CVE-2008-7029 in AliBoard
Summary
by MITRE
Unrestricted file upload vulnerability in usercp.php in AlilG Application AliBoard Beta allows remote authenticated users to execute arbitrary code by uploading a file with an executable extension as an avatar, then accessing it via a direct request to the file in uploads/avatars/.
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Analysis
by VulDB Data Team • 11/22/2018
The vulnerability described in CVE-2008-7029 represents a critical security flaw in the AliBoard Beta application's user control panel component. This unrestricted file upload vulnerability exists in the usercp.php file, which handles user account management functions including avatar customization. The flaw allows authenticated users to bypass normal file validation mechanisms and upload malicious files with executable extensions such as .php, .asp, or .jsp directly to the server's avatar upload directory. The vulnerability stems from inadequate input validation and sanitization processes that fail to properly verify file types, content, or extensions before storing uploaded files on the server filesystem.
The technical implementation of this vulnerability exploits the lack of proper file type checking and the absence of secure file handling practices within the application's avatar upload functionality. When users upload files through the usercp.php interface, the application does not perform sufficient validation to ensure that uploaded files conform to expected formats or contain malicious code. This weakness creates a path for attackers who are already authenticated to the system to upload shell scripts or other executable code that can be executed by the web server. The vulnerability is particularly dangerous because it allows attackers to upload files with extensions that are typically executable by the web server, such as .php, .asp, or .jsp, which can then be executed directly through HTTP requests to the uploaded files in the uploads/avatars/ directory.
The operational impact of this vulnerability is severe and multifaceted. An authenticated attacker can gain arbitrary code execution capabilities on the affected server, potentially leading to complete system compromise. Once an attacker successfully uploads a malicious file, they can execute commands on the server with the privileges of the web application user, which typically has access to the application's database and file system. This vulnerability can result in data theft, system infiltration, service disruption, and potential lateral movement within the network. The attack vector is relatively straightforward, requiring only authenticated access to the application and knowledge of the upload directory structure, making it accessible to attackers who have gained user credentials through other means such as phishing or credential theft.
From a cybersecurity perspective, this vulnerability aligns with CWE-434, which describes unrestricted file upload or file upload without proper validation, and represents a classic example of insufficient input validation and improper file handling. The flaw also maps to several ATT&CK techniques including T1190 for exploitation of vulnerabilities, T1059 for command and scripting interpreter usage, and T1078 for valid accounts. The vulnerability demonstrates poor security practices in web application development, particularly regarding the principle of least privilege and secure file handling. Organizations affected by this vulnerability should immediately implement mitigations including restricting file upload capabilities, implementing proper file type validation, using random file names, storing uploaded files outside the web root, and implementing proper access controls on the upload directory.
The recommended mitigation strategies include implementing strict file type validation that checks both file extensions and MIME types, using random or UUID-based filenames to prevent predictable file paths, storing uploaded files outside the web-accessible directory structure, implementing proper access controls and permissions on upload directories, and regularly auditing file upload functionality for security vulnerabilities. Additionally, organizations should consider implementing web application firewalls and intrusion detection systems to monitor for suspicious file upload activities. The vulnerability also underscores the importance of regular security assessments and penetration testing to identify and remediate similar flaws in application code. This particular vulnerability highlights the critical need for secure coding practices and proper input validation in all web application components that handle user-supplied data, as even authenticated users with legitimate access can be exploited to gain unauthorized system access through poorly secured file upload mechanisms.