CVE-2015-9341 in wp-file-upload Plugin
Summary
by MITRE
The wp-file-upload plugin before 3.4.1 for WordPress has insufficient restrictions on upload of .php.js files.
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Analysis
by VulDB Data Team • 11/28/2023
The wp-file-upload plugin vulnerability represents a critical security flaw in WordPress plugin ecosystems that has persisted for years. This issue affects versions prior to 3.4.1 and demonstrates how seemingly minor configuration oversights can create significant attack vectors. The vulnerability specifically targets the file upload validation mechanisms within the plugin, where certain file extensions are not properly restricted, allowing malicious actors to bypass security controls. The affected plugin operates within the broader WordPress framework, which serves as the foundation for millions of websites worldwide, making this vulnerability particularly dangerous as it could compromise entire web infrastructures.
The technical flaw manifests in the plugin's insufficient validation of file extensions, particularly allowing .php.js files to be uploaded without proper security checks. This occurs because the plugin fails to implement comprehensive file type verification that would normally reject potentially dangerous file extensions. The .php.js extension is particularly concerning as it combines characteristics of both php and js file types, potentially enabling attackers to execute malicious code through the WordPress environment. This vulnerability falls under the category of insecure file upload, which is classified as CWE-434 within the Common Weakness Enumeration framework. The flaw demonstrates poor input validation and inadequate sanitization of user-provided data, both of which are fundamental security principles that should be enforced at multiple layers within web applications.
The operational impact of this vulnerability extends far beyond the immediate plugin scope, as it provides attackers with a potential pathway to achieve remote code execution on vulnerable WordPress installations. When attackers successfully upload malicious .php.js files, they can leverage these files to execute arbitrary code on the web server, potentially leading to complete system compromise. The vulnerability aligns with ATT&CK technique T1190, which describes the use of compromised credentials or access to execute malicious code through web application vulnerabilities. This attack vector enables adversaries to establish persistent access, escalate privileges, and potentially move laterally within network environments. The impact is particularly severe because WordPress installations often contain sensitive data, user information, and business-critical content that could be compromised through this vulnerability.
Mitigation strategies for this vulnerability require immediate patching of the wp-file-upload plugin to version 3.4.1 or later, where proper file extension restrictions have been implemented. Organizations should also implement additional security measures including comprehensive file type validation at multiple levels, proper file extension whitelisting, and implementation of secure file storage practices. Network administrators should monitor for suspicious file uploads and implement web application firewalls to detect and block malicious upload attempts. The vulnerability highlights the importance of maintaining up-to-date security practices and demonstrates why automated security scanning should be integrated into all web application development and deployment workflows. Regular security audits and penetration testing can help identify similar vulnerabilities before they can be exploited by malicious actors.