Nombre del complemento	Event List
Type of Vulnerability	Escalada de privilegios
CVE Number	CVE-2025-6366
Urgencia	Alto
CVE Publish Date	2025-08-25
Source URL	CVE-2025-6366

Urgent: Event List plugin (<= 2.0.4) — Authenticated Subscriber Privilege Escalation (CVE-2025-6366) — What WordPress Site Owners Must Do Now

Fecha: 2025-08-25

Autor: WP-Firewall Security Team

Resumen: A high-severity privilege escalation vulnerability (CVE-2025-6366) affecting the Event List WordPress plugin (versions <= 2.0.4) allows authenticated users with Subscriber-level access to escalate their privileges. This post explains the risk, safe detection approaches, practical mitigation (including immediate and temporary measures), incident response steps, and recommended long-term hardening. If you run WordPress sites, read this now and prioritize action.

Why this matters (plain language)

This vulnerability lets a low-privileged user — someone with a Subscriber account — perform actions they shouldn’t be able to do. In the worst case an attacker can use a compromised Subscriber account (or create one if your site allows registrations) and leverage the plugin flaw to gain higher privileges, potentially an administrator account. Once an account has administrator privileges, the attacker can install backdoors, create persistent admin users, tamper with content, or pivot to other systems.

The risk is rated high (CVSS 8.8) and this classifies under OWASP A7 (Identification and Authentication Failures). The plugin author released a fix in version 2.0.5. If you cannot immediately update, there are practical mitigations you can apply to reduce exposure.

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A short, responsible- disclosure note

We will not publish proof-of-concept exploit code or step-by-step attack payloads. Doing so would increase the risk to unpatched sites. Instead, this article focuses on detection, mitigation, and recovery for site owners and administrators.

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Affected software and available fix

• Affected plugin: Event List (WordPress plugin)
• Versiones vulnerables: <= 2.0.4
• Fijo en: 2.0.5
• CVE: CVE-2025-6366
• Required attacker privilege: Subscriber (authenticated)

Action required: Update the plugin to 2.0.5 (or later) immediately. If you have sites where you cannot update right away, apply the temporary mitigations listed below.

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Immediate steps (first 60–120 minutes)

1. Prioritize updating:
   • Update Event List plugin to 2.0.5 or later on all sites immediately. This is the single most effective action.
2. If you cannot update immediately:
   • Temporarily deactivate the Event List plugin on public-facing sites where you suspect the risk is unacceptable.
   • If the plugin must remain active and you have a web application firewall (WAF), enable virtual rules or block patterns described below (see “WAF / virtual patching”).
3. Audit recent account activity:
   • Look for newly created users, suspicious role changes, or recent logins for Subscribers at odd hours.
4. Change passwords for administrator and key user accounts if you suspect a compromise.
5. Take a backup (files + database) before making changes so you can revert if needed.

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Detection — what to look for (logs and WordPress queries)

You should look for signs of exploitation and suspicious requests. Note: these queries are safe; they are not exploit instructions.

• Web server / access logs (example greps):
  • Search for requests touching the plugin folder:
    • grep -i "eventlist" /var/log/apache2/access.log*
    • grep -i "eventlist" /var/log/nginx/access.log*
  • Search for POSTs to admin-ajax.php or admin-post.php around the time of suspicious activity:
    • grep "POST /wp-admin/admin-ajax.php" /var/log/nginx/access.log | grep -i "eventlist"
• WordPress database checks:
  • Check for new users added recently (customize date range as required):

    SELECT ID, user_login, user_email, user_registered FROM wp_users WHERE user_registered >= '2025-08-01' ORDER BY user_registered DESC;

  • Check for new administrator accounts:

    SELECT u.ID, u.user_login, m.meta_value FROM wp_users u JOIN wp_usermeta m ON u.ID = m.user_id AND m.meta_key = 'wp_capabilities' WHERE m.meta_value LIKE '%administrator%';

  • Verify suspicious users’ capabilities and last_login timestamps (if you have a last_login plugin or site logs).
• WordPress and plugin logs:
  • If the site uses an activity log plugin, search for role changes, password resets, plugin settings changes, or new admin creation.
• File system and integrity:
  • Search for recently modified files in wp-content/uploads, wp-content/plugins, and wp-content/themes:

    find /path/to/site -type f -mtime -7 -ls

If you see unexplained administrator creation, suspicious file changes, or POSTs to plugin endpoints from low-level accounts, assume compromise and proceed with the incident response steps below.

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WAF and virtual-patching guidance (recommended if you cannot update immediately)

If you run a WAF (network or host-based), you should deploy a virtual patch to block likely exploitation patterns. Virtual patching reduces exposure by stopping exploit attempts before they trigger the vulnerable plugin code.

Recommended WAF actions (templates / high-level guidance):

• Block requests that attempt to invoke plugin-specific AJAX or endpoints when the caller is an authenticated user with limited privileges.
• Deny POST requests containing parameters that are unique to the plugin’s admin operations (monitor logs for the plugin’s parameter names before creating rules).
• Rate-limit POST requests to admin-ajax.php from individual accounts / IPs to slow brute-force or automated exploitation attempts.
• Create rules to block (or challenge with CAPTCHA) suspicious requests where:
  • The request targets /wp-admin/admin-ajax.php or /wp-admin/admin-post.php and
  • The request contains parameters referencing the plugin (for example, a parameter including the string eventlist or plugin-specific action names) and
  • The request comes from an authenticated user account or has an authenticated cookie but no admin capability.

A generic ModSecurity rule example (template only; do not copy verbatim without testing):

# Block suspicious admin-ajax requests referencing eventlist plugin (template)
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" 
  "chain,phase:2,deny,status:403,msg:'Blocked possible Event List exploit attempt'"
  SecRule ARGS_NAMES|ARGS_VALUES "@rx (?i:eventlist|event-list|el_)" "t:none,ctl:auditLogParts=+E,log"

Note: Test any rule in blocking mode with logging first (audit), then move to deny when comfortable.

If your WAF supports role-aware logic via integration with WordPress (less common), block plugin administrative endpoints for users without required capabilities.

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Safe temporary hardening on WordPress (if you cannot deactivate/update)

1. Disable public registration temporarily:
   • Settings → General → uncheck “Anyone can register” to stop new Subscriber accounts during the window of heightened risk.
2. Reduce default user registration role:
   • If you must keep registrations enabled, set the default role to a minimal custom role or disable capabilities for the Subscriber role temporarily.
3. Limit access to plugin management pages:
   • If you know the admin page slug the plugin uses (e.g., /wp-admin/admin.php?page=…), restrict access by role through a small snippet in a site-specific plugin or child theme functions.php. Example (conceptual; modify carefully):

add_action('admin_init', function() {
    if ( ! current_user_can('manage_options') ) {
        // If current admin page belongs to Event List plugin, block access
        $page = isset($_GET['page']) ? sanitize_text_field($_GET['page']) : '';
        if ( stripos($page, 'eventlist') !== false || stripos($page, 'event-list') !== false ) {
            wp_die('Access denied.');
        }
    }
});

Warning: Do not deploy code without testing on a staging site first. If your plugin uses unknown slugs or AJAX actions, the safest option is to deactivate it entirely until you can apply the official fix.

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Incident response (if you detect signs of compromise)

If you have evidence (or strong suspicion) that an attacker exploited this vulnerability, take the following steps immediately:

1. Isolate and contain:
   • Temporarily disable plugin and any suspicious user accounts.
   • Consider putting site into maintenance mode or temporarily blocking public access while you investigate.
2. Preserve logs and backups:
   • Export webserver logs, WordPress activity logs, and a full backup of the site (files + DB) for forensic analysis.
3. Rotate secrets:
   • Change all administrator passwords, and consider rotating API keys, SSH keys, and any other secrets stored on the site or used by WordPress.
4. Search for persistence:
   • Scan wp-content/uploads and plugin/theme directories for PHP files that shouldn’t be there.
   • Look for scheduled tasks (wp_cron) that execute unknown code.
   • Search database for unexpected admin accounts or changed options.
5. Clean or restore:
   • If you find evidence of backdoors or persistent malicious files, consider restoring from a known clean backup from before the compromise.
   • If you cannot confidently clean and verify the site, use professional incident response.
6. Harden and monitor:
   • After cleanup and patching, tighten monitoring and enable strong logging. Set alerts for new admin creation, role changes, file modifications, and high-risk plugin activations.
7. Notify stakeholders:
   • Notify your hosting provider if you need help with logs or server-level scans.
   • If site handles sensitive data (users, payments), follow applicable notification laws/regulations.

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Practical checklist — what you should do now (step-by-step)

1. Update Event List plugin to 2.0.5 or later (best) across all sites.
2. If update is not immediately possible: deactivate the plugin.
3. Disable public registration or restrict default role.
4. Audit users for new or changed admin accounts.
5. Rotate admin passwords and apply MFA to all admin users.
6. Scan site for malware and backdoors (file scans and DB checks).
7. Preserve logs and backups if suspect compromise.
8. Implement temporary WAF rules or enable virtual patching.
9. Monitor logs and set alerts for suspicious activity.
10. Document actions taken and the timeline for operational and compliance records.

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Hunting queries and indicators of compromise (IOCs)

Useful grep and SQL examples that will help you hunt for suspicious activity.

• Search webserver logs for plugin paths:

  grep -i "wp-content/plugins/eventlist" /var/log/nginx/access.log* /var/log/apache2/access.log*

• Search for suspicious POSTs to admin-ajax:

  grep "POST /wp-admin/admin-ajax.php" /var/log/nginx/access.log* | grep -i "eventlist"

• Query WordPress for recent administrator creations:

  SELECT u.user_login, u.user_email, u.user_registered, um.meta_value
  FROM wp_users u
  JOIN wp_usermeta um ON u.ID = um.user_id AND um.meta_key = 'wp_capabilities'
  WHERE um.meta_value LIKE '%administrator%'
  ORDER BY u.user_registered DESC;

• Find recently modified PHP files:

  find /path/to/wordpress -name "*.php" -mtime -14 -ls

Set up alerts based on these searches using your monitoring or SIEM system.

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Recovery and long-term hardening

• Keep plugins and WordPress core updated, and enable auto-updates for plugins that are critical and well-maintained.
• Apply the principle of least privilege: remove unnecessary administrator accounts and ensure users have only the capabilities they need.
• Use multi-factor authentication for admin-level accounts.
• Enable file integrity monitoring to alert on new or modified PHP files in upload directories.
• Regularly audit installed plugins — remove plugins that are unused or unmaintained.
• Establish a backup and disaster recovery strategy with immutable backups retained offsite.
• Regularly review and test your incident response plan.

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Why an attacker loves privilege escalation vulnerabilities

Privilege escalation is one of the most dangerous types of vulnerabilities because it turns a minor foothold into full control. Many sites allow low-level registration or rely on third-party forms and comments; once an attacker has a Subscriber account, a flaw like CVE-2025-6366 lets them jump to administrator privileges. This makes exploitation both easy and highly rewarding for attackers, which is why these vulnerabilities are often rapidly weaponized after public disclosure.

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How to explain the situation to non-technical stakeholders

If you need to brief management, clients, or customers, use this short summary:

• What happened: A plugin used on our site had a vulnerability that could allow a low-level user to become an administrator.
• What we did: We updated the plugin (or disabled it), scanned the site, changed admin passwords, and are monitoring for suspicious activity.
• What this means: If an attacker exploited the site before our remediation, they could have installed malicious code or created admin accounts. We have measures in place to detect and clean any compromise.
• Next steps: Continue monitoring, harden the site, and review logs/backups to ensure the site is clean.

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Frequently asked questions (FAQ)

Q: Can I safely apply the update right away?

A: Yes — updating to 2.0.5 (or later) is the recommended action and should resolve the vulnerability. Always take a backup first and test updates on staging when possible.

Q: I can’t update now — can I patch in place?

A: The safest temporary option is to deactivate the plugin. If deactivation is not possible, apply WAF virtual patching and restrict registrations and admin access until you can update.

Q: What if my site is already compromised?

A: Follow the incident response steps above — preserve logs, isolate the site, rotate credentials, scan for persistence, and consider restoring from a known clean backup.

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A practical (non-exploit) example: using logs and user checks to confirm whether you were targeted

1. Run the grep queries above to find requests referencing the plugin.
2. Confirm whether there are POSTs to admin-ajax.php or plugin endpoints from logged-in users whose cookie indicates Subscriber accounts (match IP/user-agent and timestamps).
3. In WordPress, check for new admin users and changes to wp_usermeta capabilities.
4. If you see suspicious evidence, assume the worst and escalate to the incident response workflow.

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Monitoring and alerts to set up immediately

• Alert on creation of users with administrator capability.
• Alert on changes to wp_options that affect site URLs or core settings.
• Alert on PHP files added or modified under wp-content/uploads.
• Alert on POSTs to admin-ajax.php with high frequency from the same IP or user in a short time window.
• Set up outbound traffic monitoring — unusual outbound connections from the host may indicate exfiltration.

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New: Why free managed firewall protection helps (short title to get you started)

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Final thoughts (expert opinion)

Privilege escalation vulnerabilities involving plugins are among the most critical issues a WordPress site can face because they turn a low-risk vector (a Subscriber account) into a full site takeover. The only reliable long-term fix is to update the vulnerable plugin to the patched version (2.0.5+). In the short-term, combine plugin updates with WAF virtual patching, registration restrictions, credential rotation, and forensic checks. If you run multiple sites or manage clients, treat this vulnerability with urgency: apply updates and mitigations site-by-site and automate updates where safe.

If you’d like hands-on guidance for triage on a specific site, or help deploying virtual patches across a fleet of sites, the WP-Firewall team is available to assist.

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Appendix — Useful commands and snippets

• Grep for plugin references in logs:

  grep -i "eventlist" /var/log/nginx/access.log* /var/log/apache2/access.log*

• Find recently modified PHP files:

  find /path/to/wordpress -name "*.php" -mtime -14 -ls

• SQL: find admins added recently:

  SELECT u.user_login, u.user_email, u.user_registered
  FROM wp_users u
  JOIN wp_usermeta um ON u.ID = um.user_id
  WHERE um.meta_key = 'wp_capabilities' AND um.meta_value LIKE '%administrator%'
  ORDER BY u.user_registered DESC;
      

• Conceptual PHP snippet to temporarily block plugin admin pages (test in staging first):

  add_action('admin_init', function() {
      if ( ! current_user_can('manage_options') ) {
          $page = isset($_GET['page']) ? sanitize_text_field($_GET['page']) : '';
          if ( stripos($page, 'eventlist') !== false || stripos($page, 'event-list') !== false ) {
              wp_die('Access to this admin page is currently disabled for security reasons.');
          }
      }
  });
      

If you manage WordPress sites, make updating, monitoring, and response part of your routine. Vulnerabilities like CVE-2025-6366 are reminders that layered defenses — prompt patching, least privilege, MFA, WAF protections, and backups — are essential for minimizing risk.

If you’d like help rolling out these mitigations across multiple sites, or a review of your current protections, our WP-Firewall team can assist.