Plugin Name	Advanced File Manager
Type of Vulnerability	Arbitrary file deletion vulnerability
CVE Number	CVE-2025-0818
Urgency	High
CVE Publish Date	2025-08-12
Source URL	CVE-2025-0818

Advanced File Manager <= 5.3.6 — Arbitrary File Deletion (CVE-2025-0818): What Site Owners Must Do Now

Author: WP‑Firewall Security Team
Date: 2025-08-12
Tags: WordPress, security, WAF, vulnerability, incident response

Summary: A critical unauthenticated arbitrary file deletion vulnerability (CVE-2025-0818) affects Advanced File Manager versions up to 5.3.6. The vendor released version 5.4.0 to fix the issue. This vulnerability can be weaponized to delete core files, plugins, themes and user content — potentially causing site outages, data loss and follow-on compromise. In this post our WP‑Firewall research and incident response team explains the risk, detection, mitigation and long-term hardening steps you should take immediately.

Quick facts

• Vulnerability: Arbitrary File Deletion (unauthenticated)
• Affected software: Advanced File Manager (WordPress plugin) — versions <= 5.3.6
• Fixed in: 5.4.0
• CVE: CVE-2025-0818
• CVSS (reported): 6.5 (High)
• Privilege required: None (Unauthenticated)
• Published: 12 August 2025

---

Why this matters — plain language

If you run the Advanced File Manager plugin and it’s not updated to 5.4.0, an attacker can send web requests that cause the plugin to delete files on your server without authentication. Unlike an ordinary file-deletion operation that requires an admin login, this flaw lets anyone on the internet trigger file removal.

The consequences are immediate and tangible: a malicious actor could delete configuration files (for example wp-config.php), .htaccess files, theme or plugin files, uploads and backups. That can break your site, remove security controls, wipe media and leave you with a partially or completely unusable installation. In some environments file removal can be used as a stepping stone to further compromise.

Because this can be triggered without login and because exploit automation is common, this type of vulnerability is very likely to be scanned for and mass-exploited quickly. Treat it as an emergency if your site uses the affected plugin version.

---

How the vulnerability works (high level, non-exploitative)

We will not publish exploit code here, but it helps to understand the technical root cause so you can make the right mitigation decisions.

• The plugin exposes file manager functionality (based on a file management connector/library) to handle file operations such as list, create, upload, rename and delete.
• An insufficient authorization and/or input validation control exists on the endpoint that handles deletion requests. In particular, the endpoint validates user-supplied paths and parameters improperly (or not at all), allowing an attacker to craft a request that causes the server to delete files outside of intended boundaries.
• The vulnerability falls into the broader category of injection/directory traversal/validation failure: user input ultimately influences a filesystem call (e.g., unlink or equivalent) without safe canonicalization and root restriction checks.

Because the endpoint accepts unauthenticated requests and there is no gating on dangerous commands, the attacker does not need valid WordPress credentials; they only need to reach the vulnerable endpoint.

---

Real-world impact — what an attacker can do

An attacker with network access to your site can:

• Delete core WordPress files and break the site (e.g., wp-config.php, index.php, core plugin or theme files).
• Remove plugin or theme code to disturb or disable security controls and monitoring.
• Delete media uploads and backups stored in web-accessible directories.
• Remove .htaccess or web server configuration files to change site behavior.
• Combine deletion with other actions (e.g., replacing files, clearing logs) to hinder detection or cleanup.

Even if the attacker only deletes non-critical files, repeated or targeted deletions can erode data integrity and availability. In multi-tenant hosting environments or shared codebases, the impact can extend beyond a single site.

---

Immediate actions (for every site owner)

If you run WordPress and use Advanced File Manager, follow these steps in the exact order below.

1. Check the plugin version now
   • In your WordPress admin, go to Plugins and confirm the version of Advanced File Manager. If it shows <= 5.3.6, act immediately.
2. Update the plugin to 5.4.0 or later
   • Updating is the definitive fix. Apply the update from the official repository or the plugin vendor.
3. If you cannot update immediately, deactivate the plugin
   • Deactivation prevents the vulnerable endpoints from being available. If your site relies on the plugin for critical functionality, consider alternative safe workflows until you can update.
4. If deactivation is not possible, remove or block access to the plugin’s web endpoints
   • Rename or move the plugin directory via SFTP: wp-content/plugins/advanced-file-manager -> wp-content/plugins/advanced-file-manager.disabled
   • Or apply a webserver rule (see WAF / webserver mitigation suggestions below).
5. Restore missing/deleted files from backup if you already see data loss
   • Isolate and preserve forensic artifacts (logs, backups) before restoration. If you suspect compromise, follow the incident response steps below.
6. Monitor logs and alerts closely for suspicious traffic to any file-manager connector endpoints
   • Look for requests containing command-like parameters, high request rates or repeated failures from the same client IP.

If you maintain multiple WordPress sites, automate these checks across your fleet. Attackers scan large IP ranges and will attempt to find vulnerable sites quickly.

---

Detection: indicators of compromise (IoCs) and what to look for

Look for these signs in your access logs, application logs and hosting control panel:

• HTTP requests to plugin paths such as (examples): /wp-content/plugins/advanced-file-manager/ (or endpoints that look like file-manager connectors)
• Requests containing suspicious path parameters, directory traversal sequences (../ or %2e%2e%2f), or command-like parameters referring to delete/remove/unlink
• Sudden 200 responses for previously non-existent delete operations
• Missing files that were present moments before (e.g., wp-config.php, plugins, themes, uploads)
• Unexpected database changes when file deletion is paired with other operations
• Error messages from PHP complaining about file not found following an action
• Elevated traffic or scanning behavior from IPs that try the same endpoint across many sites

If you find direct evidence of file deletions, take a conservative approach: assume compromise and follow an incident response workflow.

---

WAF and webserver mitigation recommendations (virtual patching)

When an urgent vendor patch is available, update. When you cannot update immediately (time, staging, compatibility testing, complex environments), you can mitigate with WAF rules or webserver configuration changes. The following are defensive patterns we use to protect customers; they are intentionally generic and focused on blocking malicious requests while minimizing false positives.

Important: test any rule in staging or log-only mode first.

1. Block access to the plugin directory or connector endpoints
   • Use server rules to deny all public access to known plugin entry points for the file manager (unless required for trusted administrators).
   • For Apache: deny access to the plugin connector path with a RewriteRule/Require all denied.
   • For Nginx: return 403 for requests to the connector path.
2. Block unauthenticated commands
   • Block HTTP requests that contain suspicious parameters consistent with file management commands unless they originate from authenticated admin IPs.
3. Block directory traversal patterns
   • Drop requests containing ../ or percent-encoded equivalents (%2e%2e%2f, %2e%2e/). Apply with care — some applications legitimately supply encoded characters.
4. Rate-limit or fingerprint and block scanners
   • Aggressive scanning and repeated attempts to reach the same endpoint are strong signals. Rate-limit or block offending IPs temporarily.
5. Deny unusual user-agents and request patterns
   • Block or challenge known automated scanners or empty/garbage user-agents targeting file endpoints.
6. Enforce authentication for file ops
   • For internal connectors used by your workflow, restrict by IP or require authentication via Basic Auth or a reverse proxy in front of the endpoint.
7. Monitor and alert on blocked hits
   • Configure your WAF to alert when a mitigation rule triggers frequently — someone is probing your site.

Sample conceptual WAF rule logic (do not copy verbatim to production without testing):

• If request path contains “advanced-file-manager” AND HTTP method in (POST, DELETE) AND (query string contains “cmd=delete” OR body contains delete-like parameter) => block or challenge.
• If request contains “../” OR “%2e%2e” => block.

These rules are virtual patches — temporary shields until the plugin update is applied. They dramatically reduce risk when tuned properly.

---

Recommended server-side hardening steps (beyond patching)

1. File and directory permissions
   • Ensure files are not world-writable. Typical secure defaults: files 644, directories 755. The WordPress root should be owned by a restricted user; PHP processes should not run as the file owner when possible.
2. Disable PHP execution in upload directories
   • Prevent arbitrary PHP files from executing in wp-content/uploads by blocking execution with webserver rules (deny .php in the uploads folder).
3. Enforce least privilege for hosting users
   • Avoid shared accounts with write access to multiple sites.
4. Restrict direct access to plugin folders that don’t need public access
   • Use webserver controls to block listing and direct access where possible.
5. Keep regular, tested backups off-site
   • Store backups outside the document root and test restores periodically.
6. Enable logging and centralized log collection
   • Keep access and error logs for investigation; ship logs to a central system for long-term retention.
7. Use integrity monitoring
   • Tools that monitor file changes and alert on unexpected deletions/modifications greatly speed detection.

---

Incident response: step-by-step playbook

If you confirm exploitation or see signs of deletion:

1. Isolate and snapshot
   • Take a full backup (files + database) immediately to preserve a forensic snapshot. Do not rely on the compromised environment for evidence.
2. Put the site in maintenance mode or take it offline
   • Stop further damage and reduce exposure.
3. Identify scope
   • What files were deleted? Which endpoints were accessed? Determine the time window and likely attacker IPs.
4. Preserve logs and communicate with host
   • Host logs and server-level access logs often reveal attacker behavior. Notify your hosting provider — they may assist with deeper forensics.
5. Restore from a clean backup
   • Restore files and database from a backup taken before the incident. Verify clean state before bringing the site back online.
6. Rotate all credentials
   • Reset WordPress admin passwords, database passwords, FTP/SFTP keys, API tokens and any service credentials that may have been exposed.
7. Update everything
   • Update WordPress core, all plugins and themes (including the vulnerable file manager) to patched versions.
8. Re-scan and harden
   • Perform malware scanning and integrity checks. Apply the hardening measures described earlier and enable the WAF virtual patches.
9. Root-cause and lessons learned
   • Document the timeline and implement controls to prevent recurrence (developer fixes, staging tests, monitoring).

If you lack internal incident response experience, engage a professional security responder. Cleanup mistakes are common and can leave persistent backdoors if not handled correctly.

---

How developers should fix this class of issue

If you develop file-management code or plugins, this vulnerability is an important case study.

Key defensive coding practices:

• Enforce authorization for any destructive operation
  • Any delete operation must be authorization-gated. Use WordPress capability checks (e.g., current_user_can('delete_plugins') or a site-specific capability), nonces and strong server-side checks.
• Canonicalize and validate paths
  • Use realpath() or similar to resolve user-supplied paths and verify they are inside an allowed base directory. Reject paths that escape the base (../).
• Avoid dangerous direct filesystem calls with untrusted input
  • Never call unlink or rmdir on user-controlled input without strict validation.
• Explicit allow-lists, not deny-lists
  • Accept only known-good file locations and patterns, rather than attempting to block everything suspicious.
• Principle of least privilege
  • Minimize the filesystem area the plugin can modify. Prefer interactions through WordPress APIs (where possible) that apply permission checks.
• Unit tests and fuzzing
  • Test boundary conditions like path traversal, long file names, encoded sequences and symlinked directories.
• Security review and third-party libraries
  • If relying on a file-manager library, track its advisories and keep it up to date. Libraries change; maintainers should get notified of security fixes.

These steps dramatically reduce the chance of similar vulnerabilities being introduced.

---

Why automated exploitation is likely and what to expect next

Vulnerabilities that allow unauthenticated file system damage are attractive to attackers because:

• They are low-effort: no credentials needed.
• They are high-impact: the attacker can destroy evidence, disable security, or remove backups.
• They are easy to automate and scan for across the web.

Expect scanning and exploitation attempts within hours of public disclosure. Attackers use low-cost cloud hosts and botnets to probe large numbers of sites. That’s why rapid detection and virtual patching are vital.

---

Long-term risk management for agencies and hosts

If you manage multiple sites or host WordPress at scale, a single plugin vulnerability becomes an operational problem. Invest in:

• Automated inventory and vulnerability scanning for installed plugins across your fleet.
• A policy for emergency plugin updates (testing + rollout).
• Virtual patching capability (WAF rules that can be applied centrally).
• Clear incident response procedures and communication templates.
• Regular backups and validated restores as part of your SLA.

Taking these steps reduces the time between vulnerability discovery and full remediation across thousands of sites.

---

Preventive checklist — what to do in the next 24/72 hours

Within 24 hours:

• Verify if the plugin is installed and if so check version.
• If version <=5.3.6, update to 5.4.0 immediately.
• If immediate update is not possible, deactivate or block the plugin directory.

Within 72 hours:

• Review server logs for suspicious requests to file-manager endpoints.
• Apply temporary WAF/webserver rules to block malicious patterns.
• Ensure you have a tested, recent off-site backup.
• Rotate administrative credentials.

Within 2 weeks:

• Audit other plugins for similar exposure.
• Implement file integrity monitoring and alerting.
• Review deployment and patching procedures to reduce time-to-patch.

---

What WP‑Firewall recommends

As a WordPress security provider we recommend the following immediate layered approach:

1. Apply the vendor patch (update the plugin to 5.4.0 or later).
2. Activate virtual patching in front of your site to block probing and command-like requests if you cannot patch immediately.
3. Harden file permissions, disable PHP execution in uploads, keep backups off-site and test restores.
4. Monitor access logs for IoCs and set up alerts for deletion-like activity.
5. If deletion is suspected, isolate the site, preserve evidence and follow a conservative restore and rotation process.

If you prefer us to protect your site while you handle updates and cleanup, we offer managed protection options and automated virtual patching that can stop exploit attempts at the perimeter.

---

Protect Your Site Now — Start with WP‑Firewall Free Plan

Title: Start Protecting Your WordPress Site with WP‑Firewall Free Plan

Get immediate, managed protection for your WordPress site with our free Basic plan. It includes a managed firewall, unlimited bandwidth, a Web Application Firewall (WAF), malware scanning and mitigation against OWASP Top 10 risks — precisely the layers that block and detect attacks like CVE‑2025‑0818 before they reach WordPress. If you manage multiple sites or need faster incident response, our paid plans add automatic malware removal, IP blacklisting/whitelisting and advanced virtual patching features.

Sign up for the WP‑Firewall Basic (Free) plan today and reduce your exposure while you patch:
https://my.wp-firewall.com/buy/wp-firewall-free-plan/

Features at a glance:

• Basic (Free): Managed firewall, WAF, malware scanner, OWASP Top 10 protections, unlimited bandwidth.
• Standard: Everything in Basic + automatic malware removal and basic IP allow/block controls.
• Pro: Advanced reporting, automatic virtual patching, dedicated security services and premium add-ons for teams managing many sites.

---

Final thoughts

CVE-2025-0818 is a stark reminder: file management functionality is incredibly powerful and — when implemented incorrectly — extremely dangerous. The fact that this vulnerability allows unauthenticated deletion elevates the urgency. Update the plugin now. If you cannot update instantly, apply virtual patching, disable the plugin or block its endpoints. Review your backups and hardening posture — recovery is often more time-consuming than applying a patch.

We know dealing with security incidents is stressful. If you want help triaging, hardening or remediating an incident, our WP‑Firewall team can assist with virtual patching and managed cleanups to reduce downtime and restore your site safely.

Stay safe, and please treat this as an emergency if your site uses Advanced File Manager <= 5.3.6.

— WP‑Firewall Security Team