CVE-2024-8420: DHVC Form Privilege Escalation Vulnerability

CVE-2024-8420 Overview

The DHVC Form plugin for WordPress contains a critical privilege escalation vulnerability affecting all versions up to and including 2.4.7. The vulnerability stems from improper access control in the user registration functionality, where the plugin fails to properly validate or restrict the role field during user registration. This design flaw allows unauthenticated attackers to register new administrator accounts on vulnerable WordPress installations, effectively granting complete control over the affected website.

Critical Impact

Unauthenticated attackers can register as administrators on vulnerable WordPress sites, leading to complete site compromise including data theft, malware injection, and website defacement.

Affected Products

• DHVC Form plugin for WordPress versions up to and including 2.4.7
• Sitesao DHVC Form (WordPress Visual Composer integration)
• WordPress installations running vulnerable DHVC Form versions

Discovery Timeline

• 2025-02-28 - CVE-2024-8420 published to NVD
• 2025-03-06 - Last updated in NVD database

Technical Details for CVE-2024-8420

Vulnerability Analysis

This privilege escalation vulnerability falls under CWE-266 (Incorrect Privilege Assignment) and CWE-269 (Improper Privilege Management). The DHVC Form plugin implements user registration functionality that accepts user-supplied input for the WordPress user role without proper authorization checks or input validation.

In WordPress, user roles define the capabilities and permissions available to each user account. The administrator role has full control over the WordPress installation, including the ability to modify files, install plugins, edit content, and access sensitive data. By allowing unauthenticated users to specify their own role during registration, the plugin completely bypasses WordPress's built-in privilege management system.

The vulnerability is particularly dangerous because it requires no authentication, no user interaction, and can be exploited remotely over the network. An attacker simply needs to craft a registration request that includes the role parameter set to administrator to gain full administrative access to the target WordPress site.

Root Cause

The root cause of this vulnerability is the absence of proper access control and input validation on the user role parameter during the registration process. The DHVC Form plugin accepts and processes the role field from user-submitted registration forms without verifying that the requester has appropriate permissions to assign administrative privileges. Secure implementations should either restrict role assignment to authenticated administrators only or remove the role parameter from public-facing registration forms entirely.

Attack Vector

The attack vector is network-based and requires no privileges or user interaction. An attacker can exploit this vulnerability by:

1. Identifying a WordPress site running a vulnerable version of the DHVC Form plugin
2. Locating the registration form endpoint provided by the plugin
3. Submitting a crafted registration request that includes the role parameter set to administrator
4. Gaining immediate administrator access to the WordPress dashboard

The exploitation is straightforward and does not require specialized tools or technical expertise. Once administrator access is obtained, the attacker can install backdoors, inject malicious code, exfiltrate sensitive data, or use the compromised site for further attacks.

Detection Methods for CVE-2024-8420

Indicators of Compromise

• Newly created WordPress administrator accounts with unfamiliar usernames or email addresses
• User registration logs showing role assignment to administrator for newly created accounts
• Unexpected changes to WordPress core files, themes, or plugins
• New or modified files in the wp-content/uploads or plugin directories
• Unusual outbound network connections from the WordPress server

Detection Strategies

• Monitor WordPress user registration events for accounts created with elevated privileges
• Implement file integrity monitoring on WordPress installations to detect unauthorized modifications
• Review web server access logs for POST requests to DHVC Form registration endpoints containing role parameters
• Configure alerts for new administrator account creation in WordPress

Monitoring Recommendations

• Enable WordPress audit logging plugins to track user creation and privilege changes
• Set up automated alerts for any new administrator accounts registered on the site
• Regularly review the WordPress users table for unauthorized administrative accounts
• Monitor web application firewall (WAF) logs for suspicious registration form submissions

How to Mitigate CVE-2024-8420

Immediate Actions Required

• Audit existing WordPress administrator accounts and remove any unauthorized users
• Disable the DHVC Form plugin until a patched version is available
• Review WordPress activity logs for signs of exploitation
• If compromise is suspected, reset all administrator passwords and regenerate WordPress salts

Patch Information

As of the last update to the NVD database on 2025-03-06, site administrators should check the Codecanyon WordPress Plugin page for updated versions. Additionally, review the Wordfence Vulnerability Report for the latest security advisories and patch information from the vendor.

Workarounds

• Deactivate and delete the DHVC Form plugin if it is not essential to site operations
• Implement a Web Application Firewall (WAF) rule to block registration requests containing the role parameter
• Restrict access to registration endpoints using .htaccess or server-level access controls
• Consider using alternative WordPress form plugins that follow secure coding practices

# Apache .htaccess rule to block suspicious role parameter in POST requests
# Add to WordPress root .htaccess file
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD} POST
RewriteCond %{QUERY_STRING} role=administrator [NC,OR]
RewriteCond %{REQUEST_BODY} role=administrator [NC]
RewriteRule .* - [F,L]
</IfModule>