CVE-2006-3989 in Shoutbox
Summary
by MITRE
PHP remote file inclusion vulnerability in index.php in Knusperleicht Shoutbox 4.4 and earlier allows remote attackers to execute arbitrary PHP code via a URL in the sb_include_path parameter.
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Analysis
by VulDB Data Team • 07/11/2024
The vulnerability identified as CVE-2006-3989 represents a critical remote file inclusion flaw affecting the Knusperleicht Shoutbox version 4.4 and earlier. This security weakness resides within the index.php script of the affected software, where user-supplied input is improperly validated and processed. The vulnerability specifically targets the sb_include_path parameter which is used to determine which files should be included and executed within the application context. Attackers can exploit this weakness by supplying a malicious URL as the value for the sb_include_path parameter, thereby enabling arbitrary code execution on the vulnerable server. This type of vulnerability falls under the category of CWE-88, which describes improper neutralization of special elements used in an expression, and more specifically aligns with CWE-94, which covers improper execution of code through code injection. The attack vector operates through the principle of remote code execution, where an attacker can inject and execute malicious PHP code without requiring authentication or local access to the system.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected web server running the vulnerable software. Once successfully exploited, adversaries can upload additional malicious files, establish persistent backdoors, access sensitive data, and potentially use the compromised server as a launch point for further attacks within the network. The vulnerability's remote nature means that attackers do not need physical access to the system or knowledge of internal network structures to exploit it, making it particularly dangerous in production environments. According to ATT&CK framework, this vulnerability maps to T1059.007 for execution through PHP and T1190 for exploitation of remote services. The affected environment becomes vulnerable to command and control operations, data exfiltration, and lateral movement attacks, as the attacker essentially gains a foothold with the privileges of the web server process.
Mitigation strategies for CVE-2006-3989 require immediate action to address the root cause of the vulnerability. The most effective approach involves implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in file inclusion operations. Developers should avoid directly using user input in include statements and instead implement a whitelist validation approach that only permits known good file paths. Additionally, disabling the ability to include remote files through PHP configuration settings such as setting allow_url_include to false in php.ini can prevent exploitation. The recommended remediation process includes upgrading to a patched version of the Knusperleicht Shoutbox software, as version 4.5 and later contain fixes for this vulnerability. Organizations should also implement network-level controls such as firewall rules that restrict access to vulnerable applications and monitor for suspicious patterns in web traffic that might indicate exploitation attempts. Security monitoring should focus on detecting attempts to include external URLs in file inclusion parameters, as this behavior would be highly indicative of exploitation activity. The vulnerability demonstrates the importance of secure coding practices and input validation, particularly for web applications that process user data in sensitive contexts.