Urgent: BizCalendar Web (≤ 1.1.0.50) — Authenticated Contributor Local File Inclusion (CVE-2025-7650) and What Site Owners Must Do Now

Author: Hong Kong Security Expert  |  Date: 2025-08-15

Summary

• Vulnerability: Local File Inclusion (LFI)
• Affected plugin: bizcalendar-web
• Vulnerable versions: ≤ 1.1.0.50
• Privilege required: authenticated user with Contributor role or higher
• CVE: CVE-2025-7650
• Reported: 14 August 2025
• Official fix: Not available at time of reporting

As a security practitioner based in Hong Kong, I advise rapid, practical steps for site owners and administrators. This LFI allows an authenticated Contributor (or higher) to read local files when exploited. Although authentication reduces immediate exposure compared with unauthenticated flaws, Contributor accounts are commonly present on multi-author sites and editorial platforms — treat this as actionable and urgent.

What is Local File Inclusion (LFI) and why it matters

Local File Inclusion (LFI) occurs when an application accepts a file path and includes or reads that file without proper validation. An attacker who controls that path can read sensitive files (for example wp-config.php), logs, or other local artifacts. In some environments LFI can be chained into code execution.

Key impacts:

• Disclosure of secrets (database credentials, salts, API keys)
• Exposure of user data and configuration files
• Potential pivot to further attacks if other misconfigurations exist
• Site compromise and data theft

The mechanics of this vulnerability (high-level)

• The plugin accepts file path input via parameters or internal include logic.
• Input is not sufficiently sanitized or normalised; directory traversal or direct local path selection is possible.
• An authenticated user with Contributor-level privileges can supply crafted input to include arbitrary files from the server.
• The included file content may be returned to the requester or otherwise exposed.

Proof-of-concept details are intentionally excluded here. Site owners and security staff should assume the classification is actionable and proceed to mitigation.

Who is at risk?

• Sites running bizcalendar-web ≤ 1.1.0.50.
• Sites that allow Contributor or higher-level registrations without strict vetting.
• Multi-author blogs and editorial platforms with external contributors.
• Sites that have not hardened file permissions or rotated secrets recently.

If you run the plugin, assume risk until you complete corrective steps. Even if you believe there are no Contributors, verify roles and account privileges.

Immediate actions (0–48 hours)

If you manage a WordPress site, perform the following without delay.

1. Inventory and confirm
   • Check whether your site uses bizcalendar-web and confirm the plugin version in WP Admin > Plugins or via SFTP/SSH at wp-content/plugins/bizcalendar-web/.
2. If you run a vulnerable version
   • Deactivate the plugin immediately if you can tolerate the functionality loss.
   • If the plugin is essential and cannot be deactivated, apply compensating controls immediately: enable virtual patching via your Web Application Firewall (WAF), restrict access to plugin endpoints by IP, or place the site behind an access control proxy while you plan a safer remediation.
3. Rotate secrets
   • Rotate database credentials (change the DB user password and update wp-config.php).
   • Rotate any third-party API keys saved in the plugin or the site.
   • Generate new WordPress salts (AUTH_KEY, SECURE_AUTH_KEY, etc.) in wp-config.php.
4. Limit and audit user access
   • Revoke Contributor or higher privileges for any untrusted users.
   • Temporarily remove or downgrade Contributors until the issue is resolved.
   • Enforce strong passwords and enable multi-factor authentication for admin and editor accounts where possible.
5. File permissions & server hardening
   • Ensure wp-config.php cannot be directly served by the webserver (deny access in server config if necessary).
   • Use least-privilege filesystem permissions: WordPress files should be owned by the webserver user with minimal write rights.
   • Disable directory listing on the webserver.
6. Backup and snapshot
   • Take a full site backup (files + database) and store it offline.
   • If cloud-hosted, snapshot the server for potential forensics.
7. Monitor logs
   • Monitor webserver, PHP, and application logs for suspicious activity targeting plugin endpoints.

Indicators of Compromise (what to look for)

Inspect logs, databases and the filesystem for these signs:

• Requests targeting plugin endpoints or PHP files under wp-content/plugins/bizcalendar-web/.
• Requests containing traversal patterns (../) or attempts to access wp-config.php, .env, or /etc/ files.
• Unusual volume of GET/POST requests from authenticated accounts (Contributor or higher).
• Pages exposing file content or configuration lines unexpectedly.
• New or modified administrator accounts, unexpected user role changes, or unexpected plugin updates.
• New scheduled tasks in wp_options or unexpected files in wp-content/uploads/.

If you observe suspicious activity, preserve logs and consider taking the site offline for investigation.

Longer-term mitigation and hardening (checklist)

• Remove or replace unmaintained plugins. If no vendor response or fix, remove the plugin or migrate to an actively maintained alternative.
• Enforce least privilege: audit roles and capabilities; reduce number of Contributor+ accounts.
• Disable file editing in WordPress: set define(‘DISALLOW_FILE_EDIT’, true) in wp-config.php.
• Use SSH/SFTP keys for administrative access and restrict direct access where possible.
• Avoid reusing the same database credentials across multiple sites; segment hosting and databases.
• Keep off-site, immutable backups with versioning.
• Apply defense-in-depth: filesystem restrictions, webserver hardening, WAF protections, strict security headers, and continuous monitoring.
• Maintain an inventory of plugins and themes and track maintenance status and versions.

How a WAF helps (general guidance)

A properly configured Web Application Firewall (WAF) provides virtual patching and blocks exploit attempts before they reach vulnerable code. Use WAF controls as an interim barrier while you pursue other remediations.

Key WAF controls to configure:

• Apply rules to detect and block path traversal patterns and LFI indicators.
• Block requests containing strings like “../”, encoded traversal sequences, “wp-config.php”, or “.env” in parameters or bodies.
• Restrict plugin-specific endpoints to expected HTTP methods and required authentication tokens.
• Rate-limit authenticated requests to sensitive plugin endpoints to reduce brute-force or automated abuse.
• Enforce CSRF token checks and referer-origin validation where feasible.
• Enable robust logging and alerting so you can respond to blocked attempts quickly.
• Test rules in staging or monitoring mode first to avoid blocking legitimate workflows.

Suggested WAF rule patterns (conceptual — test before production)

• Block if query string or POST body contains “../” or encoded equivalents.
• Block requests that include “wp-config.php”, “.env”, or “/etc/passwd” in parameters or body.
• Whitelist only known actions and parameters for bizcalendar-web endpoints; drop unknown or unexpected parameter names.
• Drop requests that pass file path parameters (filename, template, include, view, path) unless matched against a strict allowlist.
• Rate-limit authenticated users accessing the plugin endpoints (e.g., limit N requests per minute per user).
• Require valid CSRF tokens and origin checks for sensitive actions.

These are conceptual examples. Implement and test rules carefully to avoid breaking legitimate site functionality.

How hosting providers or managed security teams can assist

If you use a managed host or a security provider, ask them to:

• Apply temporary virtual patching at the edge or reverse proxy level.
• Perform log analysis and intrusion detection to check for past exploitation attempts.
• Help snapshot and preserve evidence for forensic review.
• Advise on safe rollback or restore procedures from clean backups.

How to safely test whether your site is protected

1. Clone your site to a staging environment (files + database snapshot).
2. Apply WAF rules on staging and run simulated traversal traffic to ensure blocking and acceptable false-positive rates.
3. Validate contributor workflows to ensure normal operations are not impeded.
4. After validation, roll protections to production during a maintenance window.

If no staging environment is available, enable WAF in monitoring mode first and observe blocked attempts before switching to blocking mode.

If you suspect compromise — incident response playbook

1. Isolate: Put the site in maintenance mode or take it offline to stop further data exfiltration. Disable the vulnerable plugin immediately.
2. Preserve evidence: Preserve logs (webserver, WAF, database, FTP/SFTP). Make a full copy of the site and database for forensic analysis.
3. Rotate secrets: Reset DB passwords, API keys, WordPress salts, and force password resets for users. Consider invalidating sessions.
4. Scan for indicators: Search for webshells, modified PHP files, new scheduled tasks or suspicious files in uploads and plugin folders.
5. Clean and restore: If you can confidently remove malicious code, clean the site and monitor closely. If unsure, restore from a known clean backup taken before the compromise.
6. Post-incident: Report to your hosting provider and stakeholders. Improve logging, monitoring, and patching cadence.

For complex compromises, engage a professional incident response team experienced in WordPress forensic analysis.

Communicating to your team and contributors

• Notify stakeholders of the vulnerability and temporary measures (plugin deactivation, forced password resets).
• Ask contributors to change passwords and follow secure submission guidelines.
• Enforce invitation/approval workflows for external contributors and review role assignments.

Why act quickly

LFI bugs are attractive because they are simple to exploit and can expose high-value targets such as configuration files. Even when authentication is required, automated credential stuffing and account enumeration campaigns can turn low-privilege accounts into an entry point. Fast remediation reduces the window of opportunity for attackers.

Recommended routine after mitigation

• Reinstall or update the plugin only after the vendor releases an official fix. If no fix is forthcoming, replace the plugin with a secure, actively maintained alternative.
• Maintain a regular patch cycle for all plugins, themes, and WordPress core.
• Schedule incident response drills and run regular vulnerability scans.
• Keep an up-to-date inventory of third-party plugins and their maintenance status.

Final thoughts

This LFI disclosure is a strong reminder that plugin security is among the highest operational risks for WordPress sites. The timeline from disclosure to exploitation can be short. If your site uses bizcalendar-web, follow the immediate steps: deactivate the plugin if possible, rotate secrets, restrict Contributor roles, and apply compensating controls such as WAF virtual patches or access restrictions until a vendor fix is available.

Stay vigilant and reduce your site’s attack surface: accurate inventories, least-privilege access, and rapid response plans are your best defence.

— Hong Kong Security Expert

Further reading and resources

• WordPress hardening guide (official)
• OWASP Top 10
• Backup and incident response best practices (vendor-neutral guides)