CVE-2008-6172 in RWCards
Summary
by MITRE
Directory traversal vulnerability in captcha/captcha_image.php in the RWCards (com_rwcards) 3.0.11 component for Joomla!, when magic_quotes_gpc is disabled, allows remote attackers to include and execute arbitrary local files via directory traversal sequences in the img parameter.
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Analysis
by VulDB Data Team • 11/08/2024
The vulnerability described in CVE-2008-6172 represents a critical directory traversal flaw within the RWCards component for Joomla! version 3.0.11. This issue specifically affects the captcha/captcha_image.php script where user input is not properly sanitized before being used in file inclusion operations. The vulnerability manifests when the PHP configuration parameter magic_quotes_gpc is disabled, which removes the automatic escaping of special characters in GET, POST, and COOKIE data. This configuration setting, when turned off, leaves applications more susceptible to injection attacks as input validation becomes the sole defense mechanism.
The technical exploitation of this vulnerability occurs through manipulation of the img parameter in the captcha_image.php script. Attackers can craft malicious directory traversal sequences such as ../../../../../etc/passwd or similar paths that traverse the filesystem upward from the intended directory. When magic_quotes_gpc is disabled, these traversal sequences are not escaped or filtered, allowing the application to interpret them as legitimate file paths. The vulnerability stems from improper input validation and sanitization, where the application directly uses user-supplied input to construct file paths without adequate security checks or canonicalization.
From an operational perspective, this vulnerability presents a severe risk to Joomla! installations using the affected RWCards component. Successful exploitation enables remote attackers to include and execute arbitrary local files on the web server, potentially leading to complete system compromise. Attackers can leverage this weakness to read sensitive system files, execute malicious code, or gain unauthorized access to the underlying server infrastructure. The impact extends beyond simple data theft as it can result in persistent backdoor access, privilege escalation, and full system control. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks. The attack vector aligns with techniques documented in the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1566 for credential access through exploitation of vulnerabilities.
The remediation strategy for this vulnerability requires immediate implementation of proper input validation and sanitization mechanisms. Organizations should ensure that all user-supplied input is thoroughly validated and filtered before being used in file operations. The most effective mitigation involves implementing strict path validation that prevents traversal sequences from being processed, typically by canonicalizing file paths or using allowlists of acceptable file paths. Additionally, administrators should enable magic_quotes_gpc or implement equivalent protection mechanisms at the application level. The Joomla! component should be updated to a patched version that properly handles file inclusion operations and validates all input parameters. Security monitoring should be enhanced to detect suspicious file access patterns and directory traversal attempts. System administrators must also consider implementing web application firewalls and input validation rules to prevent exploitation attempts. The vulnerability underscores the importance of secure coding practices and proper input validation as fundamental security controls that prevent many common attack vectors.