To secure your company’s network and prevent unauthorized access to sensitive data:

1. Review all user access privileges.
2. Implement a two-factor authentication policy for known users.
3. Regularly scan for network vulnerabilities to patch any security holes.
4. Keep your systems up to date with the latest security patches.
5. Backup all important data and store the copies offsite in case of an emergency.
6. Invest in a reliable firewall and cryptograph protection for your data.
7. Consider implementing an intrusion detection system for regular traffic monitoring.
8. Educate staff on cyber security best practices.