CVE-2006-6217 in Mermaid Module
Summary
by MITRE
PHP remote file inclusion vulnerability in formdisp.php in the Mermaid 1.2 module for PHP-Nuke allows remote attackers to execute arbitrary PHP code via a URL in the module_name parameter.
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Analysis
by VulDB Data Team • 09/28/2017
The CVE-2006-6217 vulnerability represents a critical remote file inclusion flaw in the Mermaid 1.2 module for PHP-Nuke, demonstrating a fundamental security weakness in web application input validation and resource handling. This vulnerability specifically affects the formdisp.php script within the Mermaid module, where user-supplied input is directly incorporated into file inclusion operations without proper sanitization or validation. The flaw occurs when the module_name parameter is processed, allowing malicious actors to inject arbitrary URLs that get executed as PHP code on the target server.
This vulnerability falls under the CWE-98 weakness category, which describes improper input validation in the context of remote file inclusion attacks. The technical implementation of this flaw exploits the lack of proper parameter validation in the PHP-Nuke module architecture, where the application fails to distinguish between legitimate module names and malicious URLs. Attackers can leverage this by crafting specially formatted URLs in the module_name parameter, which are then passed to PHP's include or require functions, effectively executing remote code on the vulnerable server. The vulnerability's severity is amplified by the fact that it operates at the core level of module execution within PHP-Nuke, providing attackers with extensive control over the affected system.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to gain complete control over the vulnerable web server. According to ATT&CK framework techniques, this vulnerability maps to T1059.007 for command and scripting interpreter usage and T1505.003 for server-side include attacks. An attacker can leverage this vulnerability to establish persistent access, deploy backdoors, exfiltrate sensitive data, or use the compromised server as a launchpad for further attacks within the network. The vulnerability's remote nature means that exploitation can occur from anywhere on the internet without requiring local system access, making it particularly dangerous for web applications that are publicly accessible.
Mitigation strategies for CVE-2006-6217 should focus on immediate patching of the affected Mermaid module, as the original vulnerability was resolved through proper input validation and sanitization. Organizations should implement strict parameter validation in all user input handling, particularly for file inclusion operations, and disable remote file inclusion capabilities in PHP configuration. The principle of least privilege should be enforced by restricting PHP's ability to include remote files through settings like allow_url_include and allow_url_fopen. Additionally, web application firewalls and intrusion detection systems should be configured to monitor for suspicious URL patterns in module_name parameters, while regular security audits and code reviews should be conducted to identify similar vulnerabilities in other modules. Network segmentation and access controls can provide additional defense-in-depth measures to limit the potential impact of successful exploitation attempts.