To make your site as secure as possible, each user should have an account, with a unique user ID number, and each account should have a password. Users should never give out their passwords to anyone else under any circumstances.
Disable USB Ports
In many companies, the policy is that system administrators on most computers turn off USB ports due to the possibility of inserting unauthorized programs, viruses, scripts and files that can lead to compromising data from the computer.
Internet security is monitored and maintained using a couple of tools that many sysadmins use to secure small but vulnerable holes in their network. Small failures in the implementation of routers, firewalls, virtual private networks and virtual machines can lead to major security problems.
Some free tools for system administrators:
Wireshark, a packet analyzer for sysadmins
KeePass Password Safe, a free open source password manager
Malwarebytes, a free anti-malware and antivirus tool
NMAP, a powerful security scanner
NIKTO, an open source web server scanner
Ansible, a tool for automating secure IT provisioning
Metasploit, a tool for understanding attack vectors and doing penetration testing