Pronamic Google Maps (<= 2.4.1) — Authenticated Contributor Stored XSS (CVE‑2025‑9352)

By Hong Kong Security Expert — 27 August 2025

Summary

• Vulnerability: Authenticated (Contributor+) Stored Cross‑Site Scripting (XSS)
• Affected software: Pronamic Google Maps plugin for WordPress — versions ≤ 2.4.1
• Fixed in: 2.4.2
• CVE: CVE‑2025‑9352
• Reported: 27 Aug 2025
• Required privilege: Contributor
• Business impact: persistent XSS that can result in session theft, content injection, phishing redirects, and site reputation/SEO damage
• Priority: update the plugin and apply virtual patching / WAF mitigations immediately for sites that cannot update at once

Introduction — why this matters

Stored XSS remains one of the most frequently exploited weaknesses in the WordPress ecosystem. In this case a Contributor-level account can store HTML/JavaScript within map-related fields in Pronamic Google Maps and that content may later be rendered to other users without proper escaping. The consequence is attacker-controlled script execution in the context of your site origin.

Although Contributors usually cannot publish, many sites display contributor content via previews, internal lists, or public embeds; these display paths are frequently sufficient to make stored XSS a reliable and impactful attack vector.

This post explains the vulnerability, realistic exploit scenarios, detection steps, remediation actions, immediate virtual-patch examples, and long-term hardening and incident response guidance from a Hong Kong security practitioner’s perspective.

Technical overview

What is stored XSS?

Stored (persistent) XSS happens when user-supplied data is saved server-side (database or filesystem) and later embedded into pages without proper output encoding. When a browser renders that malicious content, the script runs with the site’s origin privileges (cookies, same-origin access, etc.).

Where this plugin was vulnerable

The plugin exposes fields for map entries (titles, descriptions, marker labels, info-window content, shortcodes, and meta fields). In affected releases (≤ 2.4.1), one or more of these fields can be stored and later output without sufficient sanitization or escaping. A Contributor can create or edit a map entry with markup or JavaScript that becomes persistent in the site database and gets rendered to other users.

Likely vectors (examples)

• Map title or description fields that accept HTML and render on the front end.
• Marker labels or info-window content serialized to postmeta and later printed verbatim.
• Back-end listings where contributor entries are shown to editors/administrators without escaping.

Why Contributor privilege matters

Contributor accounts can create content and, while they typically cannot publish, many sites allow previews or direct rendering of contributor-created content. If contributor content is visible to higher-privilege users or to the public, stored XSS can be exploited to target those users.

Realistic exploitation scenarios

1. Public content injection
   A contributor adds a marker info window containing a script. When the map is embedded on a public page, visitors load and execute the script. Attackers can perform client-side redirects, inject adverts, or attempt data harvesting.
2. Administrative compromise
   A contributor saves content that appears in an admin list or preview viewed by an editor or admin. The script runs in the admin’s browser and can perform actions in that session (create users, change settings, install plugins) if the admin interacts while the script executes.
3. Phishing and targeted attacks
   Scripts can display fake admin dialogs to steal credentials or send forged requests to authenticated endpoints for data exfiltration.

Detecting whether you’re affected or exploited

1) Check plugin version

• WordPress Admin: Plugins → Installed Plugins → Pronamic Google Maps. If version ≤ 2.4.1, you are vulnerable.
• WP‑CLI: wp plugin list --status=active | grep pronamic-google-maps

2) Quick database search for suspicious HTML/JS

Run these queries from your hosting control panel or via WP‑CLI with appropriate DB access. Adjust table prefixes if you use custom prefixes.

-- Search wp_posts (post_content, post_title)
SELECT ID, post_type, post_title FROM wp_posts
WHERE post_content LIKE '%<script%' OR post_content LIKE '%javascript:%' OR post_title LIKE '%<script%';

-- Search wp_postmeta
SELECT post_id, meta_key, meta_value FROM wp_postmeta
WHERE meta_value LIKE '%<script%' OR meta_value LIKE '%onerror=%' OR meta_value LIKE '%onload=%';

-- Search for SVG/js handlers
SELECT * FROM wp_postmeta WHERE meta_value REGEXP '<svg|onload|onerror|javascript:';

3) Scan for injected content in the front end

• Crawl public pages and map embeds looking for script tags in map containers or marker info windows.
• Use curl to fetch rendered map pages and search for “<script” or “onerror=” patterns.

4) Check logs for suspicious admin UI POSTs

• Review web server access logs for POSTs to plugin endpoints, map save/edit AJAX calls, or wp-admin/post.php by contributor accounts around suspect times.
• Look for parameters containing <script or URL-encoded equivalents (%3Cscript%3E).

5) User role review

• Users → All Users → filter by Contributor. Confirm there are no unauthorized contributor accounts.

Immediate remediation (what to do now)

1. Update the plugin (recommended)
   Update Pronamic Google Maps to version 2.4.2 or later immediately — this is the primary fix.
2. If you cannot update immediately — apply virtual patching / WAF mitigation
   Deploy WAF rules to block requests that attempt to save map data containing script tags or event attributes. Virtual patching reduces risk while you plan and test the update.
3. Clean stored payloads
   After patching, search and remove stored payloads:
   • Remove script tags from post_content and post_meta entries found in detection steps.
   • Replace malicious values with sanitized text or restore from clean backups.
4. Harden accounts
   Temporarily restrict contributor accounts, remove unknown contributors, and force password resets for editors/admins who may have viewed malicious content.
5. Monitor for ongoing attacker activity
   Preserve logs and watch for suspicious requests, login attempts, or new user creation.

Suggested virtual patching — example WAF rules and guidance

Below are example patterns and rules you can adapt to your WAF or reverse proxy. Test all rules in logging/monitor mode before blocking to avoid false positives.

A. Generic request blocking rule (pseudo‑ModSecurity syntax)

SecRule REQUEST_METHOD "@streq POST" "chain,deny,status:403,id:100101,msg:'Block possible XSS in Pronamic Google Maps fields'"
  SecRule REQUEST_URI "@rx (pronamic|pronamic-google-maps|pronamic_maps|pronamic_gmaps|pronamic-google‑maps‑ajax)" "chain"
  SecRule ARGS|ARGS_NAMES|REQUEST_BODY "@rx (?:<\s*script\b|javascript:|onerror\s*=|onload\s*=|<svg\b|<img\b[^>]*onerror=)" "t:none,t:utf8tounicode,log,deny"

B. Narrow rule for contributor map save requests

SecRule ARGS:action "@streq pronamic_save_map" "chain,id:100102,deny,msg:'XSS attempt in map save action'"
  SecRule ARGS_NAMES|ARGS "@rx (?:<\s*script\b|javascript:|onerror\s*=|onload\s*=)" "log,deny"

C. Response filtering / output hardening (virtual escaping)

If you cannot update plugin code immediately, consider an output filter that sanitizes map content before it is rendered. Example mu-plugin (simplified):

<?php
// mu-plugin example: sanitize map outputs before rendering
add_filter('the_content', 'hk_sanitize_pronamic_map_outputs', 20);
function hk_sanitize_pronamic_map_outputs($content) {
  // Narrow: only sanitize map shortcodes or map container HTML
  if (strpos($content, 'pronamic_map') !== false) {
    // remove script tags and common event handlers
    $content = preg_replace('/<script\b[^>]*>.*?</script>/is', '', $content);
    $content = preg_replace('/on\w+\s*=\s*"([^"]*)"/is', '', $content);
  }
  return $content;
}
?>

D. Block common XSS payloads in input fields

On save actions, reject parameters that include “E. Allowlisting and rate limiting contributor actions

• If Contributors do not need HTML, strip HTML from map fields for that role; allow HTML only for Editors/Admins.
• Rate-limit submissions that include inline HTML from low‑privileged accounts.

WAF tuning tips

• Avoid overly broad blocking that breaks legitimate HTML or third‑party integrations.
• Use logging/alert mode for several days to tune patterns before enforcing blocks.
• Apply stricter checks to lower-privilege roles (Contributor/Author).
• Combine request filtering (prevent storage) with response filtering (prevent execution if stored).

Remediation checklist — step by step

1. Verify plugin version and update to 2.4.2 or later.
2. Quarantine suspicious content; consider putting the site into maintenance mode if exploitation is suspected.
3. Clean the database using the detection queries; export suspect rows, review offline, then update/delete.
4. Review user accounts: remove or demote unnecessary Contributors; check for unauthorized admin/editor accounts.
5. Rotate secrets and API keys if admin compromise is suspected (e.g., Google Maps API keys stored in options).
6. Re-scan the site (server + WordPress) and continue monitoring logs for anomalies.

Incident response — if you were hit

If you confirm exploitation, follow a containment → eradication → recovery workflow.

Containment

• Place the site into maintenance mode if possible.
• Disable the plugin temporarily if doing so will stop active payloads and not critically break the site.
• Revoke sessions for admin/editor users (force logout all sessions).

Eradication

• Remove injected content from database and filesystem.
• Reset passwords for privileged users (admin/editor) and remove suspicious accounts.
• Revoke and reissue any API keys that may have been exposed.

Recovery

• Restore from a clean backup taken before the compromise if available.
• Reapply plugin updates and WAF rules once clean.
• Harden accounts and policies to reduce the likelihood of recurrence.

Post‑incident actions

• Document a timeline, indicators of compromise, and cleanup performed.
• Notify impacted users if personal data may have been exposed and comply with local breach notification laws.
• Perform a root cause analysis and update processes to reduce repeat exposures.

Hardening and prevention — beyond the immediate fix

• Least privilege and role management: limit Contributor capabilities and consider custom roles for map management.
• Sanitize and escape: developers should sanitize on input and escape on output (esc_html(), esc_attr(), wp_kses_post() as appropriate).
• Plugin lifecycle and vetting: use actively maintained plugins and test updates in staging before production.
• Automated scanning and monitoring: schedule scans for stored XSS indicators and monitor file integrity and database changes.
• Backups and rollback planning: maintain regular backups (database + files) and verify restore procedures.
• Virtual patching: WAF rules can reduce exposure between disclosure and patch deployment.

Detection playbook you can run today

• Run the SQL queries above to find likely stored payloads.
• Crawl pages with maps and search for “<script”, “onerror=”, “javascript:” and other indicators.
• Export suspicious rows for offline review before applying changes to the live DB.
• Block incoming requests that try to store scripts from low-privilege accounts via WAF or application-layer validation.

Example search and clean process (WP‑CLI + MySQL)

1. Export suspicious entries:

   wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%<script%';" > suspicious_posts.txt

2. Sanitize confirmed rows (example using REGEXP_REPLACE if available):

   wp db query "UPDATE wp_posts SET post_content = REGEXP_REPLACE(post_content, '<script[^>]*>.*?</script>', '') WHERE post_content REGEXP '<script';"

   Note: REGEXP_REPLACE availability depends on MySQL version. If unavailable, export, clean locally, and import. Always take a full DB dump before changes:

   wp db export before_clean.sql

Communication and disclosure considerations

• Operators who discover abuse should prioritize containment and cleanup, and comply with local breach notification requirements if user data was exposed.
• Plugin authors should publish advisories, provide a fixed release, and offer clear upgrade guidance for site owners.

User education — reduce social engineering effectiveness

• Train editors/admins to be cautious about approving content from unknown contributors.
• Use 2FA for all accounts with publishing capabilities (Editor/Admin).

Conclusion and immediate action plan (next 24–72 hours)

0–24 hours

• Verify whether Pronamic Google Maps is installed and whether version ≤ 2.4.1 is active.
• If vulnerable, update to 2.4.2 immediately.
• If you cannot update at once, enable WAF rules as described and restrict contributor capabilities where possible.

24–72 hours

• Run the detection queries and sanitize any stored payloads (take full DB backups first).
• Review and clean suspicious user accounts; force password resets for privileged users if necessary.
• Continue monitoring logs for abnormal activity and enable alerts for plugin endpoints.

Ongoing

• Adopt layered defenses: patching, access controls, runtime protections (WAF), logging, scanning, and backups.
• Keep plugins and WordPress core updated and maintain regular backups and tested restore processes.

Final notes

Stored XSS is deceptively simple to introduce and can have significant impact. Two levers reduce risk most effectively: fast patching and runtime protections. Combine prompt updates with targeted WAF rules and careful cleanup to close attacker windows quickly. If you require hands-on assistance, consult a trusted security professional who can help implement detection, cleanup, and prevention measures tailored to your environment.

Stay vigilant, enforce least privilege, and ensure contributor content paths are treated with rigorous sanitization and monitoring.