CVE-2014-4912 in Frog
Summary
by MITRE
An Arbitrary File Upload issue was discovered in Frog CMS 0.9.5 due to lack of extension validation.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability identified as CVE-2014-4912 represents a critical arbitrary file upload flaw in Frog CMS version 0.9.5 that stems from insufficient input validation mechanisms. This issue allows authenticated attackers with CMS user privileges to upload malicious files to the web server, potentially leading to remote code execution and complete system compromise. The vulnerability specifically manifests due to the absence of proper file extension validation, enabling attackers to bypass security controls that should prevent the upload of potentially dangerous file types such as php, aspx, or other executable scripts.
From a technical perspective this vulnerability maps directly to CWE-434, which describes "Unrestricted Upload of File with Dangerous Type" and represents a classic insecure file upload vulnerability. The flaw exists in the CMS's file handling logic where the application fails to properly validate file extensions against a whitelist of allowed types, instead relying on client-side validation or no validation at all. This creates a dangerous attack surface where an authenticated user can upload files with extensions that could be executed by the web server, particularly when the server configuration allows execution of scripts in directories where uploaded files are stored.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to complete system compromise and persistent backdoor access. An attacker who gains access to a CMS user account can upload a web shell or malicious script that, when accessed through the web server, provides remote code execution capabilities. This allows for data exfiltration, system reconnaissance, lateral movement within the network, and establishment of persistent access points. The vulnerability is particularly concerning because it affects the content management system itself, which often has elevated privileges and direct access to application data and server resources.
The attack vector requires an authenticated user account within the CMS, but this presents a significant risk since CMS administrators often have elevated privileges and may be targeted through credential compromise or social engineering attacks. The vulnerability can be exploited through standard file upload interfaces within the CMS, making it accessible to attackers who can authenticate to the system. According to ATT&CK framework category T1505.003, this represents a "Web Shell" technique where attackers establish persistent access through uploaded malicious files. Organizations should implement proper input validation, maintain strict file type whitelists, and ensure uploaded files are stored in non-executable directories to prevent exploitation of this vulnerability.
Mitigation strategies should focus on implementing comprehensive file validation mechanisms that enforce strict whitelisting of allowed file extensions and MIME types. The CMS should be updated to a version that addresses this vulnerability, as Frog CMS 0.9.5 is no longer supported and lacks security patches. Additional protective measures include configuring web server settings to prevent execution of uploaded files in web-accessible directories, implementing proper access controls for file upload functionality, and conducting regular security audits of CMS installations. Security monitoring should also be enhanced to detect unauthorized file uploads and suspicious access patterns that may indicate exploitation attempts.