CVE-2007-1604 in w-Agora
Summary
by MITRE
Multiple unrestricted file upload vulnerabilities in w-Agora (Web-Agora) allow remote attackers to upload and execute arbitrary PHP code (1) via a forum message with an attached file, which is stored under forums/hello/hello/notes/ or (2) by using browse_avatar.php to upload a file with a double extension, as demonstrated by .php.jpg.
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Analysis
by VulDB Data Team • 08/27/2018
The vulnerability CVE-2007-1604 represents a critical security flaw in w-Agora, a web-based discussion forum application that affects multiple versions of the software. This issue stems from inadequate input validation and file handling mechanisms within the application's file upload functionality. The vulnerability manifests in two distinct attack vectors that collectively enable remote attackers to execute arbitrary code on the target system. The first vector involves uploading malicious files through forum messages where attachments are stored in the forums/hello/hello/notes/ directory structure. The second vector exploits the browse_avatar.php component to upload files with double extensions such as .php.jpg, which bypasses typical file type validation checks.
The technical root cause of this vulnerability aligns with CWE-434, which describes unrestricted file upload flaws that occur when applications allow users to upload files without proper validation of file types, content, or storage locations. The vulnerability demonstrates a classic lack of proper file extension filtering and content verification mechanisms, allowing attackers to upload PHP files that can be executed by the web server. When attackers upload files with double extensions like .php.jpg, the web server may interpret the file based on the final extension rather than the actual file content, creating a path for code execution. This particular weakness enables attackers to bypass security controls that might only check for common dangerous file extensions such as .php, .asp, or .jsp.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected web server. Successful exploitation allows remote code execution, which can lead to data theft, system compromise, and potential lateral movement within the network. Attackers can upload web shells, backdoors, or other malicious payloads that persist on the server and can be used for extended unauthorized access. The vulnerability affects the confidentiality, integrity, and availability of the web application and underlying infrastructure, potentially enabling attackers to establish persistent access, exfiltrate sensitive information, or use the compromised server as a launch point for further attacks. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1190 for Web Shell and T1059 for Command and Scripting Interpreter, demonstrating how attackers can leverage such flaws to gain persistent access to target systems.
Mitigation strategies for this vulnerability require immediate implementation of comprehensive file upload restrictions and validation mechanisms. Organizations should implement strict file type validation that checks both file extensions and MIME types, while also verifying the actual content of uploaded files through proper file signature analysis. The application should enforce a whitelist approach for acceptable file types rather than relying on blacklists that can be easily bypassed. Additionally, uploaded files should be stored in non-executable directories and should be renamed to prevent the execution of malicious code. Implementing proper access controls and regular security audits of file upload functionality can help detect and prevent similar vulnerabilities in the future. The remediation process must include thorough code review to ensure that all file upload components properly validate user input and that the application follows secure coding practices as outlined in industry standards such as OWASP Top 10 and NIST guidelines for secure software development.