CVE-2006-0785 in PHPKIT
Summary
by MITRE
Absolute path traversal vulnerability in include.php in PHPKIT 1.6.1 Release 2 and earlier allows remote attackers to include and execute arbitrary local files via a direct request with a path parameter with a null character and beginning with (1) / (slash) for an absolute pathname or (2) a drive letter (such as "C:"), which bypasses checks for ".." sequences and trailing ".php" extensions.
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Analysis
by VulDB Data Team • 07/08/2021
The CVE-2006-0785 vulnerability represents a critical absolute path traversal flaw in PHPKIT 1.6.1 Release 2 and earlier versions that fundamentally undermines the application's security model. This vulnerability resides within the include.php component and exploits a design flaw that fails to properly validate user-supplied path parameters. The vulnerability operates by allowing remote attackers to manipulate the path parameter through direct HTTP requests, creating a pathway for arbitrary local file inclusion and execution. The flaw specifically targets the application's input validation mechanisms that are meant to prevent directory traversal attacks by checking for ".." sequences and ensuring proper file extensions. However, the vulnerability's exploitation technique leverages a sophisticated bypass mechanism that incorporates null character injection alongside absolute path specifications beginning with forward slashes or drive letters, effectively circumventing these security controls. This allows attackers to construct malicious requests that can access any file on the server's filesystem, potentially leading to complete system compromise.
The technical implementation of this vulnerability stems from improper input sanitization and validation within the PHPKIT application's file inclusion logic. When the application processes a path parameter that begins with a forward slash or drive letter, combined with a null character, the validation checks that normally prevent directory traversal are bypassed entirely. The null character injection technique effectively terminates string processing at the null byte, allowing the attacker to inject arbitrary absolute paths that would otherwise be rejected by conventional validation rules. This bypass mechanism is particularly dangerous because it operates at the core level of file system access, enabling attackers to include any local file on the server that the application process has permission to access. The vulnerability's design flaw specifically relates to CWE-22, which describes improper limitation of a pathname to a restricted directory, and represents a classic example of how inadequate input validation can lead to arbitrary code execution. The attack vector demonstrates sophisticated understanding of how null character handling can be exploited to circumvent security controls, making it particularly challenging to detect and prevent through traditional security measures.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it provides attackers with complete control over the affected system. Successful exploitation can lead to arbitrary code execution, data theft, system compromise, and potential lateral movement within network environments. Attackers can leverage this vulnerability to execute malicious payloads, access sensitive configuration files, read database credentials, or even establish backdoors for persistent access. The vulnerability's ability to bypass common security controls makes it particularly attractive to threat actors who seek to gain unauthorized access to web applications. The risk is amplified by the fact that this vulnerability affects a widely used content management system, making it a prime target for automated attacks and exploit frameworks. Organizations running affected versions of PHPKIT face significant exposure to compromise, as the vulnerability can be exploited without requiring authentication or specialized knowledge beyond basic web application exploitation techniques. This makes it particularly dangerous in environments where multiple applications are deployed and where the vulnerability could be used as a stepping stone for broader network infiltration.
Mitigation strategies for CVE-2006-0785 must address both the immediate vulnerability and implement broader security controls to prevent similar issues. The most effective immediate solution involves upgrading to PHPKIT version 1.6.2 or later, where the vulnerability has been patched through improved input validation and path sanitization. Organizations should implement strict input validation that rejects all absolute paths and null character sequences in file inclusion parameters. Network-based mitigations include implementing web application firewalls that can detect and block suspicious path traversal patterns, particularly those involving null characters and absolute path specifications. The implementation of principle of least privilege should be enforced, ensuring that web application processes have minimal required file system permissions. Security monitoring should include detection of unusual file access patterns and attempts to include files with absolute paths. Additionally, organizations should conduct comprehensive security assessments of their web applications to identify similar vulnerabilities that may exist in other components or third-party libraries. This vulnerability highlights the importance of following secure coding practices as outlined in the OWASP Top Ten and emphasizes the need for robust input validation mechanisms that consider all possible bypass techniques. Regular security updates and patch management processes should be implemented to prevent exploitation of known vulnerabilities, while also maintaining awareness of emerging threats that could leverage similar attack patterns. The vulnerability serves as a reminder that even seemingly simple input validation checks can be bypassed through sophisticated techniques, requiring security professionals to think beyond conventional attack vectors when designing defensive measures.