Incident response checklist — if you suspect compromise

1. Contain
   • Place the site in maintenance mode if necessary.
   • Isolate the host or disable the vulnerable plugin until patched and cleaned.
   • Deploy WAF rules to block suspected exploit vectors.
2. Preserve evidence
   • Take full backups and filesystem snapshots for analysis.
   • Save webserver access logs and application logs.
   • Export the database.
3. Identify and remove malicious artifacts
   • Sanitize options, posts, postmeta and plugin custom tables to remove stored payloads.
   • Search for new admin users, backdoor PHP files, suspicious scheduled tasks (wp_cron), or modified theme/plugin files.
   • Quarantine or remove unfamiliar files.
4. Patch
   • Update PixelYourSite to 11.2.0.1 or later.
   • Update WordPress core, PHP and other plugins/themes to supported versions.
5. Recover
   • Rotate admin passwords and API keys.
   • Force logout all sessions.
   • Reissue credentials for third‑party integrations if necessary.
6. Monitor
   • Increase monitoring for several weeks: WAF logs, file integrity monitoring, admin activity.
   • Check Google Search Console for suspicious indexing or spam.
7. Notify
   • If sensitive data may have been leaked, follow applicable notification laws and inform stakeholders.

Longer-term hardening and prevention

• Keep WordPress core, plugins and themes up to date. Enable auto-updates for critical security patches where appropriate.
• Limit admin access by IP and enforce strong authentication (2FA) for admin accounts.
• Apply principle of least privilege — grant capabilities only as required.
• Implement Content Security Policy (CSP) to reduce the impact of XSS; a properly configured CSP can prevent execution of unauthorized inline scripts.
• Ensure cookies use Secure, HttpOnly and appropriate SameSite attributes.
• In custom code, always use proper escaping functions: esc_html(), esc_attr(), esc_js(), wp_kses() as appropriate.
• Avoid storing arbitrary HTML unless necessary; if storing HTML, whitelist allowed tags using wp_kses().
• Protect administrative endpoints with IP restrictions or additional authentication layers where feasible.
• Maintain robust backups with tested restore procedures and regular integrity checks.
• Regularly scan for malware and unauthorized changes (file integrity monitoring).

Testing and validation

• After patching and applying WAF rules, test admin screens and plugin settings as trusted users to ensure functionality.
• Validate that WAF rules do not block legitimate plugin operations; tune allowlists where required.
• Perform targeted penetration testing or XSS scans in a staging environment to validate protections.
• Use CSP reporting to observe blocked inline scripts and refine policies iteratively.

Sample minimal CSP header (tune to your site):

Content-Security-Policy: default-src 'self' https:; script-src 'self' 'nonce-' https://trusted-analytics.example.com; object-src 'none'; base-uri 'self';

Note: CSP implementation requires careful testing and nonce management for inline scripts.

Final notes and recommended next steps

1. Immediately verify whether PixelYourSite is installed and its version. If ≤ 11.2.0, update to 11.2.0.1 or later.
2. If immediate patching is not possible, deactivate the plugin, restrict admin access, and deploy WAF rules to mitigate exploitation.
3. Run the detection queries above across your DB and filesystem; remove any malicious payloads you discover.
4. Rotate admin credentials, enable 2FA, and monitor logs closely for the next 30 days.
5. Consider adding CSP and other hardening measures as defense in depth.

If you require assistance deploying WAF rules, scanning for stored payloads, or conducting incident response, engage a trusted security consultant or your hosting provider's security team. From a Hong Kong security perspective: act promptly, prioritise patching, and ensure evidence preservation when investigating incidents.

— Hong Kong Security Expert