CVE-2025-31002: Squeeze File Upload Vulnerability

CVE-2025-31002 Overview

CVE-2025-31002 is an Unrestricted Upload of File with Dangerous Type vulnerability (CWE-434) affecting the Squeeze WordPress plugin developed by Bogdan Bendziukov. This vulnerability allows attackers to upload malicious files to vulnerable WordPress installations, potentially leading to complete site compromise through remote code execution.

The vulnerability exists due to insufficient file type validation in the plugin's upload functionality, enabling attackers to bypass security controls and upload files containing executable code such as PHP web shells.

Critical Impact

Attackers can upload malicious files including PHP web shells, potentially achieving full remote code execution on the WordPress server and complete site takeover.

Affected Products

• WordPress Squeeze Plugin version 1.6 and earlier
• All WordPress installations running vulnerable versions of the Squeeze plugin

Discovery Timeline

• April 9, 2025 - CVE-2025-31002 published to NVD
• April 1, 2026 - Last updated in NVD database

Technical Details for CVE-2025-31002

Vulnerability Analysis

This vulnerability stems from improper validation of uploaded file types in the Squeeze WordPress plugin. When processing file uploads, the plugin fails to adequately verify that uploaded files are of safe, expected types. This oversight allows attackers to upload files with dangerous extensions (such as .php, .phtml, or other executable formats) that can be executed on the server.

Once a malicious file is uploaded and placed in a web-accessible directory, an attacker can access the file directly through the web server, triggering execution of the malicious code. This typically results in full remote code execution with the privileges of the web server process.

Root Cause

The root cause of CVE-2025-31002 is the absence of proper file type validation during the upload process. The plugin likely relies solely on client-side validation or fails to implement server-side checks for:

• File extension verification against an allowlist
• MIME type validation
• File content inspection to detect embedded code
• Proper sanitization of uploaded filenames

Without these controls, the upload mechanism accepts any file type, including those that pose security risks when executed on the server.

Attack Vector

An attacker can exploit this vulnerability by crafting a malicious file disguised or presented as a legitimate upload. The attack typically follows this sequence:

1. The attacker identifies a WordPress site running the vulnerable Squeeze plugin (version 1.6 or earlier)
2. Using the plugin's upload functionality, the attacker submits a malicious PHP file (such as a web shell)
3. The file bypasses inadequate validation and is stored on the server in a web-accessible location
4. The attacker accesses the uploaded file via a direct URL request
5. The web server executes the PHP code, granting the attacker remote code execution capabilities

This attack can be performed remotely without authentication if the upload functionality is publicly accessible, making it particularly dangerous for internet-facing WordPress installations.

Detection Methods for CVE-2025-31002

Indicators of Compromise

• Unexpected PHP files appearing in WordPress upload directories (wp-content/uploads/)
• Files with suspicious names or double extensions (e.g., image.php.jpg, shell.php)
• Web shell signatures in uploaded files containing functions like eval(), exec(), system(), or passthru()
• Unusual outbound connections from the web server to unknown IP addresses
• Unexpected administrative actions or user account creations in WordPress logs

Detection Strategies

• Implement file integrity monitoring (FIM) on WordPress directories to detect unauthorized file additions
• Monitor web server access logs for requests to unusual file paths within upload directories
• Deploy web application firewall (WAF) rules to detect and block web shell upload attempts
• Scan upload directories regularly for files containing PHP code or executable content
• Use SentinelOne's behavioral AI to detect post-exploitation activities associated with web shell usage

Monitoring Recommendations

• Enable verbose logging for the Squeeze plugin and WordPress core file operations
• Configure alerts for new file creations in wp-content/uploads/ with executable extensions
• Monitor for suspicious process spawning from the web server process (e.g., www-data spawning shell commands)
• Implement network monitoring for command-and-control traffic patterns from the web server

How to Mitigate CVE-2025-31002

Immediate Actions Required

• Disable or uninstall the Squeeze plugin immediately if a patched version is not available
• Audit upload directories for any suspicious or unexpected files and remove malicious content
• Review WordPress access logs for signs of exploitation attempts
• Implement temporary WAF rules to block file upload requests to the Squeeze plugin endpoints
• Consider placing the WordPress site behind additional security controls until remediation is complete

Patch Information

At the time of this analysis, the vulnerability affects Squeeze plugin version 1.6 and all prior versions. Site administrators should check the Patchstack WordPress Vulnerability Database for the latest patch availability and update information.

If no patch is available, consider removing the plugin entirely and finding an alternative solution that provides equivalent functionality with proper security controls.

Workarounds

• Configure the web server to prevent PHP execution in upload directories by adding .htaccess rules (Apache) or equivalent nginx configuration
• Implement server-side file type validation using additional security plugins like Wordfence or Sucuri
• Restrict upload directory permissions to prevent write access where possible
• Use a web application firewall to filter malicious upload attempts based on file content inspection

# Apache .htaccess configuration to prevent PHP execution in uploads directory
# Add this to wp-content/uploads/.htaccess

<FilesMatch "\.(?:php|phtml|php3|php4|php5|php7|phps)$">
    Order Allow,Deny
    Deny from all
</FilesMatch>

# Alternative: Disable all script execution
<IfModule mod_php7.c>
    php_flag engine off
</IfModule>