CVE-2024-50507: DS.DownloadList Object Injection Flaw

CVE-2024-50507 Overview

A Deserialization of Untrusted Data vulnerability exists in the Daschmi DS.DownloadList WordPress plugin. This vulnerability allows attackers to perform PHP Object Injection attacks, which can lead to arbitrary code execution, data manipulation, or complete site compromise depending on available gadget chains within the WordPress installation.

Critical Impact

This PHP Object Injection vulnerability enables attackers to inject malicious serialized objects that, when deserialized, can execute arbitrary code or perform unauthorized actions on vulnerable WordPress sites running DS.DownloadList plugin version 1.3 or earlier.

Affected Products

• Daschmi DS.DownloadList WordPress Plugin versions through 1.3
• WordPress installations using the dsdownloadlist plugin

Discovery Timeline

• 2024-10-30 - CVE-2024-50507 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2024-50507

Vulnerability Analysis

This vulnerability is classified as CWE-502 (Deserialization of Untrusted Data). The DS.DownloadList plugin fails to properly validate or sanitize serialized data before passing it to PHP's unserialize() function. When user-controlled data is deserialized without proper validation, attackers can craft malicious serialized objects that trigger dangerous operations when instantiated.

PHP Object Injection vulnerabilities are particularly dangerous in WordPress environments due to the extensive plugin ecosystem. An attacker can leverage existing class definitions (known as "gadget chains") within WordPress core, themes, or other installed plugins to achieve various malicious outcomes including remote code execution, file manipulation, or database modification.

Root Cause

The root cause of this vulnerability lies in the unsafe handling of serialized data within the DS.DownloadList plugin. The plugin accepts externally-supplied serialized data and deserializes it without implementing proper validation mechanisms such as:

• Input sanitization before deserialization
• Allowlist of permitted classes for deserialization
• Use of safe serialization alternatives like JSON

This architectural flaw allows attackers to manipulate the serialized payload to instantiate arbitrary objects with attacker-controlled properties.

Attack Vector

The attack vector involves submitting crafted serialized PHP objects to the vulnerable plugin endpoint. The exploitation process typically follows these steps:

1. Reconnaissance: The attacker identifies the WordPress site is running the vulnerable DS.DownloadList plugin
2. Gadget Chain Discovery: The attacker analyzes the WordPress installation for exploitable class definitions
3. Payload Construction: A malicious serialized object is crafted that triggers dangerous magic methods (__wakeup(), __destruct(), etc.) upon deserialization
4. Exploitation: The payload is submitted to the vulnerable endpoint, causing the malicious object to be instantiated

The vulnerability requires no authentication and can be exploited remotely through network requests to the affected WordPress site. For technical details and specific exploitation methods, refer to the Patchstack security advisory.

Detection Methods for CVE-2024-50507

Indicators of Compromise

• Unusual serialized data patterns in HTTP requests containing PHP object notation (e.g., O:8:"ClassName":1:{s:4:"prop";s:5:"value";})
• Web server logs showing requests with serialized PHP payloads targeting plugin endpoints
• Unexpected file modifications or new files created in WordPress directories
• Suspicious database entries containing serialized object data
• Error logs showing PHP deserialization warnings or unexpected class instantiation errors

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect serialized PHP object patterns in HTTP requests
• Monitor for requests containing typical serialized object signatures targeting /wp-content/plugins/dsdownloadlist/ paths
• Deploy file integrity monitoring to detect unauthorized changes to WordPress core files, themes, and plugins
• Enable verbose logging on WordPress installations and analyze for deserialization-related errors

Monitoring Recommendations

• Configure real-time alerting for HTTP requests containing serialized PHP object patterns
• Establish baseline behavior for the DS.DownloadList plugin and alert on deviations
• Implement centralized log collection from WordPress servers for correlation analysis
• Monitor outbound network connections from WordPress servers that could indicate post-exploitation activity

How to Mitigate CVE-2024-50507

Immediate Actions Required

• Deactivate and remove the DS.DownloadList plugin immediately if version 1.3 or earlier is installed
• Audit WordPress installations for any signs of compromise before and after remediation
• Review web server logs for suspicious requests that may indicate exploitation attempts
• Consider implementing a Web Application Firewall (WAF) with PHP deserialization attack detection capabilities

Patch Information

As of the published vulnerability data, DS.DownloadList versions through 1.3 are affected. Site administrators should check for updated versions of the plugin that address this vulnerability. If no patched version is available, removing the plugin entirely is recommended. Monitor the Patchstack advisory for updates on patch availability.

Workarounds

• Remove the DS.DownloadList plugin entirely until a secure version is released
• Deploy WAF rules to block requests containing serialized PHP object patterns
• Implement input validation at the web server level using ModSecurity or similar tools
• Restrict access to WordPress admin and plugin directories using IP-based access controls
• Consider using a WordPress security plugin that provides real-time attack detection and blocking

# WordPress plugin removal example
# Navigate to WordPress plugins directory
cd /var/www/html/wp-content/plugins/

# Remove vulnerable plugin
rm -rf dsdownloadlist/

# Verify removal
ls -la | grep dsdownloadlist

# Clear WordPress cache if applicable
wp cache flush --allow-root