CVE-2006-2693 in Hacks List
Summary
by MITRE
Directory traversal vulnerability in admin/admin_hacks_list.php in Nivisec Hacks List 1.20 and earlier for phpBB, when register_globals is enabled, allows remote attackers to read arbitrary files via a ".." in the phpEx parameter.
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Analysis
by VulDB Data Team • 09/11/2017
The vulnerability described in CVE-2006-2693 represents a critical directory traversal flaw within the Nivisec Hacks List plugin version 1.20 and earlier for phpBB platforms. This weakness specifically targets the admin/admin_hacks_list.php script where improper input validation allows malicious actors to manipulate file access patterns through the phpEx parameter. The vulnerability becomes exploitable when the phpBB forum system operates with register_globals enabled, a configuration that historically posed significant security risks due to its automatic creation of global variables from request data. The flaw enables remote attackers to traverse directory structures and access arbitrary files on the server, potentially exposing sensitive data including configuration files, user databases, and other system resources that should remain protected from unauthorized access.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input within the phpEx parameter handling mechanism. When register_globals is enabled, the phpBB application automatically creates global variables from HTTP request data, including GET and POST parameters. Attackers can exploit this by injecting directory traversal sequences using the ".." notation within the phpEx parameter, effectively bypassing normal file access controls. The vulnerability operates at the application layer and leverages the inherent insecurity of the register_globals directive, which was deprecated in php 5.3.0 and removed in php 5.4.0 due to its dangerous implications for web application security. This flaw directly corresponds to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The operational impact of this vulnerability extends beyond simple file disclosure, as it can lead to complete system compromise when combined with other attack vectors. An attacker who successfully exploits this vulnerability can potentially access phpBB configuration files containing database credentials, administrator passwords, and other sensitive information. The attack requires no authentication and can be executed remotely, making it particularly dangerous for publicly accessible phpBB installations. The vulnerability's exploitation demonstrates how legacy security configurations like register_globals can create persistent attack surfaces even in well-established web applications, highlighting the importance of proper input validation and secure coding practices. Organizations running affected versions of Nivisec Hacks List must consider this vulnerability as part of their broader security posture assessment, particularly in environments where outdated phpBB versions are still in use.
Mitigation strategies for CVE-2006-2693 involve multiple layers of defensive measures to protect against directory traversal attacks. The primary recommendation is to disable register_globals in php configuration settings, which effectively neutralizes the vulnerability by preventing automatic creation of global variables from request data. System administrators should upgrade to Nivisec Hacks List version 1.21 or later, which includes proper input validation and sanitization mechanisms to prevent directory traversal attempts. Additionally, implementing proper input validation on all user-supplied parameters including phpEx, using functions like realpath() to resolve absolute paths and comparing against allowed directories, provides additional protection layers. Network-level defenses such as web application firewalls can also detect and block malicious directory traversal attempts by monitoring for suspicious patterns in URL parameters. Organizations should also consider implementing principle of least privilege access controls, ensuring that web server processes run with minimal required permissions and that sensitive files are properly protected against unauthorized access. The vulnerability serves as a reminder of the importance of keeping web applications updated and avoiding deprecated security configurations that create unnecessary attack vectors.