CVE-2006-6568 in Kb Mods
Summary
by MITRE
Directory traversal vulnerability in includes/kb_constants.php in the Knowledge Base (mx_kb) 2.0.2 module for mxBB allows remote attackers to include arbitrary files via a .. (dot dot) sequence in the phpEx parameter.
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Analysis
by VulDB Data Team • 12/21/2024
The vulnerability identified as CVE-2006-6568 represents a critical directory traversal flaw within the mxBB Knowledge Base module version 2.0.2. This security weakness resides in the includes/kb_constants.php file and specifically affects the phpEx parameter handling mechanism. The vulnerability enables remote attackers to manipulate file inclusion paths through the exploitation of .. (dot dot) sequences, which allows them to traverse the directory structure and access files that should remain restricted. Such directory traversal vulnerabilities are particularly dangerous because they can potentially lead to unauthorized access to sensitive system files, configuration data, or even enable arbitrary code execution depending on the server configuration and the files accessible through the traversal path.
The technical implementation of this flaw stems from inadequate input validation and sanitization within the phpEx parameter processing logic. When the application receives a request containing a .. sequence in the phpEx parameter, it fails to properly validate or sanitize this input before using it in file inclusion operations. This lack of proper input filtering creates an opportunity for attackers to manipulate the file path resolution mechanism, effectively bypassing intended security boundaries. The vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This weakness allows attackers to access files and directories that are stored outside the intended directory structure, potentially leading to exposure of sensitive information or system compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially enable more severe consequences depending on the application's deployment environment and the permissions of the web server process. An attacker who successfully exploits this vulnerability could gain access to database configuration files containing credentials, application source code revealing implementation details, or system files that could provide insights into the underlying infrastructure. The attack vector is particularly concerning because it requires no authentication and can be executed remotely, making it accessible to any attacker with knowledge of the vulnerable application. This vulnerability aligns with ATT&CK technique T1083, which covers directory and file system discovery, and can potentially lead to T1566, the delivery of malicious code through web applications. The impact is amplified in environments where the web application has elevated privileges or where sensitive files are stored in accessible locations relative to the web root.
Mitigation strategies for CVE-2006-6568 should focus on implementing robust input validation and sanitization mechanisms throughout the application's file inclusion processes. The primary defense involves ensuring that all user-supplied input, particularly parameters used in file operations, undergoes strict validation to prevent the inclusion of directory traversal sequences. This can be achieved through the implementation of allow-list validation that only permits specific, expected values for the phpEx parameter, or by employing proper path normalization techniques that strip or reject traversal sequences before they are processed. Additionally, the application should be configured with minimal necessary permissions, ensuring that the web server process operates with the principle of least privilege. Organizations should also consider implementing web application firewalls that can detect and block suspicious traversal patterns in HTTP requests. The most effective long-term solution involves upgrading to a patched version of the mxBB Knowledge Base module or migrating to a more secure, supported knowledge management system. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities in other components of the application stack, as directory traversal flaws often occur in multiple locations within complex web applications.