CVE-2018-17573 in Wp-Insert Plugin
Summary
by MITRE
The Wp-Insert plugin through 2.4.2 for WordPress allows upload of arbitrary PHP code because of the exposure and configuration of FCKeditor under fckeditor/editor/filemanager/browser/default/browser.html, fckeditor/editor/filemanager/connectors/test.html, and fckeditor/editor/filemanager/connectors/uploadtest.html.
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Analysis
by VulDB Data Team • 05/19/2023
The vulnerability identified as CVE-2018-17573 affects the Wp-Insert plugin version 2.4.2 and earlier installations within WordPress environments. This security flaw stems from improper configuration of the FCKeditor component, which is embedded within the plugin to provide rich text editing capabilities. The vulnerability manifests through the exposure of FCKeditor's file management interfaces, specifically targeting three critical endpoints: fckeditor/editor/filemanager/browser/default/browser.html, fckeditor/editor/filemanager/connectors/test.html, and fckeditor/editor/filemanager/connectors/uploadtest.html. These paths represent the core components of the file manager system that should normally be restricted and properly authenticated.
The technical implementation flaw allows unauthenticated attackers to exploit the exposed file upload functionality within the FCKeditor framework. This vulnerability directly maps to CWE-434, which describes "Unrestricted Upload of File with Dangerous Type," as it permits the upload of arbitrary PHP code without proper validation or authentication mechanisms. The FCKeditor's default configuration fails to implement adequate access controls, allowing any user to navigate to these endpoints and potentially upload malicious files. The exposed test and upload interfaces provide attackers with direct pathways to execute code on the affected WordPress server, as these components are designed to facilitate file management operations but lack proper authorization checks.
The operational impact of this vulnerability is severe and multifaceted within WordPress environments. Attackers can leverage this weakness to upload malicious PHP files that can execute arbitrary code on the target server, potentially leading to complete system compromise. This vulnerability enables threat actors to establish persistent backdoors, exfiltrate sensitive data, or deploy additional malware. The attack surface extends beyond simple code execution to include potential privilege escalation opportunities, as the uploaded files can be executed with the privileges of the web server process. The vulnerability affects all WordPress installations using the vulnerable Wp-Insert plugin version, making it particularly dangerous in environments where multiple users have access to the WordPress admin interface.
Mitigation strategies for CVE-2018-17573 should focus on immediate remediation and long-term security hardening. The primary solution involves upgrading to a patched version of the Wp-Insert plugin, as the vulnerability was addressed in subsequent releases. Organizations should also implement proper access controls by restricting access to the exposed FCKeditor endpoints through web server configuration or firewall rules. Network segmentation and web application firewalls can provide additional layers of protection by monitoring and blocking suspicious file upload attempts. Security professionals should conduct thorough audits of all installed plugins to identify similar vulnerabilities in other components. The ATT&CK framework categorizes this vulnerability under T1190 "Exploit Public-Facing Application" and T1059.007 "Command and Scripting Interpreter: PowerShell," as the compromised system can be used for further lateral movement and command execution. Regular security scanning and monitoring of file upload functionalities should be implemented to detect similar misconfigurations across the entire WordPress ecosystem.