CVE-2008-6619 in ClassSystem
Summary
by MITRE
Unrestricted file upload vulnerability in class/ApplyDB.php in ClassSystem 2.3 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 class/UploadHomepage/.
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Analysis
by VulDB Data Team • 04/30/2025
The vulnerability identified as CVE-2008-6619 represents a critical unrestricted file upload flaw within the ClassSystem 2.3 web application framework. This vulnerability exists in the ApplyDB.php file located in the class directory, which fails to properly validate or sanitize file uploads submitted by remote attackers. The flaw allows malicious actors to bypass normal file upload restrictions by uploading executable files with extensions that would typically be blocked, thereby creating a pathway for remote code execution. The vulnerability specifically impacts the class/UploadHomepage/ directory where uploaded files are stored and made accessible via direct web requests.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the file upload mechanism. When users submit files through the application's interface, the system does not properly verify file extensions, MIME types, or file content against a whitelist of allowed formats. This allows attackers to upload files with executable extensions such as .php, .asp, .jsp, or other server-side scripting languages that can be executed directly by the web server. The vulnerability is particularly dangerous because it does not require authentication or special privileges to exploit, making it accessible to any remote attacker who can interact with the application's upload functionality.
The operational impact of CVE-2008-6619 is severe and multifaceted, representing a significant risk to web application security and system integrity. Successful exploitation enables attackers to execute arbitrary code on the target server with the privileges of the web application user, which typically corresponds to the web server's execution context. This can lead to complete system compromise, data exfiltration, lateral movement within the network, and potential establishment of persistent backdoors. The vulnerability also exposes the application to various attack vectors including but not limited to web shell deployment, database compromise, and privilege escalation attacks. According to the CWE database, this vulnerability maps to CWE-434, which specifically addresses Unrestricted Upload of File with Dangerous Type, a well-documented weakness that has been exploited in numerous real-world attacks.
The attack surface for this vulnerability is particularly concerning given the nature of web applications that allow user-uploaded content. Attackers can leverage this flaw to upload malicious files that execute commands on the server, potentially leading to full system compromise. The direct accessibility of uploaded files through the class/UploadHomepage/ directory means that once a malicious file is uploaded, it can be executed immediately by accessing the file directly through a web browser or HTTP client. This vulnerability aligns with several MITRE ATT&CK techniques including T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, which are commonly used in post-compromise activities.
Mitigation strategies for CVE-2008-6619 require a multi-layered approach to address both the immediate vulnerability and prevent similar issues in the future. The most effective immediate solution involves implementing strict file type validation and sanitization, including maintaining a whitelist of allowed file extensions and MIME types, and rejecting any uploads that do not conform to these restrictions. Additionally, uploaded files should be stored outside the web root directory, and proper file permissions should be enforced to prevent direct execution of uploaded content. The application should also implement proper content validation to ensure that uploaded files do not contain malicious code or executable content. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for suspicious upload patterns and potentially malicious file access attempts. Regular security audits and code reviews should be conducted to identify and remediate similar vulnerabilities in other parts of the application. This vulnerability demonstrates the critical importance of proper input validation and the principle of least privilege in web application security, as outlined in various security frameworks including the OWASP Top Ten and NIST Cybersecurity Framework.