CVE-2024-52439: Team Rosters Object Injection Vulnerability

CVE-2024-52439 Overview

CVE-2024-52439 is a critical Insecure Deserialization vulnerability affecting the Team Rosters plugin for WordPress, developed by Mark O'Donnell. The vulnerability allows Object Injection through deserialization of untrusted data, enabling remote attackers to potentially execute arbitrary code on affected systems. This issue affects all versions of Team Rosters through 4.6.

Critical Impact

This PHP Object Injection vulnerability can allow unauthenticated remote attackers to inject malicious serialized objects, potentially leading to complete site compromise, remote code execution, or unauthorized data access.

Affected Products

• WordPress Team Rosters Plugin versions through 4.6
• WordPress installations using vulnerable Team Rosters plugin versions
• Websites with exposed Team Rosters functionality accessible from the network

Discovery Timeline

• 2024-11-20 - CVE CVE-2024-52439 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-52439

Vulnerability Analysis

This vulnerability stems from improper handling of serialized PHP data within the Team Rosters WordPress plugin. When user-controlled input containing serialized data is passed to PHP's unserialize() function without adequate validation, attackers can craft malicious serialized objects that, when deserialized, trigger dangerous "magic methods" such as __wakeup() or __destruct(). This type of vulnerability, classified under CWE-502 (Deserialization of Untrusted Data), is particularly dangerous in PHP applications with complex class hierarchies.

The network-accessible attack vector with no authentication requirements makes this vulnerability highly exploitable. An attacker does not need any privileges or user interaction to exploit this flaw, meaning any publicly accessible WordPress site running the vulnerable plugin version is at risk.

Root Cause

The root cause is the deserialization of untrusted user input without proper sanitization or type enforcement. PHP's native unserialize() function, when used on untrusted data, can instantiate arbitrary objects and trigger their magic methods. If any class in the application's autoload path contains exploitable gadget chains, attackers can achieve code execution or other malicious outcomes. The Team Rosters plugin fails to validate or sanitize serialized input before processing, creating this critical attack surface.

Attack Vector

The attack exploits the network-accessible interface of the WordPress plugin where serialized data is processed. An attacker crafts a malicious serialized PHP object (often called a "POP chain" or "Property Oriented Programming" chain) containing carefully chosen class names and property values. When the vulnerable endpoint deserializes this payload, the PHP runtime instantiates the specified objects and executes their magic methods.

Depending on the classes available in the WordPress environment, exploitation can lead to arbitrary file operations, remote code execution via system commands, database manipulation, or complete site takeover. The attack typically proceeds as follows:

1. Attacker identifies the vulnerable deserialization endpoint in Team Rosters
2. Attacker generates a malicious serialized payload using known WordPress gadget chains
3. Payload is submitted to the vulnerable endpoint via network request
4. PHP deserializes the payload, instantiating attacker-controlled objects
5. Magic methods execute with attacker-controlled properties, achieving code execution

For detailed technical analysis of this vulnerability, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2024-52439

Indicators of Compromise

• Unusual HTTP requests to Team Rosters plugin endpoints containing serialized PHP data (look for strings starting with O:, a:, or s: patterns)
• Web server logs showing malformed or excessively long POST parameters to plugin-related URLs
• Unexpected PHP processes spawned by the web server user
• New or modified files in the WordPress installation directory, particularly in /wp-content/uploads/ or plugin directories
• Database modifications indicating unauthorized administrative access or new administrator accounts

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in request bodies
• Monitor access logs for requests to /wp-content/plugins/team-rosters/ endpoints with suspicious POST data
• Implement file integrity monitoring on WordPress core files and plugin directories
• Use security plugins that scan for known PHP Object Injection patterns in request parameters
• Enable and review PHP error logs for deserialization-related warnings or fatal errors

Monitoring Recommendations

• Configure SIEM alerts for patterns matching PHP serialization syntax in HTTP traffic
• Establish baseline network behavior and alert on anomalous traffic patterns to WordPress installations
• Monitor for process creation events from web server processes that may indicate post-exploitation activity
• Deploy endpoint detection to identify behavioral indicators of PHP-based exploitation
• Regularly audit installed WordPress plugins against vulnerability databases

How to Mitigate CVE-2024-52439

Immediate Actions Required

• Identify all WordPress installations using the Team Rosters plugin version 4.6 or earlier
• If a patched version is available, update the Team Rosters plugin immediately
• If no patch is available, consider temporarily deactivating the plugin until a fix is released
• Review web server logs for signs of exploitation attempts
• Implement WAF rules to block serialized PHP object patterns at the network perimeter

Patch Information

Consult the Patchstack Vulnerability Report for the latest patch status and remediation guidance. Check the WordPress plugin repository for updates to the Team Rosters plugin that address this vulnerability. Organizations should monitor for vendor security advisories and apply patches as soon as they become available.

Workarounds

• Temporarily disable or remove the Team Rosters plugin if it is not business-critical
• Implement a Web Application Firewall rule to block requests containing serialized PHP patterns (O:[0-9]+:, a:[0-9]+:, etc.)
• Restrict network access to WordPress administrative areas using IP allowlisting or VPN requirements
• Consider using WordPress security plugins that provide virtual patching capabilities for known vulnerabilities
• Conduct a security audit of all installed WordPress plugins and remove any that are unnecessary or unmaintained

# Example WAF rule pattern for ModSecurity to detect PHP serialized objects
SecRule REQUEST_BODY "@rx O:\d+:\"[^\"]+\":\d+:{" "id:100001,phase:2,deny,status:403,msg:'Potential PHP Object Injection detected'"