CVE-2025-68579

Executive Summary

CVE-2025-68579 is a Missing Authorization vulnerability in the FV Simpler SEO WordPress plugin (slug: fv-all-in-one-seo-pack) developed by FolioVision. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized access to sensitive SEO-related data or configuration settings. The vulnerability affects all versions from n/a through 1.9.6. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating a very low probability of exploitation in the wild at this time, but the risk remains due to the lack of a patch.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress Plugin Directory. Users who have installed the plugin from the directory are at risk. The plugin is not available on NPM, PyPI, Go, or Ruby registries. The supply chain risk is moderate, as the plugin is directly maintained by FolioVision, but the lack of a patch increases the attack surface for WordPress sites using this plugin.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector (AV): Network – The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low – No special conditions or complex attack sequences are required.
• Privileges Required (PR): None – No authentication is needed to exploit the flaw.
• User Interaction (UI): None – The attacker does not need to trick a user into performing any action.
• Scope (S): Unchanged – The exploit cannot affect resources beyond the vulnerable component.
• Confidentiality (C): Low – Limited information disclosure is possible.
• Integrity (I): None – No data modification is possible.
• Availability (A): None – No denial-of-service impact.

Threat Level: Medium. The vulnerability is easy to exploit but has limited impact (only confidentiality). However, the lack of a patch and the potential for chaining with other vulnerabilities could elevate the risk.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check in the FV Simpler SEO plugin. In WordPress, plugins often register AJAX actions or REST API endpoints that should be protected by capability checks (e.g., manage_options). In this case, the plugin fails to verify that the requesting user has the necessary permissions before executing sensitive operations.

Root Cause: The plugin likely uses wp_ajax_* or wp_ajax_nopriv_* hooks without proper nonce verification or capability checks. This allows any unauthenticated user to call these endpoints and potentially read SEO metadata, configuration options, or other sensitive data.

Attack Vector: An attacker can craft a simple HTTP request to the vulnerable endpoint, bypassing authentication. For example, if the plugin exposes a REST API route like /wp-json/fv-seo/v1/settings, an unauthenticated GET request could return the plugin’s configuration, including API keys or internal settings.

Impact: The primary impact is information disclosure. An attacker could extract SEO settings, which might include database prefixes, API keys for third-party services, or other sensitive data that could be used in further attacks.

Vulnerable vs. Patched Code

Since no patch is available, we can only hypothesize the vulnerable code pattern. A typical vulnerable snippet might look like:

Vulnerable Code (hypothetical):

add_action('wp_ajax_nopriv_fv_seo_get_settings', 'fv_seo_get_settings');
function fv_seo_get_settings() {
    // No capability check or nonce verification
    $settings = get_option('fv_seo_settings');
    wp_send_json($settings);
}

Patched Code (hypothetical):

add_action('wp_ajax_fv_seo_get_settings', 'fv_seo_get_settings');
function fv_seo_get_settings() {
    // Check if user has admin capabilities
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    // Verify nonce
    if (!wp_verify_nonce($_REQUEST['_wpnonce'], 'fv_seo_nonce')) {
        wp_die('Nonce verification failed', 403);
    }
    $settings = get_option('fv_seo_settings');
    wp_send_json($settings);
}

The patched version removes the nopriv_ prefix (which allows unauthenticated access) and adds capability and nonce checks.

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• A WordPress site with FV Simpler SEO version <= 1.9.6 installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify the vulnerable endpoint. Common patterns include:
   • /wp-admin/admin-ajax.php?action=fv_seo_get_settings
   • /wp-json/fv-seo/v1/settings
2. Send a crafted HTTP request using curl:

   curl -X GET "http://target.com/wp-admin/admin-ajax.php?action=fv_seo_get_settings"
   

3. If the endpoint returns data without authentication, the vulnerability is confirmed.

Expected Output: The response may contain JSON-encoded SEO settings, including sensitive information.

Blue Team (Defender)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with actions prefixed by fv_ or fv_seo_.
• Look for requests from unauthenticated users to endpoints that should require authentication.

Hunting:

• Search logs for patterns like action=fv_seo_ in admin-ajax.php requests.
• Use the following Sigma rule to detect exploitation attempts.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /wp-admin/admin-ajax.php with parameter action=fv_seo_get_settings (or similar).
  • Unauthenticated GET requests to /wp-json/fv-seo/v1/* endpoints.
• File IOCs:
  • Plugin file: /wp-content/plugins/fv-all-in-one-seo-pack/fv-all-in-one-seo-pack.php
  • Version string in plugin header: Version: 1.9.6 or lower.
• Log IOCs:
  • Web server logs showing 200 responses to unauthenticated AJAX requests with fv_seo_ action.

Detection Engineering

YARA Rule

rule CVE_2025_68579_FV_Simpler_SEO_Missing_Auth {
    meta:
        description = "Detects FV Simpler SEO plugin files with missing authorization vulnerability"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-68579"
        hash = "unknown"
    strings:
        $vuln_func = "wp_ajax_nopriv_" nocase
        $plugin_slug = "fv-all-in-one-seo-pack" nocase
        $version_low = "Version: 1.9.6" nocase
    condition:
        $plugin_slug and $vuln_func and $version_low
}

Sigma Rule

title: CVE-2025-68579 - FV Simpler SEO Missing Authorization Exploitation
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated AJAX requests to FV Simpler SEO plugin endpoints
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-68579
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'action=fv_seo_'
        c-ip: '127.0.0.1'  # Replace with external IP range
    condition: selection
falsepositives:
    - Legitimate admin users accessing the plugin settings
level: medium
tags:
    - attack.initial_access
    - attack.t1190

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-68579 - FV Simpler SEO Missing Authorization Exploitation";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=fv_seo_"; http_uri;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-68579;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until an official patch is released.
2. Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with action=fv_seo_* from unauthenticated users.
3. Monitor logs for any exploitation attempts.

Long-term Fix:

• Apply the vendor patch once available.
• If the plugin is no longer maintained, consider replacing it with an alternative SEO plugin that is actively supported.

Workaround:

• Add the following code to the theme's functions.php to block unauthenticated access to the vulnerable endpoints:

  add_action('init', function() {
      if (defined('DOING_AJAX') && DOING_AJAX && !is_user_logged_in()) {
          $action = $_REQUEST['action'] ?? '';
          if (strpos($action, 'fv_seo_') === 0) {
              wp_die('Unauthorized', 403);
          }
      }
  });
  

Valters IT
Securing Digital Frontiers