Local File Inclusion in MAS Videos (≤ 1.3.2): What WordPress Site Owners Must Do Right Now

Author: Hong Kong security expert — concise, practical guidance for site owners and administrators in Hong Kong and the region.

Summary

A Local File Inclusion (LFI) vulnerability (CVE-2025-62753) affecting the WordPress plugin “MAS Videos” (versions ≤ 1.3.2) was publicly reported on 30 Dec, 2025. The issue allows an attacker with limited privileges to force the plugin to include local files from the site filesystem and render their output. Depending on environment and configuration, LFI can reveal sensitive files (for example, wp-config.php), leak credentials, disclose critical information, and—when chained with other weaknesses—lead to full site compromise.

This advisory explains how the LFI works in this case, the realistic risk for WordPress sites, immediate actions, detection tips, containment and remediation steps, developer guidance for permanent fixes, and layered mitigations using hardening techniques and perimeter controls.

Why this vulnerability matters

Local File Inclusion vulnerabilities occur when an application accepts user-supplied input that determines a file to include or require, and fails to validate or constrain that input. Attackers exploit LFI by manipulating the input to reference files outside the intended directory (directory traversal), typically using sequences like ../ to walk up the directory tree. Successful LFI can expose sensitive data (database credentials, API keys, configuration) or be used in chained attacks to achieve code execution.

In the reported MAS Videos issue:

• A plugin endpoint accepts input that is used to include local files.
• Insufficient input sanitization and absence of a whitelist allowed path traversal and inclusion.
• The required privilege to trigger the vulnerable functionality is low (contributor-level capability), increasing real-world exposure on sites that permit low-trust users.
• The vulnerability is classified as LFI and carries a high confidentiality and integrity impact when chained with other flaws (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H as reported).

Because WordPress installations commonly store everything needed for takeover (DB credentials, salts, config values), even LFI that only exposes file contents can be devastating when combined with other weaknesses.

Realistic threat model for WordPress sites

Not every LFI is equally dangerous. Impact depends on environment and site configuration:

• Attack surface: If the vulnerable code is reachable without authentication, exploitation risk is very high. If a low-privileged authenticated user can reach it and your site allows registrations or editorial access by untrusted users, the risk is elevated.
• File visibility: Many WordPress setups store wp-config.php in the site root and keep uploads readable by the webserver. Predictable paths increase the chance of sensitive disclosure.
• PHP configuration: Settings such as allow_url_include (usually off) affect remote inclusion risk; for LFI, remote code execution is often achieved by including files an attacker can control (logs, uploaded files, temp files).
• Access to logs/uploads: If attackers can upload files or inject into logs, they may include these local files to execute PHP code.
• Defence-in-depth: Perimeter controls, file permission hardening and monitoring can reduce exploitation success even when a plugin is vulnerable.

Treat the reported vulnerability seriously: it is exploitable under realistic site conditions and administrators must act promptly.

Immediate actions (first 24 hours)

If you use the MAS Videos plugin (version ≤ 1.3.2) on any WordPress site, perform these immediate steps:

1. Identify affected installs
   • From WordPress admin: Plugins → Installed Plugins and check the MAS Videos version.
   • Or use WP-CLI:

     wp plugin list --status=active --format=json | jq '.[] | select(.name=="masvideos" or .name=="MAS Videos")'

   • Search hosting control panels and backups if you manage multiple sites.
2. Take the site to a safe state
   • If you cannot apply an update (no fixed version available), deactivate the plugin immediately:

     wp plugin deactivate masvideos

   • If you prefer not to deactivate, restrict public access to the plugin’s vulnerable endpoint (temporary). Deactivation is safest.
3. Isolate and snapshot
   • Make a full backup (files + database) and copy it offline for forensic analysis.
   • Capture server logs (webserver access/error logs), PHP-FPM logs and any edge logs you can access.
4. Rotate credentials
   • If you suspect access through this vulnerability, rotate database credentials and WordPress salts (in wp-config.php), and reset all administrator/editor passwords.
   • Revoke secrets used by integrations (API keys, third-party services) when in doubt.
5. Monitor and search for indicators of compromise (see Detection section).
6. Apply temporary network blocking
   • If you can, add server-level rules (IP blocks, maintenance mode) to limit exposure while you prepare remediation.

Detection: signals that someone may have tried to exploit LFI

Look for these indicators in logs and on disk:

• Webserver access logs containing traversal payloads: sequences like ../../, ..\ (Windows), %2e%2e%2f, %2e%2e%5c in query strings or POST bodies.
• Requests for well-known sensitive files such as /wp-config.php, /etc/passwd, /proc/self/environ.
• Responses containing sensitive content — search for “DB_USER”, “DB_PASSWORD”, “AUTH_KEY” or other wp-config patterns.
• Unexpected files in wp-content/uploads, tmp directories or other writable locations (webshells).
• File changes: modified plugin files, unexpected PHP files in uploads, timestamp anomalies.
• Unexpected user registrations or role escalations (the vulnerability requires low privilege; attackers may use contributor accounts).
• Suspicious outbound connections from the server (if remote code execution followed LFI).

If you observe these, treat the site as potentially compromised and follow incident response steps below.

Containment and incident response if you suspect compromise

1. Put the site into maintenance/offline mode or block inbound traffic until contained.
2. Preserve logs and evidence. Copy logs to a secure analysis host; do not overwrite.
3. Isolate compromised accounts: force password resets for all users and invalidate sessions.
4. Revoke credentials that may be leaked: rotate DB credentials, API keys, OAuth tokens, SFTP/SSH keys.
5. Scan for malware and webshells: use server-side scanners and manual inspection of suspicious files and directories.
6. Consider a full restore from a known clean backup (pre-incident) if you cannot confidently remove all traces.
7. Notify external services whose credentials were stored on the site and rotate keys as needed.
8. Perform a thorough post-mortem and harden the site before returning to normal operation.

If you are not confident performing these steps, engage a trusted security professional to assist. This is not the time to delay.

Short-term mitigations when no vendor fix is available

• Deactivate and remove the plugin from production sites immediately where possible.
• If deactivation is not feasible:
  • Restrict access to the specific plugin endpoint via .htaccess/nginx rules or server-level IP restrictions.
  • Remove or replace any plugin files that process external input (use safe placeholders).
• Apply server hardening:
  • Set restrictive file permissions (files 644, directories 755) and ensure wp-config.php is not world-readable (600 where possible).
  • Ensure the webserver user has minimal read/write access only to needed paths.
  • Enable open_basedir to limit PHP access to the WordPress directory.
  • Confirm allow_url_include is Off.
• Add an application-level whitelist if possible: restrict accepted include values to a server-side mapping.
• Temporarily disable contributor uploads or restrict file types and scan all uploads.
• Deploy edge rules (at CDN or server level) to detect and block traversal patterns.

How a WAF or edge filter helps — what to configure

A perimeter filter or WAF is a quick way to block active exploitation attempts without changing code. Useful controls include:

• Pattern-based rules to catch directory traversal sequences: block ../, ..%2f, %2e%2e%2f and equivalents.
• Block attempts to access sensitive paths: wp-config.php, wp-content/debug.log, /etc/passwd, /proc/self/environ.
• Sanitize and block suspicious POST/GET parameter patterns containing traversal characters.
• Rate-limit and automatically block IPs with repeated suspicious requests.
• Virtual patching: create a targeted rule for the vulnerable plugin’s endpoint and parameter names to prevent the specific inclusion vector.

Developer guidance: how to permanently fix LFI in plugin code

If you maintain the plugin or custom code, follow these secure coding practices to prevent LFI:

1. Never include files based on direct user input. Avoid constructs like include($_GET[‘file’]) or include($user_input . ‘.php’).
2. Implement a strict server-side whitelist: map allowed user-facing options to internal file paths. Example safe approach:

   <?php
   // Example: safe include using whitelist mapping
   $views = [
       'list'   => __DIR__ . '/views/list.php',
       'single' => __DIR__ . '/views/single.php',
   ];
   
   $requested = isset($_GET['view']) ? $_GET['view'] : 'list';
   
   if (!array_key_exists($requested, $views)) {
       // Invalid request - show default or error
       $requested = 'list';
   }
   
   // Use include on the resolved, safe path from the whitelist
   include $views[$requested];
   ?>

3. Validate and sanitize all input: use strict pattern matching and reject input containing dots, slashes or null bytes when a filename or key is expected.
4. Use realpath and base directory checks: resolve the real path and verify it begins with the allowed directory prefix. Example:

   <?php
   $base = realpath(__DIR__ . '/views');
   $path = realpath($base . '/' . $requested . '.php');
   
   if ($path === false || strpos($path, $base) !== 0) {
       // Invalid path - abort
       http_response_code(400);
       exit('Invalid request');
   }
   include $path;
   ?>

5. Principle of least privilege: only expose functionality to roles that absolutely need it; enforce capability checks server-side.
6. Avoid storing executable code in writable directories: do not include files from uploads/ or temp directories.
7. Logging and monitoring: log invalid include attempts and alert administrators.
8. Code reviews and static analysis: run static security scanners and CI checks for insecure patterns.

Hardening recommendations beyond the edge filter

• Disable file editing: add define('DISALLOW_FILE_EDIT', true); to wp-config.php.
• Keep WordPress core, themes and plugins updated; delete unused plugins/themes.
• Review and limit user roles; remove or downgrade unnecessary accounts.
• Enforce strong passwords and two-factor authentication for privileged accounts.
• Harden PHP settings:
  • disable_functions for exec, shell_exec, system if not required.
  • enable open_basedir to restrict filesystem access for PHP.
• Use secure file permissions and ownership on the server.
• Isolate sites (one site per account/container) to limit cross-site compromise.
• Schedule regular backups and verify restore procedures.

Practical sysadmin commands and checks

Useful commands to audit indicators or perform containment (run on the host via SSH):

# Find plugin version
grep -R "Version:" wp-content/plugins/masvideos -n

# Deactivate plugin using WP-CLI
wp plugin deactivate masvideos

# Search for traversal payloads in access logs
zgrep -E "%2e%2e|\\.\\.|%2f|%5c" /var/log/nginx/access.log*

# Search for wp-config disclosure in backups/logs
grep -R "DB_NAME\|DB_USER" /path/to/backups -n

# Detect recently modified PHP files (last 7 days)
find /var/www/html -name "*.php" -mtime -7 -ls

# Search for suspicious PHP files in uploads
find wp-content/uploads -type f -iname "*.php"

Copy logs off the host to a safe analysis machine before clearing or rotating anything.

If a compromise occurred: recovery checklist

1. Contain and isolate the affected host.
2. Identify the root cause (which plugin, version, vector).
3. Rebuild from a clean source: restore files from a known-good backup or reinstall WordPress core and plugins from trusted packages.
4. Rotate all secrets and credentials (DB users, API keys, salts).
5. Reinstall plugins from official repositories after confirming fixed versions are available.
6. Re-scan and monitor the site for residual backdoors or scheduled tasks (cron jobs).
7. Consider an external post-incident review to confirm all traces are removed.

Why prevention beats infection

An exploited LFI is often the first step in a multi-stage attack. Attackers can use LFI to:

• Read configuration files to obtain DB credentials.
• Include server logs or uploaded files to gain code execution.
• Deploy webshells and maintain persistence.
• Pivot to other accounts or services.

Blocking the vulnerability at the application perimeter, reducing privileged accounts and enforcing strict coding standards greatly reduce the likelihood of expensive and reputation-damaging incidents.

Practical timeline and expectations

• Immediate: Deactivate MAS Videos on production where possible. Back up and snapshot logs for analysis.
• Short term (24–72 hours): Apply network-level blocking, scan for indicators and rotate credentials if necessary.
• Medium term (days): Rebuild or restore from clean backup if compromised; implement code fixes or replace the plugin with a maintained alternative.
• Long term: Adopt continuous monitoring, staged testing for plugins, and regular vulnerability scanning.

Final checklist — what to do now

• Verify whether MAS Videos is installed and which version.
• If version ≤ 1.3.2, deactivate and remove the plugin until a fix is available.
• Make offline backups and preserve logs.
• Deploy edge rules to block LFI patterns and the plugin endpoint where possible.
• Scan the site for suspicious files and signs of compromise.
• Rotate DB and service credentials if you suspect exposure.
• Harden PHP settings and file permissions.
• If needed, engage a trusted security professional to triage affected sites and perform incident response.

Closing thoughts

Plugin vulnerabilities like CVE-2025-62753 highlight the importance of defence-in-depth. Even a single vulnerable plugin can lead to serious consequences if other controls are weak. Apply layered protections — perimeter filtering, strict server hardening, vigilant monitoring and a clear incident response plan — and treat low-privilege vulnerabilities as urgent. If you require bespoke guidance for your environment, consult a qualified security professional who can review your configuration and logs.