Keep your WHMCS software and theme up to date. Developers frequently release updates that include security patches to address vulnerabilities.
Only use themes from reputable sources, such as the WHMCS Marketplace or trusted third-party developers. Avoid using pirated or nulled themes, as they may contain malicious code.
Ensure that you use strong, unique passwords for your WHMCS admin area, FTP, and any other relevant accounts. Consider implementing two-factor authentication for an extra layer of security.
Restrict access to the WHMCS admin area by whitelisting specific IP addresses or using IP-based restrictions. This prevents unauthorized users from accessing sensitive information.
Regularly monitor access logs, error logs, and other system logs for any suspicious activity. This can help you identify and respond to security threats in a timely manner.