CVE-2008-5570 in PHP Multiple Newsletters
Summary
by MITRE
Directory traversal vulnerability in index.php in PHP Multiple Newsletters 2.7, when magic_quotes_gpc is disabled, allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the lang parameter.
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Analysis
by VulDB Data Team • 11/18/2024
The vulnerability described in CVE-2008-5570 represents a critical directory traversal flaw within the PHP Multiple Newsletters 2.7 application that specifically exploits the absence of proper input validation in the lang parameter of the index.php script. This weakness occurs when the PHP configuration has magic_quotes_gpc disabled, which removes the automatic escaping of special characters that would otherwise prevent malicious input from being interpreted as file system commands. The vulnerability enables remote attackers to manipulate the application's file inclusion mechanism by inserting directory traversal sequences such as .. into the lang parameter, thereby gaining unauthorized access to arbitrary local files on the server.
The technical exploitation of this vulnerability relies on the application's failure to sanitize user input before using it in file system operations. When magic_quotes_gpc is disabled, the application does not automatically escape forward slashes, backslashes, and other special characters that could be used to traverse directory structures. Attackers can construct malicious URLs that include sequences like ../../etc/passwd or similar paths to access sensitive files on the server. This flaw directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal vulnerabilities. The vulnerability exists because the application fails to implement proper input validation, sanitization, or access control mechanisms when processing the lang parameter.
The operational impact of this vulnerability is severe as it provides attackers with the ability to execute arbitrary code on the affected server. Once an attacker successfully exploits this vulnerability, they can read sensitive system files, potentially including configuration files, database credentials, or other critical data that could lead to complete system compromise. The vulnerability also allows for arbitrary file inclusion, which means attackers can potentially upload and execute malicious code, turning the affected server into a potential command and control node for further attacks. This type of vulnerability is particularly dangerous in web applications that run with elevated privileges, as it can provide attackers with access to system resources that should be restricted. The attack surface is further expanded when considering that this vulnerability can be exploited without authentication, making it a high-severity threat that can be leveraged by anyone with access to the vulnerable application.
Mitigation strategies for this vulnerability must address both the immediate technical flaw and implement broader security controls to prevent similar issues. The primary fix involves implementing proper input validation and sanitization for all user-supplied data, particularly parameters used in file system operations. The application should validate that the lang parameter contains only allowed characters and does not contain directory traversal sequences. Additionally, implementing a whitelist approach for language selection, where only pre-approved language files are allowed, would prevent arbitrary file inclusion. Organizations should also ensure that magic_quotes_gpc is properly configured or implement alternative input sanitization measures, as this vulnerability specifically requires the disabling of PHP's built-in protection mechanisms. From a defense-in-depth perspective, implementing proper access controls, restricting file system permissions, and employing web application firewalls can provide additional layers of protection. The vulnerability also highlights the importance of following secure coding practices as outlined in the OWASP Top Ten and the ATT&CK framework, particularly in the context of input validation and privilege management. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities in other applications and ensure that proper security controls are in place to prevent unauthorized file access and execution.