CVE-2008-6103 in A4desk Flash Event Calendar
Summary
by MITRE
PHP remote file inclusion vulnerability in index.php in A4Desk Event Calendar, when magic_quotes_gpc is disabled, allows remote attackers to execute arbitrary PHP code via a URL in the v parameter.
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Analysis
by VulDB Data Team • 03/08/2025
The CVE-2008-6103 vulnerability represents a critical remote file inclusion flaw in the A4Desk Event Calendar application that exploits a fundamental PHP security mechanism. This vulnerability specifically targets the index.php script and leverages the absence of magic_quotes_gpc protection to enable remote code execution. The flaw operates through the v parameter which accepts user-supplied URLs, creating an attack vector that can be exploited by malicious actors to inject and execute arbitrary PHP code on the target server. The vulnerability's severity is amplified when the web server configuration disables magic_quotes_gpc, which normally provides basic protection against certain injection attacks by escaping special characters in user input.
The technical exploitation of this vulnerability follows a well-documented pattern that aligns with CWE-88, which describes improper neutralization of argument separators in a command or query. Attackers can craft malicious URLs containing PHP code within the v parameter, bypassing normal input validation mechanisms. When the application processes this parameter without proper sanitization, it includes and executes the remote file, effectively granting attackers a backdoor into the system. The vulnerability directly relates to CWE-94, which covers improper execution of code, as the application fails to validate or sanitize user input before incorporating it into dynamic code execution contexts. This flaw demonstrates a classic lack of input validation and output encoding that violates fundamental secure coding practices.
The operational impact of CVE-2008-6103 extends beyond simple code execution to encompass full system compromise and potential data breaches. Once exploited, attackers can establish persistent access through the included remote files, potentially using the compromised server for further attacks or as a staging ground for additional malicious activities. The vulnerability creates a pathway for attackers to escalate privileges, access sensitive data, modify application functionality, or use the compromised system for botnet activities. According to ATT&CK framework, this vulnerability maps to T1059.007 for execution through PHP and T1078 for valid accounts or credentials, as the attack may involve legitimate user accounts or system access. The compromised calendar application could serve as a stepping stone for attackers to move laterally within network environments, particularly if the server hosts other sensitive applications or data.
Mitigation strategies for this vulnerability require immediate implementation of multiple defensive layers. The primary recommendation involves enabling magic_quotes_gpc or implementing robust input validation and sanitization measures that prevent URL inclusion in parameters. Administrators should ensure that all user-supplied input undergoes proper validation before being processed, particularly when dealing with file inclusion operations. The application should be updated to use absolute paths and prevent dynamic inclusion of external resources. Additionally, implementing proper access controls and network segmentation can limit the potential damage from successful exploitation. Security monitoring should include detection of suspicious file inclusion patterns and unusual network traffic originating from the affected application. Organizations should also consider implementing web application firewalls to block malicious requests containing suspicious URL patterns. Regular security audits and vulnerability assessments should be conducted to identify similar flaws in other applications, as this vulnerability demonstrates a common pattern of insufficient input validation that affects numerous web applications across different platforms and technologies.