CVE-2008-4490 in phpAbook
Summary
by MITRE
Directory traversal vulnerability in config.inc.php in phpAbook 0.8.8b and earlier, when magic_quotes_gpc is disabled, allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the userInfo cookie.
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Analysis
by VulDB Data Team • 11/06/2024
The vulnerability identified as CVE-2008-4490 represents a critical directory traversal flaw in the phpAbook web application version 0.8.8b and earlier. This vulnerability specifically targets the config.inc.php file which serves as the application's configuration endpoint. The flaw manifests when the PHP magic_quotes_gpc directive is disabled, creating an exploitable condition where remote attackers can manipulate cookie values to achieve unauthorized file inclusion and execution. The vulnerability operates through a simple yet effective technique involving the use of .. (dot dot) sequences within the userInfo cookie parameter to navigate the file system hierarchy.
The technical implementation of this vulnerability stems from improper input validation and sanitization within the phpAbook application's cookie handling mechanism. When magic_quotes_gpc is disabled, the application fails to adequately filter or sanitize user-supplied input from the userInfo cookie, allowing attackers to inject directory traversal sequences. The .. (dot dot) notation enables attackers to move up directory levels and access files outside the intended application scope. This weakness 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 exploits the fundamental principle that web applications should never trust user input and must always validate and sanitize all external data before processing.
The operational impact of this vulnerability is severe and multifaceted, potentially enabling complete system compromise. Remote attackers can leverage this flaw to include and execute arbitrary local files on the web server, which could range from system configuration files to sensitive database credentials. The attack vector allows for privilege escalation and persistent access to the compromised system, making it particularly dangerous for web applications hosting sensitive data. This vulnerability directly aligns with ATT&CK technique T1059, which encompasses the use of command and scripting interpreters, as attackers can execute arbitrary code through the file inclusion mechanism. The potential for data exfiltration, system reconnaissance, and further lateral movement within the network makes this vulnerability a prime target for exploitation by malicious actors.
Mitigation strategies for CVE-2008-4490 must address both the immediate vulnerability and implement broader security controls. The primary remediation involves upgrading to a patched version of phpAbook beyond 0.8.8b where the directory traversal issue has been resolved. Additionally, administrators should ensure that magic_quotes_gpc is properly configured, though it's important to note that this directive has been deprecated in modern PHP versions. Implementing proper input validation and sanitization mechanisms is crucial, including the use of allowlist-based validation for cookie parameters and strict path validation before file operations. Security measures should also include disabling unnecessary file inclusion features and implementing proper access controls. Organizations should conduct regular security assessments and maintain up-to-date vulnerability management processes to identify and remediate similar issues across their web application portfolio. The vulnerability serves as a reminder of the critical importance of secure coding practices and proper input validation in preventing directory traversal attacks.