CVE-2009-3306 in ClearSite
Summary
by MITRE
PHP remote file inclusion vulnerability in include/header.php in ClearSite 4.50 allows remote attackers to execute arbitrary PHP code via a URL in the cs_base_path parameter.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2009-3306 represents a critical remote file inclusion flaw in ClearSite version 4.50, specifically within the include/header.php component. This vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly restrict user-supplied data from being directly incorporated into file inclusion operations. The flaw manifests when the cs_base_path parameter receives a URL value that is subsequently processed by a vulnerable include statement, creating an avenue for malicious actors to inject and execute arbitrary PHP code on the target server. The vulnerability is classified under CWE-88 as improper neutralization of special elements used in an expression, specifically in the context of remote file inclusion attacks.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL and passes it as the cs_base_path parameter to the vulnerable application. The application processes this parameter without adequate validation, allowing the remote file inclusion to proceed. When the include/header.php script executes, it incorporates the attacker-controlled URL as a file path, effectively downloading and executing remote PHP code on the target system. This represents a classic remote code execution vector that enables attackers to gain full control over the affected server, potentially leading to data breaches, system compromise, and further lateral movement within the network infrastructure. The vulnerability aligns with ATT&CK technique T1190 for Exploit Public-Facing Application and T1059.007 for Command and Scripting Interpreter: PHP, demonstrating how attackers can leverage web application flaws to execute malicious code.
The operational impact of this vulnerability extends beyond immediate code execution capabilities to encompass comprehensive system compromise and data exfiltration risks. Organizations running ClearSite 4.50 are exposed to potential unauthorized access, where attackers can establish persistent backdoors, modify website content, steal sensitive data, or use the compromised server as a launching point for attacks against other systems. The vulnerability affects the application's core functionality by allowing attackers to bypass normal access controls and execute arbitrary commands with the privileges of the web server process. This risk is compounded by the fact that the vulnerability can be exploited without authentication, making it particularly dangerous for publicly accessible web applications. The flaw essentially undermines the fundamental security boundaries of the web application, allowing attackers to effectively control the server environment through a simple parameter manipulation.
Mitigation strategies for CVE-2009-3306 require immediate implementation of multiple defensive measures to protect against exploitation. Organizations should implement strict input validation and sanitization for all user-supplied parameters, particularly those used in file inclusion operations, ensuring that only predetermined, trusted values are accepted. The application code should be updated to use absolute paths instead of user-controllable variables in include statements, and the php.ini configuration should disable remote file inclusion features by setting allow_url_fopen and allow_url_include to off. Additionally, network-level protections including web application firewalls and intrusion detection systems should be deployed to monitor and block suspicious requests containing potentially malicious URLs. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other parts of the application, while system administrators should ensure that ClearSite is updated to a patched version that addresses this specific flaw. The remediation process should also include comprehensive logging and monitoring to detect any exploitation attempts, and security teams should establish incident response procedures to quickly address potential compromises.