CVE-2016-1209 in Ninja Forms Plugin
Summary
by MITRE
The Ninja Forms plugin before 2.9.42.1 for WordPress allows remote attackers to conduct PHP object injection attacks via crafted serialized values in a POST request.
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Analysis
by VulDB Data Team • 01/23/2025
The vulnerability identified as CVE-2016-1209 affects the Ninja Forms plugin for WordPress, specifically versions prior to 2.9.42.1, presenting a critical security risk that enables remote attackers to execute PHP object injection attacks. This flaw resides in the plugin's handling of user-supplied data within POST requests, where crafted serialized PHP objects can be manipulated to achieve unauthorized code execution. The vulnerability demonstrates a classic object injection flaw that exploits the lack of proper input validation and sanitization mechanisms within the plugin's data processing pipeline. The attack vector operates through the manipulation of serialized data structures that are typically used to transmit complex data between client and server, making this a sophisticated threat that requires careful analysis of the plugin's internal architecture and data flow mechanisms.
The technical implementation of this vulnerability stems from the plugin's insecure deserialization practices, where user-provided serialized PHP objects are directly processed without adequate validation or sanitization. When a malicious actor crafts a POST request containing specially crafted serialized data, the plugin's code attempts to unserialize this data without proper security checks, allowing the attacker to inject malicious PHP objects that can execute arbitrary code on the target system. This vulnerability aligns with CWE-502, which specifically addresses the deserialization of untrusted data, and represents a fundamental flaw in the plugin's security architecture that permits attackers to bypass normal access controls and execute malicious payloads. The attack scenario involves the manipulation of form data submission processes where the serialized objects contain malicious code that gets executed when the plugin processes the data, creating a persistent threat vector that can be exploited across multiple installations.
The operational impact of this vulnerability extends beyond simple code execution to encompass full system compromise and potential data breaches. Attackers can leverage this vulnerability to gain unauthorized access to WordPress installations, potentially leading to complete server compromise, data exfiltration, and the deployment of additional malicious tools or backdoors. The vulnerability affects not only individual plugin functionality but also the broader WordPress ecosystem, as compromised installations can serve as launch points for attacks on other systems within the network. This represents a significant risk to website administrators and organizations relying on WordPress platforms, particularly those running outdated versions of the Ninja Forms plugin where the patch has not been applied. The vulnerability's exploitation can result in unauthorized modification of website content, user data theft, and establishment of persistent access points that are difficult to detect and remove from the compromised systems.
Mitigation strategies for CVE-2016-1209 require immediate patch application to upgrade the Ninja Forms plugin to version 2.9.42.1 or later, which contains the necessary security fixes to prevent object injection attacks. Organizations should also implement comprehensive monitoring and intrusion detection systems to identify potential exploitation attempts and establish network segmentation to limit the impact of successful compromises. Security hardening measures should include disabling unnecessary PHP functions, implementing proper input validation at all levels, and conducting regular security audits of WordPress installations. The vulnerability demonstrates the critical importance of keeping all plugins and themes updated, as well as implementing defense-in-depth strategies that include web application firewalls and proper access controls. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command and control communications and privilege escalation, making it a significant concern for organizations implementing comprehensive threat hunting and incident response capabilities. Regular security assessments and vulnerability scanning should be conducted to identify similar insecure deserialization practices within other plugins and themes that may present similar attack surfaces.