CVE-2003-1252 in S8Forum
Summary
by MITRE
register.php in S8Forum 3.0 allows remote attackers to execute arbitrary PHP commands by creating a user whose name ends in a .php extension and entering the desired commands into the E-mail field, which creates a web-accessible .php file that can be called by the attacker, as demonstrated using a "system($cmd)" E-mail address with a "any_name.php" username.
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Analysis
by VulDB Data Team • 01/13/2025
This vulnerability exists in S8Forum 3.0's register.php script and represents a critical arbitrary code execution flaw that allows remote attackers to gain unauthorized access to the affected system. The vulnerability stems from improper input validation and sanitization of user registration data, specifically the username and email fields. When a malicious user registers with a username ending in .php extension and places PHP code within the email field, the application fails to properly validate or sanitize these inputs before storing them in the database.
The technical flaw manifests as a directory traversal and code injection vulnerability where the application creates web-accessible files based on user input without adequate security checks. When the malicious username ends with .php, the system treats it as a valid file extension and creates a corresponding PHP file in the web root directory. This creates a persistent backdoor that can be accessed through direct web requests, allowing attackers to execute arbitrary commands on the server with the privileges of the web application.
The operational impact of this vulnerability is severe as it provides attackers with complete control over the affected server. Once exploited, attackers can execute system commands, access sensitive data, modify or delete files, and potentially use the compromised server as a launching point for further attacks against other systems. The vulnerability is particularly dangerous because it allows attackers to create persistent backdoors that remain active even after the initial exploitation, making detection and remediation more challenging. This type of vulnerability aligns with CWE-94, which describes "Improper Control of Generation of Code" and represents a classic example of a code injection vulnerability.
The attack vector is straightforward and requires minimal technical expertise to exploit, making it particularly dangerous in environments where proper input validation and access controls are not implemented. This vulnerability demonstrates the critical importance of validating user inputs and implementing proper sanitization of all data before processing or storing it in the system. Organizations should implement strict input validation, sanitize all user-supplied data, and avoid creating executable files based on user input without proper security checks.
Mitigation strategies should include implementing proper input validation and sanitization for all user registration fields, particularly username and email fields. The system should reject any username containing file extensions or special characters that could be used to create executable files. Additionally, proper access controls and file permissions should be implemented to prevent unauthorized file creation and execution. Organizations should also consider implementing web application firewalls and regular security monitoring to detect and prevent such attacks. This vulnerability highlights the need for secure coding practices and adherence to security standards such as those outlined in the OWASP Top Ten and MITRE ATT&CK framework, specifically addressing techniques related to command injection and privilege escalation.