Church Admin plugin (≤ 5.0.26) — Broken Access Control (CVE-2025-57896): What site owners must do now

Published: 2025-08-22 — Author: Hong Kong Security Expert

TL;DR

As a Hong Kong security practitioner with hands-on WordPress operations experience, my assessment: a broken access control bug in Church Admin (≤ 5.0.26), tracked as CVE-2025-57896, allows unauthenticated requests to trigger actions that should be privileged. The vendor fixed the issue in 5.0.27. The CVSS is modest (5.3), but unauthenticated access increases the chance of automated exploitation. Immediate priorities:

• Update Church Admin to 5.0.27 or later immediately.
• If you cannot update right away, apply short-term mitigations (disable the plugin, restrict access to plugin endpoints, or deploy defensive rules at the server/WAF level).
• Scan for indicators of compromise and follow an incident response checklist if you see suspicious activity.
• Use virtual patching or server-level rules as a temporary barrier until all sites are patched.

Overview of the issue

What happened

• A broken access control vulnerability was disclosed affecting Church Admin plugin releases up to and including 5.0.26.
• Unauthenticated actors can invoke functionality that should require authentication or privileges.
• The vendor released a fix in version 5.0.27. The issue is tracked as CVE-2025-57896 and was publicly disclosed in August 2025.

Why this matters

Broken access control often stems from missing capability checks on REST endpoints, AJAX actions, or direct plugin files. Even when a CVSS score is not high, unauthenticated exposure enables mass scanning and opportunistic exploitation.

Who is affected

Any WordPress site running Church Admin ≤ 5.0.26. Even dormant installations can be targeted if endpoints are reachable.

Fixed version

Upgrade to Church Admin 5.0.27 or later to remove the vulnerable code paths.

Technical summary (non-vendor, practical)

Vulnerability class

Broken access control: missing or insufficient authorization/authentication checks. Common manifestations include absent current_user_can() checks, missing nonce verification for state-changing actions, and unsecured REST/AJAX endpoints.

Exploitation vector (likely)

Unauthenticated HTTP requests targeting plugin endpoints (admin-ajax.php actions, REST API routes, or direct plugin files) that perform privileged operations. Automated scanners can detect the plugin and probe known endpoints.

Impact

• Unauthorized modification of plugin-managed data (events, people records, settings).
• Creation/modification of database entries or disclosure of sensitive information.
• Possible pivot to plant malicious payloads or create admin accounts if chained with other flaws.

The published CVSS is 5.3 — significant but not a guaranteed full-site takeover without additional issues.

Immediate actions (first 6–24 hours)

1. Update the plugin. Install Church Admin 5.0.27 or later and verify versions across all sites. Prioritize public-facing sites.
2. If you cannot update immediately — apply temporary mitigations:
   • Disable the plugin until you can upgrade.
   • Restrict public access to the plugin directory and known endpoints with web server rules (examples below).
   • Deploy server-level or WAF rules that block requests to plugin paths, suspicious parameters, or unauthenticated access patterns.
3. Block or rate-limit unauthenticated access to admin-ajax and REST endpoints where possible. Rate limiting reduces automated scanning and exploitation.
4. Scan and monitor for signs of exploitation: review access logs, WordPress activity logs, and look for unusual admin-ajax.php requests, new admin users, database changes, scheduled tasks, or unexpected file changes.

Useful server / WAF rules you can apply right now

Test all rules on staging before rolling out to production. The rules below are defensive and intended only as temporary mitigations; adjust patterns when you identify exact vulnerable endpoints.

Apache (.htaccess) — block direct access to plugin files for unauthenticated users

<IfModule mod_rewrite.c>
  RewriteEngine On

  # Deny requests to plugin files unless from admin IP(s)
  RewriteCond %{REQUEST_URI} ^/wp-content/plugins/church-admin [NC]
  # Allow from trusted admin IP (replace with your IP)
  RewriteCond %{REMOTE_ADDR} !^203\.0\.113\.45$
  RewriteRule ^ - [F,L]
</IfModule>

Nginx — deny or return 403 for plugin folder for public IPs

location ~* /wp-content/plugins/church-admin/ {
    allow 203.0.113.45;  # replace with your admin IP
    deny all;
    return 403;
}

Generic ModSecurity (OWASP CRS style) — block suspicious requests

SecRule REQUEST_FILENAME|REQUEST_URI "@rx (church-admin|churchadmin)" "id:1001001,phase:1,deny,log,status:403,msg:'Block possible Church Admin exploit - unauthenticated access'"
# Or block admin-ajax calls without WP login cookie
SecRule REQUEST_URI "@contains admin-ajax.php" "phase:1,chain,deny,log,status:403,id:1001002,msg:'Block admin-ajax unauthenticated calls related to Church Admin'"
  SecRule &REQUEST_HEADERS:Cookie "@eq 0"

WordPress-level PHP filter (temporary mu-plugin)

As a temporary measure, add an mu-plugin to block unauthenticated attempts to call known Church Admin actions. Remove this after updating.

<?php
// Temporary: block unauthenticated requests attempting to call Church Admin actions.
// Customize the $blocked_actions array when you know the action names.
add_action('admin_init', function() {
    if ( defined('DOING_AJAX') && DOING_AJAX ) {
        $action = isset($_REQUEST['action']) ? $_REQUEST['action'] : '';
        $blocked_actions = array('ca_export', 'ca_import', 'church_admin_action'); // example action names
        if ( in_array($action, $blocked_actions, true) && ! is_user_logged_in() ) {
            status_header(403);
            wp_die('Forbidden', 'Forbidden', array('response' => 403));
        }
    }
});

Warning: use only temporarily and verify action names before blocking. Incorrect rules can break legitimate functionality.

How to detect whether you were targeted or exploited

Search logs and WordPress state for these indicators:

• Web server access logs: repeated requests to /wp-content/plugins/church-admin/, admin-ajax.php, or /wp-json/ endpoints with church-admin related parameters; spikes in requests from unknown IPs.
• WordPress database & site changes: unexpected admin users, modified plugin-managed records, unauthorized changes to settings, or new scheduled tasks.
• Filesystem indicators: new or modified files under uploads, plugin directories, or mu-plugins; web shells or unfamiliar PHP files.
• Behavior & UX: odd plugin behavior, outbound network connections from PHP processes, or malware scanner alerts.

Recommended detection steps

• Export webserver logs and grep for “church-admin”, “admin-ajax.php” with suspicious actions, and POSTs to plugin paths.
• Review wp_users, wp_usermeta, and plugin-specific tables for new or modified accounts/data.
• Use file integrity checks and compare files against known-good copies or backups.

If you find indicators of compromise: isolate the site, collect logs, and follow the incident response steps below.

Incident response checklist

1. Isolate and preserve
   • Take the site offline temporarily to limit further damage.
   • Preserve webserver logs, database dumps, and filesystem snapshots.
2. Contain
   • Disable the vulnerable plugin immediately.
   • Reset WordPress admin passwords and rotate any credentials potentially exposed.
   • Revoke and rotate API keys if the plugin had external integrations.
3. Eradicate
   • Remove backdoors and malicious files. Prefer rebuild from clean backups where possible.
   • Replace modified core/plugin/theme files with vendor-provided originals.
   • Reinstall the patched plugin (5.0.27 or later) only after confirming the site is clean.
4. Recover
   • Restore from clean backups if necessary, update core/themes/plugins, and verify functionality.
   • Harden access controls (strong passwords, consider 2FA for admin accounts, limit login attempts).
5. Post-incident
   • Perform a thorough audit to confirm no residual footholds.
   • Review logs for lateral movement or data exfiltration.
   • Document the incident and update patching and response playbooks.

If you lack in-house forensic capabilities, engage experienced incident responders.

Long-term remediation & secure coding guidance for plugin developers

For developers and maintainers, a proper fix requires secure design and code hygiene:

1. Enforce capability checks — use current_user_can() for state-changing actions.
2. Verify nonces — use wp_verify_nonce() for AJAX and form submissions, combined with capability checks.
3. Protect REST API endpoints — use permission_callback in register_rest_route() to restrict access appropriately.
4. Principle of least privilege — separate public read-only endpoints from write operations and protect the latter.
5. Input validation and output escaping — validate, sanitize, and escape all inputs and outputs.
6. Testing & code review — add automated tests to assert endpoints require authentication; include threat modelling and manual review for sensitive code paths.
7. Disclosure and patching process — maintain a responsible disclosure process and publish clear upgrade instructions.

Why virtual patching or server rules are useful while you update

Many organisations delay updates for compatibility or operational reasons. Virtual patching via server/WAF rules gives immediate, temporary mitigation against known exploit patterns and reduces the risk window. Benefits:

• Immediate protection against known exploit attempts without altering application code.
• Centralised deployment for environments managing multiple sites.
• Ability to block unauthenticated requests targeting plugin endpoints.

Limitations: virtual patches are temporary. They must be used alongside timely vendor patches, backups, and monitoring.

Suggested detection rules (SIEM / log monitoring)

Add the following detections to a SIEM or central log store:

• Repeated POST requests to /wp-content/plugins/church-admin/ or to /wp-admin/admin-ajax.php with suspicious action parameters.
• High rate of requests to admin-ajax.php or /wp-json/* without WordPress auth cookies.
• Unusual creation of administrator or editor accounts.
• New files in plugin directories or mu-plugins outside normal deploys.
• Database writes to plugin-specific tables without an authenticated session.

Example Elasticsearch/Kibana filter:

request_uri.keyword:("/wp-content/plugins/church-admin/*" OR "/wp-admin/admin-ajax.php")
AND http_method:("POST" OR "GET")
AND NOT request_headers.cookie:*wordpress_logged_in*

How to verify you fixed the issue

1. Confirm plugin version is 5.0.27 or later on all sites.
2. Re-run active scans with trusted internal tools or validated external services.
3. Verify server/WAF logs show blocked exploit attempts if temporary rules were used.
4. Conduct smoke tests for plugin features (forms, exports/imports, REST endpoints).
5. Monitor logs for at least two weeks for late attempts or chained activity.

Hardening checklist to reduce future risk

• Keep WordPress core, themes, and plugins up-to-date via a tested update process.
• Apply least privilege to user accounts and service credentials.
• Limit plugin installations to vetted, actively maintained projects.
• Enforce strong admin credentials and enable two-factor authentication where feasible.
• Use file integrity monitoring and maintain regular offline backups.
• Implement rate-limiting and bot protection for sensitive endpoints.
• Maintain centralized logging and alerting for suspicious changes.

Sample message you can share with clients or site editors

Suggested short message for clients:

We identified a security vulnerability in the Church Admin plugin (versions ≤5.0.26) that could allow unauthenticated actors to perform privileged actions. We will update affected sites to the patched version 5.0.27 and have applied temporary protections where needed. No evidence of exploitation has been found to date. Please contact us if you observe unexpected site behaviour.

Final notes and next steps (quick checklist)

• Update Church Admin to 5.0.27 or later as the highest priority.
• If you cannot update immediately: disable the plugin, restrict access to plugin endpoints, or deploy server/WAF rules.
• Scan logs and system state for signs of exploitation and follow incident response procedures if needed.
• Use virtual patching or server rules to reduce exposure until updates are applied.
• Review and improve plugin and site hardening practices to reduce future risk.

References & resources

• CVE-2025-57896 — Church Admin vulnerability
• WordPress developer docs: current_user_can(), wp_verify_nonce(), register_rest_route() permission_callback
• OWASP Top 10 — guidance on access control and injection risks