CVE-2008-2216 in Project-based Calendaring System
Summary
by MITRE
Unrestricted file upload vulnerability in src/yopy_upload.php in Project-Based Calendaring System (PBCS) 0.7.1 allows remote authenticated users to upload arbitrary files to tmp/uploads.
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Analysis
by VulDB Data Team • 10/21/2024
The CVE-2008-2216 vulnerability represents a critical security flaw in the Project-Based Calendaring System version 0.7.1, specifically within the file upload functionality located in src/yopy_upload.php. This vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly restrict file types and content during the upload process. The flaw enables authenticated attackers to bypass security controls and upload arbitrary files to the tmp/uploads directory, creating a significant attack surface that can be exploited for various malicious purposes. The vulnerability is particularly concerning because it requires only authentication, meaning that any user with valid credentials can potentially exploit this weakness without requiring additional privileges or complex attack vectors.
The technical implementation of this vulnerability falls under CWE-434, which specifically addresses unrestricted upload of file with dangerous type, a classification that directly applies to this scenario where the system fails to validate file extensions, content types, or file contents before storing uploaded files. The flaw occurs because the yopy_upload.php script does not perform adequate checks to verify that uploaded files conform to expected file types or contain malicious code. Attackers can leverage this vulnerability by uploading web shells, malicious scripts, or other harmful file types that can be executed within the web application's context. The tmp/uploads directory serves as a temporary storage location that is typically not properly secured, making it an ideal target for attackers seeking to establish persistent access or execute arbitrary code on the server.
The operational impact of CVE-2008-2216 extends beyond simple unauthorized file uploads, as it creates multiple attack vectors for compromising the entire system. Once an attacker successfully uploads malicious files, they can potentially execute code with the privileges of the web server process, leading to complete system compromise. The vulnerability can be exploited to establish backdoors, exfiltrate sensitive data, or use the compromised system as a launching point for further attacks against internal networks. This type of vulnerability is particularly dangerous in environments where the web application has elevated privileges or access to sensitive databases and system resources. The attack surface is further expanded because the tmp directory is often not properly secured with access controls, allowing uploaded files to be directly executed or accessed by unauthorized parties.
Mitigation strategies for this vulnerability should focus on implementing comprehensive file upload validation mechanisms that align with industry best practices and security standards. Organizations should implement strict file type validation by checking file extensions against a whitelist of approved types, examining file headers and content signatures, and implementing proper file name sanitization to prevent path traversal attacks. The system should enforce proper access controls on the tmp/uploads directory, ensuring that uploaded files are stored in a location that cannot be directly executed by the web server. Additionally, implementing the principle of least privilege for file upload functionality and regularly monitoring upload directories for suspicious activity can significantly reduce the risk of exploitation. Security measures should also include regular vulnerability assessments and penetration testing to identify similar weaknesses in other components of the application stack. The ATT&CK framework categorizes this type of vulnerability under T1190 - Exploit Public-Facing Application, highlighting the importance of securing all application interfaces and implementing robust input validation controls to prevent such attacks from succeeding.