Improving security in SCADA systems through firewall policy analysis

SCADA, network firewalls, network security, network policy, SAT/SMT, firewall rule based analysis

Many of modern SCADA networks are connected to both the company's enterprise network and the Internet. Because these industrial systems often control critical processes the cyber- security requirements become a priority for their design. This paper deals with network communication security in SCADA environment implemented by firewall devices. We proposed a method for verification of firewall configurations against security policy to detect and reveal potential holes in implemented rule sets. We present a straightforward verification method based on representation of a firewall configuration as a set of logical formulas suitable for automated analysis using SAT tools. We demonstrate how such configuration can be analyzed for security policy violation that can be inferred from security policy specification of an industrial automation system.