CVE-2014-9574 in FluxBB
Summary
by MITRE
Directory traversal vulnerability in install.php in FluxBB before 1.5.8 allows remote attackers to include and execute arbitrary local install.php files via a .. (dot dot) in the install_lang parameter.
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Analysis
by VulDB Data Team • 04/08/2018
The vulnerability identified as CVE-2014-9574 represents a critical directory traversal flaw within the FluxBB bulletin board system prior to version 1.5.8. This security weakness exists in the install.php script which is typically used during the initial setup and installation process of the forum software. The flaw manifests when the application fails to properly validate user-supplied input parameters, specifically the install_lang parameter that controls which language file to load during installation. Attackers can exploit this vulnerability by manipulating the install_lang parameter to include directory traversal sequences using the .. (dot dot) notation, allowing them to access and execute arbitrary local files on the server hosting the vulnerable FluxBB installation.
The technical nature of this vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This type of vulnerability occurs when applications fail to sanitize input that contains directory path information, enabling attackers to navigate outside the intended directory structure and access files that should remain restricted. In the context of FluxBB's install.php script, the vulnerability specifically targets the language file inclusion mechanism where the application directly incorporates user-provided language identifiers without adequate validation or sanitization. The flaw essentially allows an attacker to bypass normal file access controls and potentially execute malicious code by referencing files outside the intended installation directory.
The operational impact of CVE-2014-9574 extends beyond simple unauthorized file access, as it provides attackers with the capability to execute arbitrary code on the target system. During the installation phase, when the install.php script is typically accessible and active, attackers can leverage this vulnerability to gain remote code execution privileges. This represents a severe security risk because it allows adversaries to potentially compromise the entire server hosting the vulnerable FluxBB installation, especially if the installation script runs with elevated privileges. The attack vector is particularly dangerous because it targets the installation process, which often occurs in environments where security controls may be less stringent than in production systems. Additionally, since the vulnerability affects the installation script itself, it can be exploited even before the forum is fully configured, potentially allowing attackers to establish persistent access or deploy malicious payloads during the initial setup.
Mitigation strategies for this vulnerability require immediate patching of affected FluxBB installations to version 1.5.8 or later, which contains the necessary input validation fixes. Organizations should also implement proper input sanitization measures that validate and filter all user-supplied parameters, particularly those used for file inclusion operations. The remediation process should include reviewing and restricting access to installation scripts, ensuring they are only accessible during legitimate installation periods and properly secured afterward. Security best practices dictate that installation and setup scripts should not be publicly accessible and should be removed or secured once the initial configuration is complete. Additionally, implementing web application firewalls and input validation controls can provide additional layers of defense against similar directory traversal attacks. The vulnerability serves as a reminder of the importance of proper input validation and the principle of least privilege when implementing web applications, particularly during installation and configuration phases where elevated privileges may be temporarily required.