CVE-2025-49396

Executive Summary

CVE-2025-49396 is a Missing Authorization vulnerability in the Themify Builder WordPress plugin, affecting versions up to and including 7.6.7. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized actions within the WordPress ecosystem. The vulnerability has a CVSS score of 4.3 (Medium) and currently has no known public exploit or patch. The EPSS score is 0.0%, indicating low exploitation likelihood at this time, but the risk remains due to the widespread use of the plugin.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor for updates from the vendor (Themifyme) and apply patches as soon as they become available. No known supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
• Base Score: 4.3 (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: None (C:N)
• Integrity Impact: Low (I:L)
• Availability Impact: None (A:N)

Threat Level: Medium. The vulnerability allows unauthorized access to certain functions but does not directly lead to data theft or system compromise. However, it could be chained with other vulnerabilities for more severe impact.

Deep Dive & Mechanics

The vulnerability resides in the Themify Builder plugin's access control mechanisms. The plugin fails to properly validate user permissions before allowing access to certain administrative or builder-related functions. This is a classic Missing Authorization (CWE-862) issue.

Root Cause: The plugin does not enforce capability checks (e.g., current_user_can()) on specific AJAX actions or REST API endpoints, allowing unauthenticated users to trigger actions that should be restricted to authenticated users with specific roles (e.g., editor, administrator).

Attack Vector: An attacker can send crafted HTTP requests to the vulnerable endpoints without authentication. The low complexity and no required privileges make this easily exploitable.

Impact: An attacker could potentially modify builder settings, inject malicious content, or perform other unauthorized actions that affect the integrity of the WordPress site. The exact impact depends on the specific unprotected functions.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on common fixes for such vulnerabilities.

Vulnerable Code (Example):

// In a Themify Builder AJAX handler
add_action('wp_ajax_themify_builder_save', 'themify_builder_save');
add_action('wp_ajax_nopriv_themify_builder_save', 'themify_builder_save'); // Missing capability check

function themify_builder_save() {
    // Process save without checking user capabilities
    update_option('themify_builder_data', $_POST['data']);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_themify_builder_save', 'themify_builder_save');
// Remove the nopriv action to require authentication
// add_action('wp_ajax_nopriv_themify_builder_save', 'themify_builder_save');

function themify_builder_save() {
    // Add capability check
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    // Process save
    update_option('themify_builder_data', $_POST['data']);
    wp_die();
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Themify Builder <= 7.6.7 installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify vulnerable endpoints (e.g., AJAX actions like themify_builder_save, themify_builder_load, etc.).
2. Send a crafted HTTP request to the endpoint without authentication.

Example Request (using cURL):

curl -X POST https://target.com/wp-admin/admin-ajax.php \
  -d 'action=themify_builder_save&data=malicious_content'

Expected Outcome: The request is processed without authentication, potentially modifying site data.

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with actions related to Themify Builder from unauthenticated users.
• Look for patterns in web server logs indicating repeated attempts to access builder endpoints without a valid session.

Defense:

• Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to known Themify Builder AJAX actions.
• Apply the principle of least privilege by ensuring all AJAX handlers check user capabilities.
• Temporarily disable the plugin if no patch is available and the risk is deemed high.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP POST requests to /wp-admin/admin-ajax.php with action=themify_builder_* parameters from unauthenticated sources.
  • Unusual patterns in action parameter values (e.g., themify_builder_save, themify_builder_load).

• File IOCs:

  • Modified wp_options table entries related to themify_builder_data.
  • Unexpected files in the uploads directory if the builder allows file operations.

• Log IOCs:

  • Web server logs showing 200 responses to AJAX requests without prior authentication.
  • PHP error logs indicating missing capability checks.

Detection Engineering

YARA Rule

rule Detect_Themify_Builder_Missing_Auth {
    meta:
        description = "Detects attempts to exploit CVE-2025-49396 in Themify Builder"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-49396"
    strings:
        $ajax_action = "themify_builder_" nocase
        $admin_ajax = "admin-ajax.php" nocase
    condition:
        $admin_ajax and $ajax_action
}

Sigma Rule

title: Detect Themify Builder Missing Authorization Exploitation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated requests to Themify Builder AJAX endpoints
author: Valters IT
date: 2025/04/10
references:
    - CVE-2025-49396
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=themify_builder_'
    condition: selection
falsepositives:
    - Legitimate authenticated requests (if not filtered by session)
level: medium

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-49396 - Themify Builder Missing Authorization Exploit Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=themify_builder_"; http_client_body;
    classtype:attempted-admin;
    sid:10000001;
    rev:1;
    reference:cve,2025-49396;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if it is not critical to operations until a patch is available.
2. Implement a WAF rule to block unauthenticated requests to admin-ajax.php with action parameters starting with themify_builder_.
3. Monitor logs for any signs of exploitation.

Long-term Fix:

• Apply the official patch from Themifyme once released.
• If you are a developer, add capability checks to all AJAX handlers:

  if (!current_user_can('edit_posts')) {
      wp_die('Unauthorized', 403);
  }
  

• Regularly update all WordPress plugins and themes.

Workaround:

• Use a security plugin like Wordfence to add virtual patching for this vulnerability.

Valters IT