CVE-2005-3926 in GuppY
Summary
by MITRE
Direct static code injection vulnerability in error.php in GuppY 4.5.9 and earlier, when register_globals is disabled, allows remote attackers to execute arbitrary PHP code via the _SERVER[REMOTE_ADDR] parameter, which is injected into a .inc script that is later included by the main script.
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Analysis
by VulDB Data Team • 07/22/2025
The vulnerability described in CVE-2005-3926 represents a critical direct static code injection flaw within the GuppY content management system version 4.5.9 and earlier. This vulnerability specifically targets the error.php component and exploits a fundamental weakness in how user-supplied input is handled within the application's error handling mechanism. The flaw occurs when the PHP configuration parameter register_globals is disabled, which is considered a security best practice in modern web applications. However, this security measure inadvertently creates a window of opportunity for attackers to manipulate the application's behavior through carefully crafted input parameters.
The technical execution of this vulnerability relies on the manipulation of the _SERVER[REMOTE_ADDR] parameter which is typically used to capture the IP address of incoming requests. In the vulnerable GuppY versions, this parameter is directly incorporated into a .inc script that gets included by the main application script during execution. This inclusion process creates a scenario where attacker-controlled data becomes part of the executable code flow, allowing for arbitrary PHP code execution. The vulnerability is classified under CWE-94, which specifically addresses "Improper Control of Generation of Code ('Code Injection')" and falls within the broader category of code injection attacks that have been consistently identified as one of the most dangerous security flaws in web applications.
The operational impact of this vulnerability extends far beyond simple code execution, as it provides attackers with complete control over the affected server environment. Once successful, an attacker can execute malicious PHP code with the privileges of the web server process, potentially leading to full system compromise, data exfiltration, or the installation of backdoors. The vulnerability is particularly concerning because it operates without requiring authentication and can be exploited through simple HTTP requests. This makes it an attractive target for automated exploitation tools and increases the attack surface significantly. According to ATT&CK framework, this vulnerability maps to T1059.007, which covers "Command and Scripting Interpreter: PHP," and represents a classic example of how improper input validation and dynamic code execution can create persistent security weaknesses.
Mitigation strategies for this vulnerability require immediate action from system administrators, including upgrading to a patched version of GuppY 4.5.10 or later, which addresses the code injection flaw through proper input sanitization and parameter handling. Organizations should also implement proper input validation mechanisms that prevent user-supplied data from being directly incorporated into executable code paths. The fix typically involves ensuring that all user input is properly escaped or sanitized before being processed, particularly in contexts where dynamic includes or code generation occurs. Additionally, implementing a web application firewall that monitors for suspicious parameter patterns and maintaining comprehensive logging of all error handling activities can provide early detection capabilities. Security teams should also consider implementing runtime protections such as PHP's disable_functions directive to limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of following secure coding practices and demonstrates how seemingly benign configuration settings like register_globals can create unexpected security implications when combined with improper input handling techniques.