CVE-2008-6253 in Pluck
Summary
by MITRE
Directory traversal vulnerability in data/inc/lib/pcltar.lib.php in Pluck 4.5.3, when register_globals is enabled, allows remote attackers to include and execute arbitrary local files via directory traversal sequences in the g_pcltar_lib_dir parameter.
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Analysis
by VulDB Data Team • 11/11/2024
The vulnerability described in CVE-2008-6253 represents a critical directory traversal flaw within the Pluck content management system version 4.5.3. This issue specifically affects systems where the PHP configuration parameter register_globals is enabled, creating an exploitable condition that enables remote attackers to manipulate file inclusion mechanisms. The vulnerability resides in the pcltar.lib.php library file located within the data/inc/lib directory structure of the Pluck installation, making it a core component of the application's file handling functionality.
The technical exploitation of this vulnerability occurs through manipulation of the g_pcltar_lib_dir parameter, which controls the directory path used for library file inclusion. When register_globals is enabled, attacker-controlled input can directly influence PHP variables within the global scope, allowing malicious users to inject directory traversal sequences such as ../../../etc/passwd or similar patterns. The flaw stems from inadequate input validation and sanitization of user-supplied parameters before they are used in file path construction and inclusion operations, creating a direct pathway for arbitrary local file inclusion attacks.
From an operational impact perspective, this vulnerability enables attackers to execute arbitrary code on the affected system by including and executing local files that should normally remain protected. The implications extend beyond simple file reading to full system compromise, as attackers can include system configuration files, web shell payloads, or other malicious components that may be present on the server. This type of vulnerability falls under the CWE-22 category for Improper Limitation of a Pathname to a Restricted Directory, and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: PowerShell, though the specific execution vector here involves PHP file inclusion rather than PowerShell directly. The vulnerability essentially provides an attacker with a backdoor into the system's file system through the legitimate file inclusion mechanism.
The mitigation strategies for this vulnerability require immediate action to address the root cause of the issue. The primary recommendation involves disabling the register_globals PHP configuration option, which removes the fundamental condition that allows the attack to succeed. Additionally, proper input validation and sanitization must be implemented to ensure that all user-supplied parameters are thoroughly checked before being used in file path operations. This includes implementing strict parameter validation, using allowlists for acceptable directory paths, and employing proper input filtering techniques. Organizations should also consider upgrading to newer versions of Pluck where this vulnerability has been addressed, and implementing web application firewalls to detect and block suspicious directory traversal patterns. The vulnerability demonstrates the critical importance of secure coding practices and the dangers of legacy PHP configurations that enable dangerous global variable exposure, making it a prime example of why proper security controls must be implemented at multiple layers of the application architecture.