CVE-2024-54242

Executive Summary

CVE-2024-54242 is a Missing Authorization vulnerability in the Simple Notification WordPress plugin (versions <= 1.3) developed by Appsbd. This flaw allows authenticated attackers with low privileges to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access, modification, or limited system disruption. The vulnerability has a CVSS score of 6.5 (Medium) and an EPSS score of 0.0%, indicating low exploitation likelihood at this time. No public proof-of-concept (PoC) or exploit code has been released, and no official patch is available. As a WordPress plugin vulnerability, it directly impacts the WordPress ecosystem and does not involve Apache or Nginx server software.

Supply Chain & Package Security

This vulnerability affects the Simple Notification WordPress plugin, distributed via the official WordPress plugin repository. Users who installed the plugin directly from the WordPress dashboard or via manual upload are affected. No known supply chain compromise has been reported, but the lack of a patch increases the risk of malicious actors forking or distributing modified versions.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): Low (L) – Attacker needs authenticated access with low privileges.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – Exploit does not affect other components.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited data modification.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: Medium. While the CVSS score is 6.5, the lack of public exploits and low EPSS score reduce immediate risk. However, the absence of a patch means any discovered exploit could be used without mitigation.

Deep Dive & Mechanics

The vulnerability resides in the Simple Notification plugin's access control implementation. The plugin fails to properly validate user capabilities when processing AJAX requests or REST API endpoints. Specifically, the check_admin_referer() or current_user_can() functions are either missing or incorrectly implemented, allowing users with low-level roles (e.g., Subscriber) to perform actions intended for administrators or editors.

The flaw is triggered by sending crafted HTTP requests to the plugin's administrative endpoints. For example, an attacker could modify notification settings, delete existing notifications, or create new ones without proper authorization. The plugin's code likely uses wp_ajax_* hooks without verifying the manage_options capability.

Vulnerable vs. Patched Code

Vulnerable Code (version <= 1.3):

add_action('wp_ajax_simple_notification_save', 'simple_notification_save');
function simple_notification_save() {
    // Missing capability check
    update_option('simple_notification_settings', $_POST['settings']);
    wp_die();
}

Patched Code (hypothetical):

add_action('wp_ajax_simple_notification_save', 'simple_notification_save');
function simple_notification_save() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    update_option('simple_notification_settings', $_POST['settings']);
    wp_die();
}

The patched version adds a current_user_can('manage_options') check to ensure only administrators can modify settings.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress installation with Simple Notification plugin <= 1.3.
• Low-privileged user account (e.g., Subscriber).

Exploitation Steps:

1. Log in as a low-privileged user.
2. Craft a POST request to the vulnerable AJAX endpoint:

   POST /wp-admin/admin-ajax.php HTTP/1.1
   Host: target-site.com
   Content-Type: application/x-www-form-urlencoded
   Cookie: [valid session cookie]
   
   action=simple_notification_save&settings[message]=malicious
   

3. The plugin processes the request without checking capabilities, allowing unauthorized modification of notification settings.

Note: No public exploit code is available; this is a conceptual demonstration.

Blue Team

Detection:

• Monitor for AJAX requests to admin-ajax.php with action=simple_notification_* from low-privileged users.
• Alert on changes to the simple_notification_settings option in the database.

Hunting:

• Search for unauthorized modifications to notification settings via database queries:

  SELECT * FROM wp_options WHERE option_name = 'simple_notification_settings';
  

• Review WordPress logs for unusual AJAX activity.

Indicators of Compromise (IOCs)

• Network: HTTP POST requests to /wp-admin/admin-ajax.php with action=simple_notification_save or similar.
• File: Modified simple-notification.php or related plugin files.
• Database: Unauthorized changes to wp_options table, specifically simple_notification_settings.
• Log: WordPress debug log entries showing AJAX calls from unexpected user roles.

Detection Engineering

YARA Rule

rule detect_simple_notification_missing_auth {
    meta:
        description = "Detects CVE-2024-54242 exploitation attempts in HTTP requests"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2024-54242"
    strings:
        $ajax_action = "action=simple_notification_save"
        $wp_ajax = "wp_ajax_simple_notification"
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-54242 - Simple Notification Missing Authorization
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects exploitation attempts of CVE-2024-54242
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=simple_notification_save'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2024-54242 - Simple Notification Missing Authorization Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/wp-admin/admin-ajax.php";
    http_uri;
    content:"action=simple_notification_save";
    http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available.
2. Restrict user roles – Ensure only trusted administrators have access.
3. Implement Web Application Firewall (WAF) rules to block unauthorized AJAX requests.

Long-term Fix:

• Apply the patched code manually (see Vulnerable vs. Patched Code section) or wait for an official update from the vendor.
• Monitor the WordPress plugin repository for updates.

Workaround:

• Add a custom capability check via a mu-plugin:

  add_action('wp_ajax_simple_notification_save', function() {
      if (!current_user_can('manage_options')) {
          wp_die('Unauthorized', 403);
      }
  }, 1);
  

Valters IT
Securing Digital Frontiers