CVE-2025-3623: Uncanny Automator RCE Vulnerability

CVE-2025-3623 Overview

The Uncanny Automator plugin for WordPress contains a critical PHP Object Injection vulnerability affecting all versions up to and including 6.4.0.1. This insecure deserialization flaw exists in the automator_api_decode_message() function, which processes untrusted input without proper validation. Due to the presence of a Property-Oriented Programming (POP) chain within the application, unauthenticated attackers can exploit this vulnerability to delete arbitrary files on the affected system.

Critical Impact

Unauthenticated attackers can inject malicious PHP objects leading to arbitrary file deletion, potentially resulting in complete site takeover or denial of service.

Affected Products

• Uncanny Automator WordPress Plugin versions ≤ 6.4.0.1
• WordPress installations with vulnerable Uncanny Automator plugin
• All WordPress configurations using affected plugin versions

Discovery Timeline

• 2025-05-14 - CVE-2025-3623 published to NVD
• 2025-08-12 - Last updated in NVD database

Technical Details for CVE-2025-3623

Vulnerability Analysis

This PHP Object Injection vulnerability (CWE-502: Deserialization of Untrusted Data) represents a severe security flaw in the Uncanny Automator plugin's API message handling functionality. The vulnerability allows unauthenticated attackers to inject specially crafted serialized PHP objects through the automator_api_decode_message() function without authentication requirements.

What makes this vulnerability particularly dangerous is the combination of insecure deserialization with an available POP (Property-Oriented Programming) chain. When a malicious serialized object is deserialized, the POP chain enables attackers to chain together existing code gadgets within the application to achieve arbitrary file deletion. This attack surface requires no user interaction and can be exploited remotely over the network, making it highly accessible to threat actors.

The impact extends beyond simple file deletion—attackers could potentially delete critical WordPress files such as wp-config.php, effectively taking the site offline or forcing a reinstallation scenario. Additionally, selective file deletion could be used to disable security plugins or remove access controls.

Root Cause

The root cause lies in the automator_api_decode_message() function located in class-automator-recipe-helpers.php. This function deserializes user-supplied input without implementing proper validation or sanitization mechanisms. The function directly processes incoming API messages that can contain serialized PHP objects, trusting this input implicitly. Combined with magic methods (__destruct, __wakeup, etc.) present in the codebase that form a POP chain, this creates an exploitable pathway for attackers to execute dangerous operations during the deserialization process.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can craft a malicious HTTP request containing a specially serialized PHP object targeting the vulnerable API endpoint. When the automator_api_decode_message() function processes this request, it deserializes the malicious payload. The deserialization triggers the POP chain, which ultimately executes the file deletion operation. The attacker can specify arbitrary file paths within the serialized object, enabling deletion of critical system or WordPress files.

The vulnerability in the automator_api_decode_message() function processes serialized data without proper type checking or allowlist validation. When exploited, attackers leverage existing class destructors and magic methods to form a POP chain that results in arbitrary file operations. For detailed technical analysis, refer to the WordPress Code Helper reference and the Wordfence Vulnerability Report.

Detection Methods for CVE-2025-3623

Indicators of Compromise

• Unexpected HTTP requests to Uncanny Automator API endpoints containing serialized PHP data patterns (e.g., O: prefix indicating object serialization)
• Missing or unexpectedly deleted WordPress core files, configuration files, or plugin files
• Web server logs showing requests with unusually long or encoded payloads targeting /wp-json/ or plugin-specific endpoints
• File system audit logs indicating deletion events without corresponding administrative actions

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block requests containing serialized PHP object patterns (O:[0-9]+:, a:[0-9]+:, s:[0-9]+:)
• Monitor access logs for unusual API request patterns targeting Uncanny Automator endpoints
• Deploy file integrity monitoring (FIM) solutions to detect unauthorized file deletions or modifications
• Configure intrusion detection systems to alert on deserialization attack signatures

Monitoring Recommendations

• Enable comprehensive logging for all WordPress API endpoints and review logs regularly for anomalous patterns
• Implement real-time file integrity monitoring on critical WordPress directories including wp-includes/, wp-admin/, and wp-content/
• Set up alerts for any unexpected changes to wp-config.php or other critical configuration files
• Monitor plugin update status and ensure alerting when security patches become available

How to Mitigate CVE-2025-3623

Immediate Actions Required

• Update Uncanny Automator plugin to version 6.4.0.2 or later immediately
• Audit file system for any signs of unauthorized file deletions if exploitation is suspected
• Review web server access logs for indicators of attempted exploitation
• Consider temporarily disabling the Uncanny Automator plugin if immediate patching is not possible

Patch Information

Uncanny Owl has released a security patch in version 6.4.0.2 that addresses this vulnerability. The fix modifies the automator_api_decode_message() function to properly validate and sanitize input before deserialization. The patch details can be reviewed at the WordPress Change Set 3276577. Full changelog information is available at the Automator Plugin Changelog.

Workarounds

• Deploy a Web Application Firewall (WAF) with rules blocking serialized PHP object patterns in request bodies
• Implement network-level filtering to restrict access to WordPress API endpoints from untrusted sources
• Use WordPress security plugins that can detect and block deserialization attack attempts
• Consider disabling the Uncanny Automator plugin entirely until patching can be completed

# WordPress CLI plugin update command
wp plugin update uncanny-automator --version=6.4.0.2

# Verify current installed version
wp plugin list --name=uncanny-automator --fields=name,version,status

# Check file integrity of WordPress core files
wp core verify-checksums