CVE-2016-10958 in estatik Plugin
Summary
by MITRE
The estatik plugin before 2.3.0 for WordPress has unauthenticated arbitrary file upload via es_media_images[] to wp-admin/admin-ajax.php.
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Analysis
by VulDB Data Team • 12/25/2023
The estatik plugin for WordPress contains a critical security vulnerability that allows unauthenticated attackers to upload arbitrary files to a targeted system. This flaw exists in versions prior to 2.3.0 and specifically affects the plugin's handling of media image uploads through the wp-admin/admin-ajax.php endpoint. The vulnerability stems from insufficient input validation and access control mechanisms within the plugin's file upload functionality, creating an avenue for remote code execution and potential system compromise.
The technical flaw manifests through the es_media_images[] parameter which is processed without proper authentication checks or file type validation. When an attacker submits a malicious file through this parameter to the admin-ajax.php endpoint, the plugin fails to verify the requester's authorization status or validate the uploaded file's content. This absence of security controls allows any remote user to bypass authentication requirements and upload potentially harmful files such as web shells, malware, or other malicious executables directly to the WordPress installation directory.
The operational impact of this vulnerability is severe and multifaceted. An unauthenticated attacker can gain persistent access to the compromised WordPress site, potentially leading to complete system takeover. The uploaded files can be executed directly by the web server, enabling attackers to establish backdoors, exfiltrate data, or use the compromised system as a launchpad for further attacks within the network. Additionally, the vulnerability can be exploited to deploy malicious scripts that may deface the website, inject malicious content, or perform other harmful activities. The lack of authentication requirements means that this attack can be executed without any prior credentials, making it particularly dangerous for WordPress installations that do not properly secure their admin endpoints.
This vulnerability maps directly to CWE-434 Unrestricted Upload of File with Dangerous Type, which is a well-documented weakness in software security that occurs when applications allow users to upload files without proper validation of file types or content. The issue also aligns with ATT&CK technique T1190 Exploit Public-Facing Application, as it represents an attack vector through a publicly accessible WordPress plugin endpoint. Organizations using the estatik plugin version 2.2.9 or earlier should immediately implement mitigations including plugin updates, access control restrictions, and monitoring of file upload activities. The recommended solution involves upgrading to version 2.3.0 or later where the vulnerability has been patched, implementing proper input validation, and restricting access to wp-admin/admin-ajax.php endpoints through firewall rules or web application firewalls to prevent exploitation attempts.