CVE-2008-5418 in PunPortal module
Summary
by MITRE
Directory traversal vulnerability in login.php in the PunPortal module before 2.0 for PunBB allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the pun_user[language] parameter.
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Analysis
by VulDB Data Team • 11/11/2024
The CVE-2008-5418 vulnerability represents a critical directory traversal flaw within the PunPortal module for PunBB platforms, specifically affecting versions prior to 2.0. This vulnerability exists in the login.php script and demonstrates a classic path traversal attack vector that enables remote attackers to access arbitrary local files on the server. The flaw occurs when the application fails to properly validate user input provided through the pun_user[language] parameter, allowing malicious actors to manipulate file paths using directory traversal sequences such as .. to navigate outside of intended directories. The vulnerability is particularly dangerous because it enables attackers to include and execute local files, potentially leading to complete system compromise. This issue 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. The vulnerability operates within the context of web application security where input validation failures create opportunities for attackers to bypass access controls and gain unauthorized access to system resources. The attack vector is particularly concerning because it requires no authentication to exploit, making it accessible to anyone who can interact with the vulnerable application.
The technical implementation of this vulnerability stems from the application's insecure handling of user-supplied language parameters during the login process. When the pun_user[language] parameter contains directory traversal sequences, the application processes these inputs without adequate sanitization or validation, allowing the attacker to specify arbitrary file paths. This flaw enables attackers to include local files that should normally be restricted, potentially leading to the execution of malicious code or exposure of sensitive system information. The vulnerability's impact extends beyond simple file access, as it can facilitate further exploitation through code injection techniques. According to ATT&CK framework, this vulnerability aligns with T1059.007 for command and scripting interpreter, specifically shell script, and T1566.001 for spearphishing attachment, as attackers can leverage this weakness to deploy malicious payloads. The flaw demonstrates poor input validation practices and inadequate access control mechanisms, creating an environment where attackers can manipulate application behavior through crafted input parameters.
The operational impact of CVE-2008-5418 is severe and multifaceted, potentially allowing attackers to execute arbitrary code on the affected server, access sensitive configuration files, read database credentials, or even obtain shell access to the underlying operating system. This vulnerability can lead to complete system compromise, data exfiltration, and persistent backdoor installation. Organizations running vulnerable PunBB installations are exposed to significant risk, particularly in environments where the application serves as a gateway to internal systems. The vulnerability can be exploited to access not only language files but potentially other sensitive system resources, including configuration files, database connection details, and application source code. The attack surface is broad due to the nature of directory traversal, as it can be combined with other techniques to escalate privileges and maintain persistent access. Security professionals should consider this vulnerability when assessing web application security posture, as it represents a fundamental flaw in input validation that can be exploited across multiple attack scenarios.
Mitigation strategies for CVE-2008-5418 focus on implementing proper input validation and sanitization mechanisms within the application. The most effective approach involves removing or escaping special characters from user input, particularly directory traversal sequences such as .. and /, before processing them in file operations. Organizations should implement strict parameter validation that ensures all language parameters conform to expected patterns and do not contain path traversal sequences. The recommended solution includes updating to PunPortal version 2.0 or later, which contains fixes for this vulnerability. Additionally, implementing proper access controls and restricting file inclusion to predefined, safe directories can prevent unauthorized file access. Security measures should include input filtering at multiple levels, including web application firewalls, server-side validation, and proper file access controls. Organizations should also consider implementing the principle of least privilege, ensuring that web applications run with minimal required permissions and that file system access is restricted to necessary components only. Regular security audits and vulnerability assessments are essential to identify and remediate similar issues before they can be exploited by malicious actors.