CVE-2005-4800 in YaPIG
Summary
by MITRE
Direct static code injection vulnerability in Yet Another PHP Image Gallery (YaPIG) 0.95b and earlier allows remote authenticated administrators to inject arbitrary PHP code via the TestGallery parameter in a mod_info action to modify_gallery.php, which inserts the code into guid_info.php. NOTE: this issue is easier to exploit due to a separate CSRF vulnerability.
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Analysis
by VulDB Data Team • 07/16/2018
The CVE-2005-4800 vulnerability represents a critical direct static code injection flaw within the Yet Another PHP Image Gallery version 0.95b and earlier. This vulnerability specifically targets authenticated administrator users who possess the ability to access the gallery modification interface. The flaw exists within the modify_gallery.php script where the TestGallery parameter in the mod_info action is processed without adequate input sanitization or validation. When an authenticated administrator submits malicious code through this parameter, the system directly incorporates the injected code into the guid_info.php file, creating a persistent backdoor mechanism that can be executed during subsequent gallery operations.
The technical nature of this vulnerability aligns with CWE-94, which describes the weakness of allowing code injection in applications that execute dynamically generated code. The flaw operates as a direct code injection vector where user-supplied input flows directly into the execution context without proper escaping or sanitization. This creates an environment where attackers can execute arbitrary PHP code with the privileges of the web application, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it leverages the administrative privileges of authenticated users, eliminating the need for additional authentication bypass techniques.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to the compromised system. Once the malicious PHP code is injected into guid_info.php, it remains active and executable whenever the gallery functionality is accessed, creating a long-term foothold for attackers. The vulnerability's exploitation is further facilitated by a separate CSRF vulnerability that makes it easier for attackers to deliver malicious payloads to authenticated users without their knowledge. This combination creates a particularly dangerous attack scenario where an attacker can leverage a simple CSRF vector to gain administrative access and then execute code injection attacks.
The security implications of this vulnerability demonstrate the critical importance of input validation and output encoding in web applications. The flaw violates fundamental security principles by failing to implement proper sanitization of user inputs before they are processed and stored within the application's codebase. Organizations affected by this vulnerability should immediately implement patching procedures to upgrade to versions of YaPIG that address this injection vulnerability. Additionally, network segmentation and monitoring should be enhanced to detect anomalous code execution patterns that might indicate successful exploitation. The vulnerability also highlights the necessity of implementing proper access controls and privilege separation to limit the damage that authenticated users can cause when compromised.
This vulnerability serves as a prime example of why defense-in-depth strategies are essential in modern web application security. The combination of code injection with CSRF vulnerabilities creates a multi-layered attack surface that can be exploited even by attackers with limited initial access. The remediation process should include not only applying the necessary security patches but also conducting thorough security audits of the application's input handling mechanisms. Security teams should also implement web application firewalls and runtime application self-protection mechanisms to detect and prevent similar injection attacks. The vulnerability underscores the importance of regular security assessments and the need for developers to follow secure coding practices that prevent injection flaws from occurring in the first place.