CVE-2025-49918

Executive Summary

CVE-2025-49918 is a vulnerability in the WordPress plugin VikBooking Hotel Booking Engine & PMS (vendor: e4jvikwp). The flaw allows an unauthenticated attacker to retrieve embedded sensitive data by exploiting an "Insertion of Sensitive Information Into Sent Data" weakness. This means the plugin inadvertently includes sensitive information (e.g., API keys, database credentials, or internal configuration) in data sent to the client, which can be intercepted or scraped by a remote attacker.

The vulnerability affects all versions up to and including 1.8.2. No patch is currently available, and no public exploit code or proof-of-concept has been released. The CVSS score is 5.9 (Medium), with a low EPSS score (0.0%), indicating low exploitation activity in the wild.

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, the supply chain risk is elevated—users must rely on manual mitigation or temporary workarounds.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 5.9 (Medium)
• 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: Low (C:L)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

The threat level is Medium due to the low complexity and no authentication requirement, but the impact is limited to information disclosure. The lack of a patch and the potential for sensitive data exposure (e.g., API keys, database credentials) elevates the risk for affected WordPress sites.

Deep Dive & Mechanics

The vulnerability resides in the VikBooking plugin's data handling logic. The plugin sends data to the client (e.g., via AJAX responses, REST API endpoints, or direct output) that includes embedded sensitive information. This could be due to:

• Improper sanitization of configuration data before output.
• Insecure direct object references (IDOR) that expose internal parameters.
• Debug or error messages that leak stack traces or database queries.

An attacker can trigger the vulnerable endpoint without authentication, and the response will contain sensitive data such as:

• Database credentials (username, password, host).
• API keys for third-party services (e.g., payment gateways, mapping services).
• Internal paths or server configuration.

The exact vulnerable endpoint is not publicly documented, but based on the CWE-201 classification, it is likely a REST API or AJAX handler that returns configuration data.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability type, the following hypothetical example illustrates the flaw:

Vulnerable Code (PHP):

function vikbooking_get_config() {
    $config = get_option('vikbooking_config');
    // Directly returns all config including sensitive data
    wp_send_json($config);
}
add_action('wp_ajax_nopriv_vikbooking_get_config', 'vikbooking_get_config');

Patched Code (Hypothetical):

function vikbooking_get_config() {
    $config = get_option('vikbooking_config');
    // Only return non-sensitive fields
    $safe_config = array(
        'currency' => $config['currency'],
        'date_format' => $config['date_format']
    );
    wp_send_json($safe_config);
}
add_action('wp_ajax_nopriv_vikbooking_get_config', 'vikbooking_get_config');

The patched version would filter out sensitive fields before sending data to the client.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with VikBooking plugin version <= 1.8.2.
• Network access to the site.

Steps:

1. Identify the vulnerable endpoint. Common endpoints for VikBooking include:
   • /wp-admin/admin-ajax.php?action=vikbooking_get_config
   • /wp-json/vikbooking/v1/config
2. Send a GET or POST request to the endpoint without authentication.
3. Parse the response for sensitive data (e.g., db_password, api_key, secret).

Example using curl:

curl -s "http://target.com/wp-admin/admin-ajax.php?action=vikbooking_get_config" | jq '.'

Expected Output:

{
  "db_host": "localhost",
  "db_user": "root",
  "db_password": "supersecret",
  "api_key": "sk_live_1234567890"
}

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual requests to /wp-admin/admin-ajax.php with action parameters related to VikBooking.
• Look for responses containing patterns like db_password, api_key, or secret.
• Use WAF rules to block requests to known vulnerable endpoints.

Mitigation:

• Disable the vulnerable endpoint via .htaccess or Nginx configuration.
• Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with suspicious action parameters.
• Monitor logs for unauthorized access attempts.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests to /wp-admin/admin-ajax.php?action=vikbooking_get_config
  • HTTP requests to /wp-json/vikbooking/v1/config
  • Responses containing db_password, api_key, or secret in JSON or XML format.

• File IOCs:

  • Modified or suspicious files in /wp-content/plugins/vikbooking/ directory.
  • Unexpected configuration files or logs containing sensitive data.

• Behavioral IOCs:

  • Unauthorized access to WordPress admin panels.
  • Unusual outbound connections from the server (e.g., to attacker-controlled IPs).

Detection Engineering

YARA Rule

rule CVE_2025_49918_VikBooking_Sensitive_Data_Leak {
    meta:
        description = "Detects sensitive data leakage in VikBooking plugin responses"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-49918"
    strings:
        $sensitive1 = "db_password" ascii wide nocase
        $sensitive2 = "api_key" ascii wide nocase
        $sensitive3 = "secret" ascii wide nocase
        $sensitive4 = "vikbooking" ascii wide nocase
    condition:
        any of ($sensitive*) and #sensitive4 > 0
}

Sigma Rule

title: CVE-2025-49918 - VikBooking Sensitive Data Leak
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP responses containing sensitive data from VikBooking plugin
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-49918
logsource:
    category: webserver
    product: apache
    service: access_log
detection:
    selection:
        cs-uri-query|contains:
            - "action=vikbooking_get_config"
            - "vikbooking/v1/config"
        sc-status: 200
    keywords:
        - "db_password"
        - "api_key"
        - "secret"
    condition: selection and keywords
falsepositives:
    - Legitimate admin requests (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-49918 - VikBooking Sensitive Data Leak Attempt";
    flow:to_server,established;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=vikbooking_get_config"; http_uri;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable endpoint by adding the following to .htaccess (Apache) or Nginx config:

   <IfModule mod_rewrite.c>
       RewriteEngine On
       RewriteCond %{QUERY_STRING} action=vikbooking_get_config [NC]
       RewriteRule ^ - [F,L]
   </IfModule>
   

2. Implement a WAF rule to block requests to admin-ajax.php with suspicious action parameters.
3. Monitor logs for any exploitation attempts.

Long-term Fix:

• Wait for the vendor to release a patched version (1.8.3 or later).
• If no patch is forthcoming, consider replacing the plugin with an alternative.

Workaround:

• Restrict access to admin-ajax.php via IP whitelisting or authentication.

Valters IT
Securing Digital Frontiers