Urgent: CSRF in “Restore Permanently delete Post or Page Data” (<= 1.0) — What WordPress Site Owners Must Do Now

As a Hong Kong security expert with experience in web application and WordPress incident response, I have reviewed public reports about a CSRF-related issue in the “Restore Permanently delete Post or Page Data” plugin (versions <= 1.0). This advisory explains what the problem is, why even a “low” severity deserves attention, and the concrete actions administrators and site owners should take immediately.

Executive summary (plain language)

• What happened: The plugin allows requests that restore or permanently delete posts/pages to be accepted without proper request validation.
• Immediate risk: An attacker could cause privileged operations by tricking a logged-in admin into visiting a page (CSRF), or—if the endpoint lacks authentication—by sending direct requests that the plugin accepts. This can cause unwanted restores or permanent deletions.
• Severity: Rated Low (CVSS 4.3). The impact targets content operations (not code execution), but content loss and editorial disruption are real risks.
• Short-term mitigation: If the plugin (≤ 1.0) is present, disable it immediately where practicable. Otherwise, block access to the plugin’s admin endpoints (via server or gateway rules), or add short-term defensive checks (nonces, capability checks) at the application level.
• Long-term: Reinstall only a fixed, verified plugin version from a trusted source. Maintain backups, role audits, and monitoring to limit damage from content changes.

How the vulnerability works (technical, non-exploitative)

Cross-Site Request Forgery (CSRF) occurs when an attacker tricks a user’s browser into submitting a request to a site where the user is authenticated. WordPress mitigations normally include:

• Nonces (wp_nonce_field(), wp_verify_nonce()) to ensure the request originates from the intended UI.
• Capability checks (current_user_can()) to ensure the actor is authorized.
• Ensuring sensitive operations are only callable by authenticated admin paths.

Reports indicate the plugin’s restore/permanent-delete operations lack proper request validation—missing nonce verification and/or capability checks. Two failure modes exist:

1. An admin-facing action lacks a nonce check. An attacker can craft a page that causes an admin’s browser to submit the destructive request (classic CSRF).
2. The endpoint may not require authentication or proper capability checks. If true, requests from unauthenticated actors could perform privileged actions—this is broken access control rather than pure CSRF.

Either failure enables unwanted restores or permanent deletions, potentially resulting in content loss and operational disruption.

Who is affected?

• Sites running the “Restore Permanently delete Post or Page Data” plugin at version 1.0 or earlier.
• Administrators, editors, or any privileged user whose browser could be tricked into issuing requests.
• Multisite installs that have the plugin activated network-wide.

If you do not use this plugin, you are not affected.

Practical immediate actions (step-by-step)

Follow these prioritized steps now. Start with the fastest mitigations and move to additional protections.

1. Inventory and identify
   • Check each site for the plugin: Admin → Plugins → Installed Plugins.
   • CLI: wp plugin list | grep -i “restore”
   • Note version numbers; versions <= 1.0 are reported vulnerable.
2. Quick stop: disable the plugin (recommended)
   • Dashboard → Plugins → Deactivate the plugin.
   • CLI: wp plugin deactivate <plugin-slug>
   • Rationale: removing the plugin removes the vulnerable code path immediately.
3. If you cannot disable the plugin (business constraints)
   • Block direct access to the plugin’s admin endpoints at the server, CDN, or gateway level (e.g., restrict POSTs to the plugin URLs).
   • Restrict access to /wp-admin or specific plugin pages by IP or HTTP authentication where feasible.
   • Apply request filtering that enforces presence of valid WordPress nonces and expected headers for sensitive actions.
4. Short-term code hardening

   Add a small defensive mu-plugin or site-specific check to validate nonces and capabilities before allowing restore or permanent-delete operations. An example is provided below; adapt it to the plugin’s action names and parameters.

5. Backups and verification
   • Ensure you have recent, restorable backups. Take a new backup immediately.
   • If you find unauthorized deletions, prepare to restore from a clean backup.
6. Monitor and investigate
   • Review wp_posts changes, audit logs, and server logs for suspicious activity.
   • Look for restores (trash → publish), sudden deletions, or unexpected attachment removals.
7. Update or remove permanently
   • When a secure plugin update is released, validate the fix on staging before updating production.
   • If the plugin is unmaintained, remove it and find alternative, maintained solutions.

Defensive code snippet (safe example)

Add this as a temporary mu-plugin (recommended) or to your theme’s functions.php while you implement other mitigations. Adjust the parameter keys and nonce action to match the plugin’s implementation. If you are not comfortable editing PHP, engage a qualified developer.

<?php
/*
Plugin Name: Temporary CSRF Defense for Restore/Delete Actions
Description: Intercepts requests that attempt to restore or permanently delete posts and validates WP nonces and capabilities.
Version: 1.0
Author: Hong Kong Security Expert
*/

add_action('init', function() {
    // Only inspect POST requests
    if ( 'POST' !== $_SERVER['REQUEST_METHOD'] ) {
        return;
    }

    // Identify plugin-specific parameters that indicate a restore/permanent-delete action.
    // Update these keys to match the plugin's form fields or action names.
    $suspicious = false;
    $keys = array('restore_post_id', 'permanent_delete_post_id', 'action');

    foreach ($keys as $k) {
        if (!empty($_REQUEST[$k])) {
            $suspicious = true;
            break;
        }
    }

    if (!$suspicious) {
        return;
    }

    // 1) Require WP nonce (adjust the second parameter to the plugin's nonce action)
    $nonce_valid = false;
    if (!empty($_REQUEST['_wpnonce']) && wp_verify_nonce($_REQUEST['_wpnonce'], 'wp-restor-delete-action')) {
        $nonce_valid = true;
    }

    // 2) Require current user capability (admins or editors)
    $cap_ok = current_user_can('edit_others_posts') || current_user_can('publish_posts');

    // 3) Optionally verify referer header to reduce CSRF risk (not foolproof)
    $referer_ok = true;
    if (empty($_SERVER['HTTP_REFERER']) || parse_url($_SERVER['HTTP_REFERER'], PHP_URL_HOST) !== $_SERVER['HTTP_HOST']) {
        $referer_ok = false;
    }

    // If any of the checks fail, block the request.
    if (!($nonce_valid && $cap_ok && $referer_ok)) {
        status_header(403);
        wp_die('Unauthorized request blocked.');
    }
}, 1);
?>

How to use:

• Save as a file named mu-csrf-defender.php and place it in wp-content/mu-plugins/ (create the directory if needed).
• Adjust the $keys array and the nonce action string to match the plugin’s parameters and nonce action.
• This is a temporary mitigation. Replace with a plugin-native fix when available.

Why WAF / request filtering helps immediately

When a plugin has no official patch, removing it is the safest option. If removal is not possible immediately, server-level or gateway filtering can reduce risk by blocking known malicious request patterns before they reach WordPress:

• Block or drop POSTs to the plugin’s admin endpoints unless they contain valid nonces or expected headers.
• Enforce referer or origin checks for admin actions where practical.
• Rate-limit or block suspicious IPs attempting to call deletion/restore endpoints.

These measures are mitigations, not substitutes for an official plugin fix. They reduce the attack surface while you arrange for an update or removal.

Detecting whether your site was targeted or exploited

If you run the vulnerable plugin, check these indicators:

1. Audit logs
   • Look for post restore and permanent delete events, including IP addresses and timestamps.
2. Database checks
   • Query wp_posts for recent changes: restore events (post_status from trash to publish), unexpected deletions, or missing attachments.
   • Example: SELECT * FROM wp_posts WHERE post_modified >= '2025-08-15' ORDER BY post_modified DESC;
3. Server access logs
   • Review logs for POST requests to admin-post.php, wp-admin/admin-ajax.php, and any plugin-specific endpoints. Look for unusual POST parameters or unknown IPs.
4. Media and attachments
   • Check wp_postmeta and wp_posts for missing attachments or unexpected metadata changes.
5. Backups
   • Compare backups to the live site; if content is missing, restore from a clean snapshot.
6. Indicators of compromise
   • Sudden author changes, mass content deletion/creation, or changes in scheduled posts are red flags.

If you detect exploitation: isolate the site (take it offline if necessary), preserve logs and database snapshots, restore from a clean backup, rotate admin credentials, and involve a developer or incident response specialist.

Longer-term hardening (best practices)

• Principle of least privilege: Limit administrative roles. Use Editor or Author roles for daily content tasks. Remove unused admin accounts.
• Two-factor authentication: Enforce 2FA for accounts with elevated privileges.
• Enforce nonces and capability checks: Plugin authors must use wp_nonce_field() and wp_verify_nonce(), and always check current_user_can() before privileged actions.
• Backups and test restores: Maintain automated backups and regularly verify restores.
• Application-level logging and monitoring: Keep audit logs for content operations and alert on abnormal delete/restore spikes.
• Secure staging/testing: Test updates and security fixes on staging before production rollout.
• Plugin lifecycle management: Remove outdated or unmaintained plugins and prefer actively maintained solutions.
• Gateway-level filtering: Use server/CDN/gateway rules to block obvious exploit patterns until a fix is available.

Recommended remediation checklist (quick reference)

• Identify all instances of the vulnerable plugin (≤ 1.0).
• Deactivate the plugin immediately, if possible.
• If not possible, enable server/CDN/gateway rules to block restore/delete actions or apply the defensive mu-plugin snippet above.
• Ensure you have a fresh backup; take one now.
• Review audit logs and server logs for suspicious activity.
• Rotate admin passwords and enforce 2FA.
• Monitor for a fixed plugin version; validate the fix on staging and update when safe.
• If heavy activity or data loss is detected: isolate the site, preserve logs, restore from backup, and follow incident response steps.

Example scenario (high level)

An attacker crafts a webpage containing a hidden form or resource that triggers a POST to the vulnerable plugin endpoint. If an admin visits while logged in, the browser sends cookies and the request is executed. Without nonce or capability checks, the server may accept the request and permanently delete content. If the endpoint accepts unauthenticated requests, the attacker can call it directly and scale the attack across many sites.

Frequently asked questions

Q: The vulnerability is rated “Low.” Should I still care?
A: Yes. “Low” refers to the CVSS numeric score but not to business impact. Content loss, editorial disruption, and reputational harm are valid concerns.

Q: Is there an official fix?
A: As of the publication date there is no official fixed plugin release available. Temporary mitigations (disable, server-level blocking, mu-plugin checks) are essential.

Q: Will disabling the plugin break my site?
A: It depends on usage. Deactivating may remove a convenience feature but is safer than running vulnerable code. Back up before making changes.

Q: I don’t have gateway filtering. Can I still protect my site?
A: Yes — fastest options are: disable the plugin, add the defensive snippet as an mu-plugin, restrict admin access by IP, and ensure backups and monitoring are in place. Engage a developer if needed.

Q: Can logs prove if an attacker exploited this?
A: Logs and audit trails can show suspicious POST traffic and changes in wp_posts. Absence of logs does not guarantee absence of exploitation; preserve logs and investigate thoroughly.

Final thoughts and priorities

1. If you run the plugin (≤1.0): disable it now if you can. If not, apply server/CDN/gateway rules or the defensive mu-plugin above.
2. Confirm backups and monitoring are functional. Backups are usually the fastest recovery method.
3. Minimize roles and enforce 2FA for admin accounts.
4. If you need assistance implementing mitigations, engage a qualified developer or a reputable security consultant experienced with WordPress incident response.

Stay vigilant — a “low” severity score should not cause complacency when content integrity and availability are at stake.

— Hong Kong Security Expert