Urgent: CVE-2025-7641 — Unauthenticated Path Traversal & Arbitrary Directory Deletion in Assistant for NextGEN Gallery (≤ 1.0.9)

Author: Hong Kong Security Expert   |   Date: 2025-08-16

Summary: A high-severity path traversal vulnerability (CVE-2025-7641; CVSS 7.5) affecting Assistant for NextGEN Gallery plugin versions ≤ 1.0.9 allows unauthenticated attackers to delete arbitrary directories. There is no official patch available at publication. If your site uses this plugin, act immediately to protect data and restore integrity.

Table of Contents

• Executive summary
• What this vulnerability is (high level)
• Technical background and why this is dangerous
• Attack scenarios and likely impact
• Why exploitation is realistic and urgent
• Safe detection: how to check if you’re affected
• Immediate mitigations (step-by-step)
• Long term remediation and secure configuration
• How a Web Application Firewall (WAF) can protect you
• Suggested virtual patch / WAF rule patterns (conceptual)
• Incident response playbook for compromised sites
• For plugin authors: secure coding notes to prevent path traversal and file deletion bugs
• Closing recommendations

Executive summary

On 15 August 2025 a public disclosure (CVE-2025-7641) revealed a path traversal vulnerability in the Assistant for NextGEN Gallery WordPress plugin (versions ≤ 1.0.9). The flaw enables unauthenticated attackers to delete arbitrary directories. Because no authentication is required, remote attackers can target victims at scale and remove directories such as galleries, uploads or other writable folders, causing data loss and potentially prolonged downtime.

This advisory explains the technical risk, how to detect if you’ve been targeted, immediate mitigations to reduce exposure when no vendor patch is available, and longer-term hardening and monitoring guidance from the perspective of a Hong Kong security practitioner.

What this vulnerability is (plain language)

• Type: Path Traversal (directory traversal) enabling arbitrary directory deletion
• Privilege: Unauthenticated — accessible by anyone on the Internet
• Impact: Deletion of directories and files inside the webroot or plugin-managed storage — loss of images, galleries, backups or site files
• CVE: CVE-2025-7641
• Severity: High (CVSS 7.5)
• Affected versions: Assistant for NextGEN Gallery ≤ 1.0.9
• Vendor patch availability: None at time of disclosure

Path traversal occurs when user-supplied path fragments (../ and variants) are not validated, allowing code to escape an intended directory. If the application performs destructive filesystem actions (rmdir, unlink) on those unvalidated paths, attackers can remove arbitrary directories that the webserver process can write to.

Technical background — why directory deletion via path traversal is especially severe

Most path traversal vulnerabilities allow read access to sensitive files. This instance is more dangerous because it enables deletion. Deleted data can be difficult or impossible to recover without reliable offsite backups or snapshots. Key reasons this vulnerability is severe:

• Unauthenticated: No credentials required — attackers can scan and exploit remotely.
• Arbitrary directory deletion: Attackers can target wp-content/uploads, plugin folders, backups, or other writable directories.
• Webserver permissions: The webserver user often has write permissions to plugin and upload directories; deletions executed by the webserver will succeed if permitted.
• Automation potential: Exploit scripts and bots can identify vulnerable sites and execute destructive payloads en masse.

Attack scenarios and likely impact

Examples of plausible exploitation and consequences:

1. Mass removal of media and galleries

   Impact: All gallery images removed; broken pages and degraded user experience. Business consequence: e-commerce images or marketing assets lost, revenue impact.

2. Targeting configuration or plugin directories

   Impact: Plugin state wiped and functionality broken. Business consequence: admin errors, time-consuming reinstall or reconfiguration.

3. Deleting backups

   Impact: Attackers remove backups to prevent recovery. Business consequence: extended downtime and higher recovery costs.

4. Chaining with other vulnerabilities

   Impact: Deletion used as cover to replace files or plant backdoors. Business consequence: persistent compromise and data exfiltration.

5. Induced denial of service

   Impact: Site fails from missing assets or critical folders removed. Business consequence: outage, reputational and SEO damage.

Because the vulnerability is unauthenticated and unpatched, rapid scanning and exploitation are likely.

Why exploitation is realistic and urgent

• Public CVE information and proof-of-concept details increase attacker interest.
• Attackers use automated tooling to discover plugin fingerprints and call vulnerable endpoints.
• Low attacker effort: no auth required and straightforward payloads.
• High payoff: deleting valuable media or backups has high cost to defenders and low cost to attackers.

If you manage multiple WordPress installations or client sites, treat this as an immediate priority.

Safe detection — how to check if you’ve been targeted (what to look for)

Do not attempt active exploitation on production systems. Instead, gather logs and hunt for indicators of compromise (IoCs).

1. Webserver and PHP logs

Search for suspicious requests to plugin endpoints or queries containing traversal tokens. Example commands (adjust paths for your environment):

# Search for suspicious encodings like ../ or %2e%2e
grep -E "(%2e%2e|%2f%2e|%2e%2f|\.\./)" /var/log/apache2/access.log
# Search for plugin-specific endpoints or identifiers
grep -E "assistant-for-nextgen|nextgen-assistant|ngg-assistant" /var/log/apache2/access.log

Look for POST/GET requests to plugin endpoints followed by HTTP 200/204/500 responses around times when files were removed.

2. File system checks

• Look for missing directories under wp-content/uploads or plugin-specific folders.
• Compare the live filesystem to backups or a recent staging copy.
• Check for filesystem snapshots and for recent rmdir/unlink timestamps.

3. WordPress audit logs

If you have activity/audit plugins, search for deletion events. Note: because this is unauthenticated, WordPress user logs may not show related activity.

4. Backup integrity

Confirm offsite backups are intact and not altered. If backups are compromised, expand forensic scope.

5. Unexpected plugin behavior

Check PHP error logs for warnings or failures associated with file operations from the plugin.

6. Network or WAF logs

If you have a WAF or network IDS, review logs for blocked requests containing traversal patterns. Preserve all logs and snapshots for investigation.

If you find evidence of deletion, snapshot the current system and preserve logs before performing restores or sweeping changes.

Immediate mitigations (step-by-step)

When no official patch exists, apply layered controls: stop active exploitation, isolate the vulnerable code, and prepare for recovery.

1. Short-term emergency steps (minutes)

• Deactivate the plugin immediately
  • From WordPress admin: Plugins → deactivate Assistant for NextGEN Gallery
  • Via WP-CLI: wp plugin deactivate assistant-for-nextgen-gallery
  • Or rename the plugin folder via SFTP: wp-content/plugins/assistant-for-nextgen-gallery → assistant-for-nextgen-gallery.disabled
• Restrict access to the site
  • Enable maintenance mode
  • Restrict admin endpoints by IP where feasible until the site is secured

2. Block the vulnerable endpoints at the server level

Create temporary rules to block requests to the plugin’s entrypoints or any requests containing directory traversal patterns (../ and encoded variants). If you operate a WAF or server-level filtering, add blocks for traversal tokens. If you do not have a WAF, add server configuration rules (examples below).

3. Preserve evidence

• Take a full snapshot of the server and filesystem before making changes that may remove forensic data.
• Export webserver, PHP, and application logs.

4. Validate backups and prepare restoration plan

• Verify offsite backups and their integrity.
• Identify the most recent clean restore point and prepare a staged restore process.

5. Scan the site

• Perform a malware and integrity scan from a trusted host or offline copy. Do not rely solely on in-situ plugin scanners if compromise is suspected.
• Search for webshells, unknown files, modified permissions, or anomalous .htaccess entries.

6. Rotate secrets

Rotate admin passwords, API keys and any credentials stored in files or the database if compromise cannot be ruled out.

7. Notify stakeholders

Inform hosting provider, ops team and affected owners per your incident policy.

8. Intensify monitoring

Watch for repeated scans and blocked traversal attempts and increase log retention while the incident is active.

Long term remediation and secure configuration

After immediate containment, follow these steps to reduce future risk:

1. Replace or update the plugin

   Monitor the vendor for an official fix. If the plugin is unmaintained, remove it or replace it with a vetted alternative.

2. Harden file and folder permissions

   Limit write access for the webserver user. Use minimal permissions: directories 755, files 644 where appropriate, and avoid world-writeable flags.

3. Principle of least privilege

   Ensure scheduled tasks and processes run with the minimum privileges needed.

4. Continuous scanning and monitoring

   Implement file integrity monitoring to detect deletions and set alerts for traversal-like requests.

5. Keep software updated

   Patch WordPress core, themes and plugins in a staging environment before applying to production.

6. Backups and restore testing

   Maintain multiple backup retention points and periodically test restores.

7. Security development lifecycle

   For custom code, treat input validation, path canonicalization and unit testing as mandatory.

How a Web Application Firewall (WAF) can protect you

A properly configured WAF provides a useful layer of defence while you remediate and await vendor patches. Relevant protections include:

• Virtual patching: Block exploitation patterns at the edge (e.g., traversal sequences in requests) to buy time until an official fix is available.
• Positive and negative filtering: Whitelist expected parameter formats where possible and block known-bad tokens like ../ and encoded variants.
• Rate limiting and bot protection: Limit automated scanning and mass exploitation attempts.
• File integrity monitoring: Alert on sudden deletions or mass file changes.
• Behavior-based detection: Detect rapid sequences of destructive actions and raise high-priority alerts.
• Temporary access controls: Use IP blacklists/whitelists to restrict access while recovery is underway.

Suggested virtual patch / WAF rule patterns (conceptual — do not implement blindly)

Below are conceptual detection patterns intended for defensive use by administrators and security teams. These are high-level descriptions, not precise rule code.

• Block requests where path or query parameters contain traversal sequences: “../”, “..%2f”, “%2e%2e%2f”, and similar encodings.
• Block requests with null bytes or suspicious encodings near path tokens.
• Block requests to plugin-specific endpoints if the request uses unexpected HTTP methods (e.g., DELETE where only GET/POST are expected).
• Throttle or block rapid sequences of file-operation requests from the same IP or user-agent.
• Whitelist known management IPs for admin endpoints and deny others.

Conceptual nginx guidance (example, non-executable):

# Deny obvious traversal attempts anywhere in the request
if ($request_uri ~* "(%2e%2e|%2f%2e|%2e%2f|\.\./)") {
    return 403;
}
# Additional server-level restrictions: protect WP plugin endpoints
location ~* /wp-content/plugins/assistant-for-nextgen-gallery/ {
    # allow internal admin IPs only (replace with your IP)
    allow 203.0.113.5;
    deny all;
}

Test any rule in staging first; overly aggressive rules can break legitimate functionality.

Incident response playbook — step-by-step if you detect exploitation

1. Isolate

   Block offending IPs at network/firewall level and put the site into maintenance mode.

2. Preserve evidence

   Snapshot disks, export logs and take a full backup of the current state prior to restorations.

3. Assess damage

   Identify deleted or modified directories and determine the most recent clean backup.

4. Clean and restore

   Restore from a known-good backup or selectively restore affected paths. If the compromise is severe, consider a full rebuild from clean sources.

5. Remediate root causes

   Deactivate/remove the vulnerable plugin and replace or patch when the vendor releases a fix.

6. Strengthen defenses

   Deploy edge protections (WAF rules), tighten file permissions and rotate credentials.

7. Post-incident communication

   Notify stakeholders and document the incident timeline and remediation actions.

8. Lessons learned

   Update incident playbooks, monitoring, and testing cadence based on the event.

For plugin authors: secure coding notes to prevent path traversal and destructive filesystem operations

• Never perform filesystem delete operations directly from user-controlled inputs.
• Normalize and canonicalize paths (realpath) and ensure results are inside an allowed base directory.
• Use strict whitelists: accept only identifiers or filenames mapped to server-side safe paths, not raw paths.
• Sanitize inputs: strip path separators, reject encoded traversal tokens and NULL bytes.
• Enforce capability checks: require authentication, authorization and verify nonces before destructive actions.
• Consider a safety net: move items to a quarantine area instead of immediate permanent unlink where feasible.
• Add unit and integration tests for common traversal and edge cases, and provide a clear security reporting channel.

Closing recommendations — a prioritized checklist

1. Immediately deactivate or remove the Assistant for NextGEN Gallery plugin if you use an affected version (≤ 1.0.9).
2. Block plugin endpoints and traversal patterns at server/WAF level.
3. Validate offsite backups and prepare to restore if needed.
4. Search logs for suspicious requests and preserve them for investigation.
5. Audit all WordPress instances you manage and schedule remediation across your environment.
6. Deploy WAF rules that block traversal sequences while you remediate and test carefully in staging.
7. Keep backup and incident response procedures tested and up-to-date.

Final thoughts

Plugins that interact with the filesystem require rigorous input validation and privilege separation. Unauthenticated destructive capabilities are particularly dangerous because they enable automated mass exploitation.

If you need assistance creating server-level rules, performing a safe forensic analysis, or planning a staged restoration from backups, engage an experienced security consultant or your hosting provider’s incident response team. Immediate action — even simple containment steps — can significantly reduce the impact of this vulnerability.

Stay vigilant, verify your backups, and respond quickly.

— Hong Kong Security Expert