CVE-2024-37934: Ninja Forms Code Injection Vulnerability

CVE-2024-37934 Overview

CVE-2024-37934 is a critical Code Injection vulnerability affecting the Ninja Forms plugin for WordPress. The vulnerability allows improper control of code generation, enabling attackers to execute arbitrary shortcodes on vulnerable WordPress installations. This flaw exists in Ninja Forms versions up through 3.8.4 and poses a significant risk to WordPress sites utilizing this popular form building plugin.

Critical Impact

Unauthenticated remote attackers can exploit this Code Injection vulnerability to execute arbitrary shortcodes, potentially leading to complete site compromise, data theft, or further malicious code execution on affected WordPress installations.

Affected Products

• Ninja Forms plugin for WordPress versions through 3.8.4
• WordPress installations running vulnerable Ninja Forms versions
• Sites with subscriber-level user access enabled

Discovery Timeline

• 2024-07-09 - CVE-2024-37934 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-37934

Vulnerability Analysis

This vulnerability is classified as CWE-94 (Improper Control of Generation of Code) and enables arbitrary shortcode execution on affected WordPress installations. The flaw allows attackers with subscriber-level access to execute arbitrary WordPress shortcodes through the Ninja Forms plugin. Since shortcodes can trigger various WordPress functions and plugin behaviors, successful exploitation could lead to complete site compromise.

The vulnerability requires network access and can be exploited without user interaction, making it particularly dangerous for publicly accessible WordPress sites. The impact spans confidentiality, integrity, and availability of the affected systems.

Root Cause

The root cause of CVE-2024-37934 lies in improper input validation and sanitization within the Ninja Forms plugin's shortcode handling mechanism. The plugin fails to adequately restrict which shortcodes can be executed, allowing users with subscriber-level privileges to invoke arbitrary shortcodes that should be restricted to administrators.

Attack Vector

The attack can be executed remotely over the network without requiring any user interaction. An attacker with at minimum subscriber-level access to the WordPress site can craft malicious requests that trigger arbitrary shortcode execution through the Ninja Forms plugin. This could be leveraged to:

• Execute shortcodes from other plugins that perform privileged actions
• Potentially escalate privileges within the WordPress installation
• Access sensitive configuration data
• Manipulate site content and functionality

The vulnerability manifests in the shortcode execution handling within Ninja Forms. For detailed technical analysis, refer to the Patchstack Ninja Forms Vulnerability Analysis.

Detection Methods for CVE-2024-37934

Indicators of Compromise

• Unusual shortcode execution patterns in WordPress logs
• Unexpected activity from subscriber-level user accounts
• Anomalous form submissions or API requests to Ninja Forms endpoints
• Evidence of shortcode injection attempts in access logs

Detection Strategies

• Monitor WordPress access logs for suspicious requests targeting Ninja Forms endpoints
• Implement Web Application Firewall (WAF) rules to detect shortcode injection patterns
• Audit subscriber and user activity for unusual shortcode-related operations
• Review Ninja Forms configurations for unexpected changes

Monitoring Recommendations

• Enable detailed logging for the Ninja Forms plugin
• Configure alerts for subscriber accounts performing administrative-type actions
• Monitor for new or modified shortcodes being registered unexpectedly
• Implement file integrity monitoring on WordPress core and plugin files

How to Mitigate CVE-2024-37934

Immediate Actions Required

• Update Ninja Forms plugin to the latest patched version immediately
• Review subscriber-level user accounts for any suspicious activity
• Audit WordPress logs for evidence of exploitation attempts
• Consider temporarily disabling the Ninja Forms plugin until patched

Patch Information

Organizations should update Ninja Forms to a version newer than 3.8.4 that addresses this vulnerability. Check the official Ninja Forms changelog and the Patchstack vulnerability database for the specific patched version information.

Workarounds

• Restrict subscriber registration if not required for business operations
• Implement additional access controls at the server or WAF level
• Consider using a security plugin that restricts shortcode execution capabilities
• Apply the principle of least privilege to all WordPress user accounts

# WordPress CLI command to check Ninja Forms version
wp plugin list --name=ninja-forms --fields=name,version,status

# Update Ninja Forms to latest version
wp plugin update ninja-forms

# Verify the update was successful
wp plugin list --name=ninja-forms --fields=name,version,update_version