CVE-2019-19983 in Fast Velocity Minify
Summary
by MITRE
In the WordPress plugin, Fast Velocity Minify before 2.7.7, the full web root path to the running WordPress application can be discovered. In order to exploit this vulnerability, FVM Debug Mode needs to be enabled and an admin-ajax request needs to call the fastvelocity_min_files action.
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Analysis
by VulDB Data Team • 03/17/2024
The vulnerability identified as CVE-2019-19983 affects the Fast Velocity Minify WordPress plugin version 2.7.7 and earlier, presenting a critical information disclosure risk that exposes the complete web root path of the WordPress installation. This flaw represents a significant security concern as it provides attackers with sensitive directory structure information that can be leveraged for further exploitation attempts. The vulnerability specifically manifests when the plugin's debug mode is enabled, creating an attack vector that requires minimal privileges to exploit. The disclosure occurs through an admin-ajax request that invokes the fastvelocity_min_files action, making it accessible to authenticated users with appropriate permissions. This type of information disclosure vulnerability falls under the CWE-200 category, which encompasses information exposure issues that can provide attackers with valuable system information. The attack requires an attacker to have access to the WordPress admin area or be able to make authenticated requests to the admin-ajax.php endpoint, which represents a significant operational risk given the prevalence of WordPress installations and their administrative interfaces.
The technical implementation of this vulnerability stems from improper handling of debug information within the plugin's file processing mechanism. When FVM Debug Mode is enabled, the plugin's internal operations expose directory paths in its response handling for the fastvelocity_min_files action. This occurs because the debug functionality does not properly sanitize or restrict the information returned during file processing operations. The vulnerability is particularly concerning because it operates at the filesystem level, providing attackers with direct access to the absolute path structure of the web server. This information can be used to craft more sophisticated attacks such as path traversal exploits or to identify potential file inclusion vulnerabilities within the WordPress installation. The attack vector specifically requires an authenticated session or the ability to make requests to the admin-ajax.php endpoint, which means that even if the plugin is publicly accessible, the vulnerability is not automatically exploitable without proper credentials or session access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it significantly reduces the security posture of WordPress installations using the affected plugin. Attackers who can access the web root path information can better plan subsequent attacks by understanding the directory structure and potentially identifying other sensitive files or directories that might be accessible through path traversal techniques. This vulnerability is particularly dangerous in environments where WordPress is installed in non-standard directories or where the web root path contains sensitive information about the server configuration. The disclosure of absolute paths can also aid in fingerprinting attacks, helping attackers identify the exact version of WordPress and potentially other installed plugins or themes. Additionally, this information can be used to bypass certain security controls that rely on path-based access restrictions or to craft more targeted attacks against the WordPress installation. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous in large-scale attacks or reconnaissance phases.
Mitigation strategies for CVE-2019-19983 focus primarily on updating to the patched version of the Fast Velocity Minify plugin, specifically version 2.7.7 or later, which addresses the information disclosure issue. Organizations should immediately disable debug mode in the plugin configuration when it is not actively needed for troubleshooting purposes, as this significantly reduces the attack surface. The recommended approach involves implementing proper access controls to prevent unauthorized access to the admin-ajax.php endpoint and ensuring that only legitimate administrative users have access to the plugin's debug functionality. Security measures should include monitoring for unusual requests to the admin-ajax.php endpoint and implementing rate limiting or other controls to prevent automated exploitation attempts. The vulnerability also highlights the importance of proper input validation and output sanitization in web applications, as the issue stems from inadequate protection of sensitive information during debug operations. Organizations should consider implementing web application firewalls or other security controls that can detect and block malicious requests targeting the specific action hook mentioned in the vulnerability. This vulnerability demonstrates the critical importance of secure coding practices and proper configuration management in WordPress plugins, particularly those that handle file operations or debugging functionality. The ATT&CK framework categorizes this vulnerability under information gathering techniques, where adversaries collect system information to plan further attacks, making it a valuable reconnaissance tool for threat actors.