No security policy or system is ever foolproof. Here are a few vulnerabilities to watch out for:

• Are policies and procedures adequate and applicable? IT security methods cannot be applied without adaptions for control level and overall automation security objectives.
• Have you deployed “defense in depth?” Securing a control system requires a systematic and comprehensive approach. Simply installing a firewall or a virus scanner does not achieve protection. Seek “defense in depth.”
• Is your remote access secure? Data availability must be ensured as well as controlled. When outside/Web access is established, deploy strong control policies, tools, and processes that prevent unauthorized access.
• Is your wireless open to intruders? Wireless communication is becoming more important. Industrial use of radio technology requires state-of-the-art authentication and encryption combined with high-quality encryption keys.
• Is resource-sharing opening your system to attack? HMI and control networks should not share communication resources or bandwidth with non-essential services. System design should segregate networks appropriately.
• Have all unnecessary and inappropriate applications been removed? Only necessary applications directly involved in process control should reside on the system. Email, games, media players, etc., should be removed and not reintroduced.
• Is your firewall configured correctly? One common security mistake is believing that you are protected because you have a firewall. Many owner / operator’s systems were breached because their firewalls were not configured correctly. Enlist personnel with expertise in both process control and IT when establishing firewalls.