CVE-2015-9340 in wp-file-upload Plugin
Summary
by MITRE
The wp-file-upload plugin before 3.0.0 for WordPress has insufficient restrictions on upload of php, js, pht, php3, php4, php5, phtml, htm, html, and htaccess files.
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Analysis
by VulDB Data Team • 11/28/2023
The wp-file-upload plugin vulnerability represents a critical authorization flaw that undermines the security posture of WordPress installations. This issue affects versions prior to 3.0.0 and stems from inadequate validation mechanisms within the file upload functionality. The flaw allows attackers to bypass intended security restrictions and upload malicious files with extensions that typically should be prohibited. The vulnerability falls under the category of insecure file handling and represents a classic example of improper input validation that enables arbitrary file execution.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize and validate file extensions during the upload process. Attackers can exploit this weakness by uploading files with extensions such as php, js, pht, php3, php4, php5, phtml, htm, html, and htaccess that are commonly restricted to prevent code execution. The absence of comprehensive file type checking mechanisms means that even files with potentially dangerous extensions can be successfully uploaded to the target system. This vulnerability aligns with CWE-434 which describes the improper restriction of file uploads, and specifically relates to CWE-20 which covers insecure input validation.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads and creates significant risk for compromised WordPress installations. Successful exploitation allows attackers to execute arbitrary code on the target server, potentially leading to full system compromise, data theft, or establishment of persistent backdoors. The ability to upload php files specifically enables attackers to execute malicious code directly on the web server, while other file types like htaccess could potentially be used to modify server configuration and redirect traffic. This vulnerability maps directly to attack techniques described in the MITRE ATT&CK framework under T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter.
Organizations affected by this vulnerability should prioritize immediate remediation through plugin updates to version 3.0.0 or later, which implements proper file validation mechanisms. Additional mitigations include implementing strict file type whitelisting, configuring web server restrictions to prevent execution of uploaded files, and deploying web application firewalls with file upload filtering capabilities. Security best practices recommend implementing multiple layers of defense including proper file extension validation, content type checking, and server-side file verification. The vulnerability demonstrates the critical importance of proper input validation and access control mechanisms in web applications, particularly in content management systems that handle user-generated content. Organizations should also conduct regular security assessments to identify similar vulnerabilities in other plugins and components that may present similar authorization flaws.