CVE-2019-10869 in Ninja Forms Plugin
Summary
by MITRE
Path Traversal and Unrestricted File Upload exists in the Ninja Forms plugin before 3.0.23 for WordPress (when the Uploads add-on is activated). This allows an attacker to traverse the file system to access files and execute code via the includes/fields/upload.php (aka upload/submit page) name and tmp_name parameters.
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Analysis
by VulDB Data Team • 09/12/2023
The vulnerability identified as CVE-2019-10869 represents a critical security flaw in the Ninja Forms WordPress plugin affecting versions prior to 3.0.23. This vulnerability combines two serious security weaknesses that together create a dangerous attack vector for malicious actors targeting WordPress installations. The issue specifically manifests within the Uploads add-on functionality, which when activated provides users with the ability to upload files through the plugin's interface. The vulnerability exists in the includes/fields/upload.php file, which handles file upload operations and serves as the entry point for exploitation. This represents a classic path traversal vulnerability that allows attackers to manipulate file system access through improperly validated input parameters.
The technical flaw stems from inadequate validation of user-supplied input parameters, specifically the name and tmp_name parameters within the upload/submit page functionality. Attackers can exploit this weakness by crafting malicious file names that contain directory traversal sequences such as ../ or ..\ that allow them to navigate outside the intended upload directory. This vulnerability falls under CWE-22, which defines path traversal or directory traversal vulnerabilities where attackers can access files outside the intended directory by manipulating input parameters. The flaw enables attackers to upload malicious files to arbitrary locations on the server filesystem, potentially leading to remote code execution. When combined with unrestricted file upload capabilities, this creates a scenario where attackers can upload web shells, malicious scripts, or other harmful files that can be executed by the web server.
The operational impact of CVE-2019-10869 is severe and multifaceted, affecting WordPress administrators and end users who rely on the Ninja Forms plugin for form creation and file upload functionality. An attacker who successfully exploits this vulnerability can gain unauthorized access to sensitive system files, potentially compromising the entire WordPress installation and underlying server infrastructure. The vulnerability allows for complete system compromise through remote code execution, enabling attackers to establish persistent backdoors, exfiltrate data, or use the compromised server for further attacks. This represents a significant threat to organizations relying on WordPress platforms, as the vulnerability can be exploited without requiring authentication, making it particularly dangerous for publicly accessible websites. The attack surface is expanded due to the plugin's widespread use within the WordPress ecosystem, potentially affecting numerous websites and organizations.
Mitigation strategies for CVE-2019-10869 primarily focus on immediate patching and configuration hardening measures. The most effective solution involves upgrading the Ninja Forms plugin to version 3.0.23 or later, which includes proper input validation and sanitization for file upload parameters. Organizations should also implement restrictive file upload policies that validate file types, enforce strict naming conventions, and limit upload directories to prevent directory traversal attacks. Additional protective measures include implementing web application firewalls that can detect and block malicious upload attempts, configuring proper file permissions to restrict write access to upload directories, and conducting regular security audits of WordPress installations. From an ATT&CK framework perspective, this vulnerability maps to techniques involving file execution and privilege escalation, requiring organizations to implement comprehensive security controls that address both the immediate vulnerability and broader attack surface management. Network segmentation and monitoring solutions should be deployed to detect suspicious upload activities and potential exploitation attempts.