CVE-2025-31087: WooCommerce Plugin Object Injection Flaw

CVE-2025-31087 Overview

CVE-2025-31087 is a critical deserialization of untrusted data vulnerability affecting the Multiple Shipping And Billing Address For Woocommerce WordPress plugin developed by silverplugins217. This vulnerability enables PHP Object Injection attacks, allowing unauthenticated attackers to inject arbitrary objects into the application through maliciously crafted serialized data.

PHP Object Injection vulnerabilities occur when user-controllable input is passed to PHP's unserialize() function without proper validation. When combined with suitable "gadget chains" present in the application or its dependencies, attackers can achieve remote code execution, file manipulation, or other severe impacts.

Critical Impact

Unauthenticated attackers can exploit this vulnerability to inject malicious PHP objects, potentially leading to remote code execution, data exfiltration, or complete site compromise on affected WooCommerce installations.

Affected Products

• Multiple Shipping And Billing Address For Woocommerce plugin versions from n/a through 1.5
• WordPress installations running the vulnerable plugin versions
• WooCommerce stores utilizing the affected address management functionality

Discovery Timeline

• April 1, 2025 - CVE-2025-31087 published to NVD
• April 1, 2025 - Last updated in NVD database

Technical Details for CVE-2025-31087

Vulnerability Analysis

This vulnerability is classified as CWE-502 (Deserialization of Untrusted Data). The Multiple Shipping And Billing Address For Woocommerce plugin fails to properly sanitize or validate serialized data before passing it to PHP's unserialize() function.

The attack can be executed remotely over the network without requiring authentication or user interaction. An attacker who successfully exploits this vulnerability could achieve complete compromise of confidentiality, integrity, and availability of the affected system.

PHP Object Injection attacks work by exploiting the behavior of magic methods like __wakeup(), __destruct(), or __toString() that are automatically invoked during the deserialization process. If the application or any loaded library contains classes with exploitable magic methods (known as "gadget chains"), attackers can chain these together to achieve arbitrary code execution.

Root Cause

The root cause of this vulnerability lies in the insecure handling of serialized data within the plugin's address management functionality. The plugin processes user-supplied serialized input without implementing proper validation, type checking, or allowlisting of permitted object classes.

When storing or retrieving multiple shipping and billing addresses, the plugin likely uses PHP serialization for data persistence. Without proper safeguards such as:

• Using json_encode()/json_decode() instead of serialization
• Implementing allowed_classes option in unserialize()
• Validating input before deserialization

The plugin becomes vulnerable to object injection attacks.

Attack Vector

The attack vector for CVE-2025-31087 is network-based, requiring no authentication or user interaction. An attacker can craft a malicious serialized PHP object payload and submit it through the plugin's address input mechanisms.

The exploitation process typically involves:

1. Identifying the vulnerable input parameter that processes serialized data
2. Analyzing the WordPress installation and plugins for exploitable gadget chains
3. Crafting a malicious serialized payload that leverages available gadgets
4. Submitting the payload through the vulnerable endpoint
5. The malicious object is instantiated and its magic methods execute the attacker's code

Common exploitation targets include WordPress core classes, WooCommerce components, or other installed plugins that contain exploitable magic method implementations. For detailed technical information, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-31087

Indicators of Compromise

• Unusual serialized data patterns in HTTP request parameters, particularly containing PHP class names like O: followed by object definitions
• Unexpected file modifications in WordPress directories, especially wp-content/uploads/ or plugin directories
• New or modified PHP files with suspicious names or obfuscated code
• Anomalous database entries containing serialized objects with unexpected class references
• Web server logs showing requests with base64-encoded or URL-encoded serialized PHP objects

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in HTTP requests
• Monitor WordPress file integrity for unauthorized modifications using security plugins or external monitoring tools
• Implement logging for all requests to WooCommerce-related endpoints, especially those handling address data
• Use SentinelOne's Singularity platform to detect post-exploitation activities such as suspicious process execution or file system modifications
• Scan for known PHP Object Injection payloads targeting common WordPress gadget chains

Monitoring Recommendations

• Enable verbose logging on WordPress installations and regularly review for suspicious activity patterns
• Configure alerts for new user account creation or privilege escalation events
• Monitor outbound network connections from the web server for potential data exfiltration or reverse shell connections
• Track plugin file changes using version control or file integrity monitoring solutions
• Implement real-time monitoring of PHP process execution for anomalous behavior

How to Mitigate CVE-2025-31087

Immediate Actions Required

• Immediately update the Multiple Shipping And Billing Address For Woocommerce plugin to a patched version beyond 1.5 if available
• If no patch is available, consider temporarily deactivating the plugin until a fix is released
• Review WordPress installations for signs of compromise and perform security audits
• Implement WAF rules to block PHP serialization patterns in user input
• Ensure WordPress core, WooCommerce, and all plugins are updated to their latest versions

Patch Information

Organizations should check the plugin's official repository or the WordPress plugin directory for security updates addressing CVE-2025-31087. For the most current patch status and remediation guidance, consult the Patchstack Vulnerability Report.

Contact silverplugins217 directly if updated versions are not yet available through normal distribution channels. Monitor security advisories for updates regarding this vulnerability.

Workarounds

• Temporarily disable the Multiple Shipping And Billing Address For Woocommerce plugin if business operations permit
• Implement input validation at the web server level to reject requests containing serialized PHP objects
• Use a Web Application Firewall with rules specifically designed to detect PHP Object Injection attempts
• Consider alternative WooCommerce plugins for multiple address management until a patch is released
• Restrict administrative access to the WordPress installation using IP allowlisting or VPN requirements

# Configuration example
# Add to .htaccess to block common PHP serialization patterns
# Note: This is a defense-in-depth measure, not a complete fix

<IfModule mod_rewrite.c>
    RewriteEngine On
    # Block requests containing serialized PHP objects
    RewriteCond %{QUERY_STRING} (O:[0-9]+:") [NC,OR]
    RewriteCond %{REQUEST_BODY} (O:[0-9]+:") [NC]
    RewriteRule .* - [F,L]
</IfModule>

# Alternatively, configure ModSecurity rule
# SecRule REQUEST_BODY "@rx O:\d+:\"" "id:1001,phase:2,deny,status:403,msg:'PHP Object Injection Attempt'"