CVE-2008-1512 in Module Xs
Summary
by MITRE
Directory traversal vulnerability in admin/admin_xs.php in eXtreme Styles module (XS-Mod) 2.3.1 and 2.4.0 for phpBB allows remote attackers to include and execute arbitrary files via a .. (dot dot) in the phpEx parameter. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 10/20/2024
The vulnerability identified as CVE-2008-1512 represents a critical directory traversal flaw within the eXtreme Styles module version 2.3.1 and 2.4.0 for phpBB platforms. This security weakness exists in the admin/admin_xs.php script which fails to properly validate user input parameters, specifically the phpEx parameter that controls file inclusion operations. The flaw enables remote attackers to manipulate the application's file handling mechanisms by exploiting the .. (dot dot) sequence in the parameter, allowing them to traverse the directory structure and access files outside the intended scope. This directory traversal vulnerability falls under the CWE-22 category, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious request containing the .. sequence within the phpEx parameter, which bypasses the intended security controls designed to restrict file access within the application's administrative interface. The eXtreme Styles module, which provides advanced styling capabilities for phpBB forums, incorrectly processes the user-supplied parameter without adequate sanitization or validation, creating an opportunity for arbitrary file inclusion attacks. This flaw directly enables attackers to include and execute arbitrary files on the target server, potentially leading to complete system compromise. The vulnerability demonstrates a classic lack of input validation and output encoding practices that are fundamental to preventing such attacks.
The operational impact of this vulnerability extends beyond simple data exposure, as it provides attackers with the capability to execute arbitrary code on the affected server. Successful exploitation could result in unauthorized access to sensitive system files, database credentials, or administrative interfaces, potentially leading to full system compromise. Attackers could leverage this vulnerability to upload malicious files, establish persistent backdoors, or conduct further reconnaissance activities within the compromised network. The attack surface is particularly concerning given that phpBB is a widely deployed forum platform, making this vulnerability a significant risk to numerous websites and organizations that rely on the platform for community engagement and communication.
Organizations affected by this vulnerability should implement immediate mitigations including updating to patched versions of the eXtreme Styles module, implementing proper input validation for all user-supplied parameters, and applying web application firewalls to detect and block malicious traversal attempts. The vulnerability highlights the importance of secure coding practices such as implementing proper parameter validation, using allowlists for file operations, and following the principle of least privilege when configuring file access permissions. Additionally, system administrators should conduct thorough security assessments of all installed phpBB extensions and modules to identify similar vulnerabilities that may exist in other components of the platform. This incident underscores the critical need for regular security updates and the implementation of defense-in-depth strategies to protect web applications from path traversal and arbitrary file inclusion attacks.