CVE-2017-20208 in RegistrationMagic Plugin
Summary
by MITRE • 10/18/2025
The RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login plugin for WordPress is vulnerable to PHP Object Injection in all versions up to 3.7.9.3 (exclusive) via deserialization of untrusted input from the is_expired_by_date() function. This makes it possible for unauthenticated attackers to inject a PHP Object. The additional presence of a POP chain allows attackers to fetch a remote file and install it on the site.
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Analysis
by VulDB Data Team • 10/18/2025
The vulnerability identified as CVE-2017-20208 affects the RegistrationMagic plugin for WordPress, a widely used tool for creating custom registration forms, user management, and payment processing functionalities. This plugin has been installed on thousands of WordPress sites, making it a potentially significant attack vector for malicious actors targeting WordPress ecosystems. The vulnerability stems from improper input validation and sanitization within the plugin's codebase, specifically in how it handles user-supplied data during the deserialization process.
The technical flaw exists in the is_expired_by_date() function which processes untrusted input without adequate sanitization or validation. When PHP objects are serialized and then deserialized, they can execute arbitrary code if the serialized data contains malicious payloads. In this case, attackers can inject PHP objects through the plugin's input handling mechanism, bypassing authentication requirements entirely. This represents a classic PHP Object Injection vulnerability that falls under CWE-502, which specifically addresses the deserialization of untrusted data. The vulnerability allows attackers to execute arbitrary PHP code on the target system, effectively compromising the WordPress installation.
The operational impact of this vulnerability is severe as it enables unauthenticated remote code execution, meaning attackers can exploit the flaw without requiring valid credentials or prior access to the system. The presence of a POP (Property Object Pollution) chain within the vulnerability chain significantly amplifies the threat level by enabling attackers to chain multiple exploitation techniques together. This chaining capability allows for more sophisticated attack patterns where attackers can first inject malicious PHP objects, then leverage the POP chain to fetch remote files and install them on the compromised site. The attack can lead to complete system compromise, data exfiltration, and potential use as a foothold for further lateral movement within network environments.
Mitigation strategies should focus on immediate plugin updates to versions beyond 3.7.9.3 where the vulnerability has been patched. Administrators should also implement network-level protections such as web application firewalls that can detect and block suspicious deserialization patterns. Input validation and sanitization should be strengthened at all entry points, particularly where user data is processed. Security monitoring should include detection of unusual file operations and remote file inclusion attempts. Organizations should follow ATT&CK framework techniques such as T1059.007 for PHP code execution and T1071.004 for application layer protocol usage to detect and respond to exploitation attempts. Regular security audits and vulnerability assessments should be conducted to identify similar weaknesses in other plugins and themes, as this vulnerability demonstrates how seemingly minor input handling flaws can lead to complete system compromise.