CVE-2023-4627

Executive Summary

CVE-2023-4627 is a Missing Authorization vulnerability in the LadiApp plugin for WordPress, affecting versions up to and including 4.4. The vulnerability resides in the save_config() function, which lacks a capability check, allowing authenticated attackers with subscriber-level access or above to modify the ladipage_config option. This can lead to unauthorized configuration changes, potentially enabling further attacks such as stored XSS or privilege escalation. The CVSS score is 4.3 (Medium), and the EPSS score is 0.0%, indicating low exploitation likelihood. No official patch has been released.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor for updates and consider disabling the plugin if no patch is available. The plugin is not available on NPM, PyPI, Go, or Ruby ecosystems.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Subscriber-level)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: Low
• Availability Impact: None

The threat level is considered Medium due to the low privileges required and the potential for configuration manipulation, which could lead to further compromise.

Deep Dive & Mechanics

The vulnerability exists in the save_config() function of the LadiApp plugin. This function is intended to save configuration settings for the plugin. However, it fails to perform a capability check (e.g., current_user_can('manage_options')) before processing the request. As a result, any authenticated user, including those with subscriber-level access, can send a POST request to the vulnerable endpoint and modify the ladipage_config option.

The ladipage_config option stores various plugin settings, including potentially sensitive data such as API keys, custom CSS/JS, or page configurations. By manipulating this option, an attacker could:

• Inject malicious JavaScript (stored XSS) that executes in the context of admin users.
• Alter plugin behavior to redirect traffic or exfiltrate data.
• Disable security features if configurable.

The attack is performed via a direct AJAX call or a crafted HTTP request to the WordPress admin-ajax.php endpoint with the appropriate action.

Vulnerable vs. Patched Code

Vulnerable Code (<= 4.4):

function save_config() {
    // No capability check
    if (isset($_POST['ladipage_config'])) {
        update_option('ladipage_config', $_POST['ladipage_config']);
    }
    wp_die();
}
add_action('wp_ajax_save_config', 'save_config');

Patched Code (Hypothetical):

function save_config() {
    // Added capability check
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized');
    }
    if (isset($_POST['ladipage_config'])) {
        update_option('ladipage_config', $_POST['ladipage_config']);
    }
    wp_die();
}
add_action('wp_ajax_save_config', 'save_config');

The patch adds a current_user_can('manage_options') check to ensure only administrators can modify the configuration.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress installation with LadiApp plugin version <= 4.4.
• Authenticated user account with subscriber-level access or higher.
• Valid nonce (if required by the plugin, though the vulnerability may bypass it).

Exploitation Steps:

1. Log in as a subscriber.
2. Obtain a valid WordPress nonce for the save_config action (if needed).
3. Send a POST request to /wp-admin/admin-ajax.php with the following parameters:
   • action=save_config
   • ladipage_config=<malicious_config>
4. The ladipage_config option will be updated.

Example cURL Command:

curl -X POST http://target.com/wp-admin/admin-ajax.php \
  -d "action=save_config&ladipage_config={\"evil_setting\":\"value\"}" \
  --cookie "wordpress_logged_in_<hash>=<session_cookie>"

Note: If a nonce is required, extract it from the page source or use a valid one.

Blue Team

Detection Steps:

1. Monitor for unauthorized changes to the ladipage_config option in the WordPress database.
2. Review logs for AJAX requests to admin-ajax.php with action=save_config from low-privilege users.
3. Implement file integrity monitoring for the plugin directory.

Honeypot Setup:

• Create a fake ladipage_config option with a known value and alert on any changes.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/ladipage/ladipage.php (or similar main plugin file)
• Database Option: ladipage_config modified unexpectedly
• Log Entry: POST to /wp-admin/admin-ajax.php with action=save_config from non-admin user
• Network: HTTP requests containing ladipage_config parameter from authenticated sessions

Detection Engineering

YARA Rule

rule CVE_2023_4627_LadiApp_Config_Modification {
    meta:
        description = "Detects attempts to exploit CVE-2023-4627 in LadiApp plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2023-4627"
    strings:
        $ajax_action = "save_config"
        $config_param = "ladipage_config"
    condition:
        $ajax_action and $config_param
}

Sigma Rule

title: CVE-2023-4627 LadiApp Unauthorized Config Modification
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects unauthorized modification of ladipage_config via AJAX
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=save_config'
        cs-uri-query|contains: 'ladipage_config'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-4627 LadiApp Unauthorized Config Modification"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=save_config"; http_client_body; content:"ladipage_config"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the LadiApp plugin until a patch is available.
2. Restrict user roles – Ensure only administrators have access to the plugin settings.
3. Web Application Firewall (WAF) – Create rules to block requests to admin-ajax.php with action=save_config from non-admin users.

Long-term Fix:

• Apply the patch as described in the Vulnerable vs. Patched Code section.
• Monitor the plugin vendor for an official update.

Workaround:

• Add a custom capability check via a WordPress plugin or theme functions.php:

add_action('wp_ajax_save_config', function() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized');
    }
}, 1);

Valters IT
Securing Digital Frontiers