CVE-2025-31084: Sunshine Photo Cart Object Injection Flaw

CVE-2025-31084 Overview

CVE-2025-31084 is a critical Insecure Deserialization vulnerability affecting the Sunshine Photo Cart WordPress plugin. The vulnerability allows unauthenticated attackers to inject malicious serialized objects through the plugin's data processing mechanisms. When the application deserializes untrusted user input without proper validation, attackers can leverage existing "gadget chains" within WordPress or installed plugins to achieve arbitrary code execution, data manipulation, or complete site compromise.

Critical Impact

This PHP Object Injection vulnerability enables unauthenticated remote attackers to execute arbitrary code on vulnerable WordPress installations running Sunshine Photo Cart versions up to and including 3.4.10.

Affected Products

• Sunshine Photo Cart WordPress Plugin versions through 3.4.10
• WordPress installations with Sunshine Photo Cart plugin installed
• E-commerce sites using Sunshine Photo Cart for photo gallery sales

Discovery Timeline

• 2025-04-01 - CVE-2025-31084 published to NVD
• 2025-04-03 - Last updated in NVD database

Technical Details for CVE-2025-31084

Vulnerability Analysis

The Sunshine Photo Cart plugin contains an insecure deserialization flaw classified under CWE-502 (Deserialization of Untrusted Data). This vulnerability exists because the plugin processes serialized PHP data from user-controllable input without implementing adequate security controls.

PHP Object Injection occurs when an application uses unserialize() on data that an attacker can manipulate. The risk is significantly amplified in WordPress environments where numerous plugins may contain "magic methods" (such as __wakeup(), __destruct(), or __toString()) that execute automatically during the deserialization process.

The attack requires no authentication and can be initiated remotely over the network with low complexity. A successful exploit can result in complete compromise of confidentiality, integrity, and availability of the affected WordPress installation.

Root Cause

The root cause of CVE-2025-31084 is the improper handling of serialized data within the Sunshine Photo Cart plugin. The application fails to validate or sanitize serialized input before passing it to PHP's unserialize() function. Without proper safeguards such as allowlisting expected classes or using safer data interchange formats like JSON, attackers can craft malicious serialized payloads that instantiate arbitrary PHP objects with attacker-controlled properties.

Attack Vector

The attack is conducted over the network without requiring any privileges or user interaction. An attacker crafts a malicious serialized PHP object payload and submits it to a vulnerable endpoint within the Sunshine Photo Cart plugin. When the application deserializes this payload, it triggers the instantiation of PHP objects that can execute arbitrary code through available gadget chains.

The exploitation typically follows this pattern: the attacker identifies a vulnerable deserialization point, enumerates available classes with exploitable magic methods (either within WordPress core, the target plugin, or other installed plugins), constructs a Property-Oriented Programming (POP) chain, and delivers the serialized payload to achieve code execution.

For detailed technical analysis and proof-of-concept information, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-31084

Indicators of Compromise

• Unexpected PHP serialized strings containing unusual class names in web server access logs
• Presence of serialized payloads with O: prefixes in POST data or cookies targeting Sunshine Photo Cart endpoints
• New or modified files in the WordPress installation directory, particularly in wp-content/plugins/sunshine-photo-cart/
• Unauthorized administrative accounts or modified user privileges in the WordPress database

Detection Strategies

• Monitor web application firewall (WAF) logs for serialized PHP objects in request parameters, particularly targeting the Sunshine Photo Cart plugin paths
• Implement file integrity monitoring on WordPress core files, plugin directories, and theme files to detect unauthorized modifications
• Review web server access logs for suspicious POST requests to the plugin's AJAX handlers or REST API endpoints
• Deploy runtime application security monitoring to detect unserialize() calls on user-controllable input

Monitoring Recommendations

• Enable verbose logging for the Sunshine Photo Cart plugin and review logs for anomalous activity patterns
• Configure security information and event management (SIEM) rules to alert on serialized object patterns in HTTP traffic
• Implement database query monitoring to detect unauthorized changes to WordPress options or user metadata tables
• Utilize WordPress security plugins that provide real-time file change detection and malware scanning capabilities

How to Mitigate CVE-2025-31084

Immediate Actions Required

• Update Sunshine Photo Cart to a version newer than 3.4.10 immediately when a patch becomes available
• If no patch is available, temporarily deactivate and remove the Sunshine Photo Cart plugin from production WordPress installations
• Conduct a thorough security audit of affected WordPress sites to identify any indicators of prior exploitation
• Review and harden WordPress file permissions to minimize the impact of potential code execution

Patch Information

Site administrators should monitor the official WordPress plugin repository and the Sunshine Photo Cart vendor channels for security updates addressing this vulnerability. The Patchstack Vulnerability Report may contain updated remediation guidance as patches become available.

Workarounds

• Deploy a Web Application Firewall (WAF) with rules to block serialized PHP object payloads in incoming requests
• Restrict access to the WordPress admin area and plugin endpoints using IP allowlisting where feasible
• Implement network segmentation to limit the blast radius if a WordPress server is compromised
• Consider migrating to an alternative photo cart solution until an official patch is released

# WordPress hardening - restrict file permissions
find /var/www/html/wp-content/plugins/ -type f -exec chmod 644 {} \;
find /var/www/html/wp-content/plugins/ -type d -exec chmod 755 {} \;

# Block serialized PHP object injection at Apache level (example .htaccess rule)
# Add to WordPress root .htaccess
<IfModule mod_rewrite.c>
    RewriteCond %{QUERY_STRING} (O:|a:)[0-9]+: [NC,OR]
    RewriteCond %{REQUEST_BODY} (O:|a:)[0-9]+: [NC]
    RewriteRule .* - [F,L]
</IfModule>