount.php in Easy Scripts Answer and Question Script allows remote attackers to execute arbitrary code by uploading a file with an executable extension, then accessing it via a direct request to the file in the uploads/[username] directory.
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Analysis
by VulDB Data Team • 11/29/2024
The CVE-2009-1663 vulnerability represents a critical unrestricted file upload flaw in the Easy Scripts Answer and Question Script version 1.0, specifically within the myaccount.php component. This vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly restrict file types permitted for upload. The flaw allows remote attackers to bypass security measures by uploading malicious files with executable extensions such as .php, .asp, or .jsp directly to the server's upload directory structure.
The technical implementation of this vulnerability leverages the absence of proper file extension validation and content type checking within the file upload functionality. When users upload files through the myaccount.php interface, the application does not adequately verify the file extensions or MIME types, enabling attackers to submit files with potentially harmful code. The uploaded files are subsequently stored in the uploads/[username] directory structure, where they become accessible via direct HTTP requests to the file paths. This design flaw creates a path traversal and code execution vector that directly violates security principles outlined in the OWASP Top Ten and CWE-434.
The operational impact of this vulnerability is severe and multifaceted, encompassing both immediate and long-term security implications. Remote attackers can execute arbitrary code on the target server with the privileges of the web application, potentially leading to full system compromise. The vulnerability enables attackers to establish persistent backdoors, deploy web shells, or execute malicious payloads that can be used for data exfiltration, lateral movement, or further exploitation within the network. This weakness directly maps to ATT&CK technique T1190 (Exploit Public-Facing Application) and T1059 (Command and Scripting Interpreter) within the MITRE ATT&CK framework.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive file upload restrictions and validation mechanisms. Organizations should enforce strict file extension filtering, implement proper MIME type checking, and utilize random or secure file naming conventions to prevent predictable file paths. The application must validate file content rather than relying solely on extensions, employ proper directory permissions, and implement web application firewalls to detect and block malicious upload attempts. Additionally, regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components, as this flaw aligns with CWE-434 which specifically addresses insecure file upload scenarios. The vulnerability demonstrates the critical importance of implementing defense-in-depth strategies and proper input validation to prevent unauthorized code execution in web applications.