Addressing ICS Security Challenges using Simplex Architecture

Safety-critical services managed by Industrial Control Systems (ICS) are now far more exposed to external threats. Security frameworks that ensure that the physical systems are fail-safe when compromised due to unforeseen vulnerabilities such as zero-day exploits are desired. We survey security challenges and mitigation strategies used for protecting ICS. We explore different types of vulnerabilities and elucidate how they have been exploited in the past. We identify key ICS attributes that differentiate them from traditional IT systems deployed in enterprise networks. Further, we show how these attributes can be used by designing a security framework based on Simplex Architecture. We evaluate this framework on an ICS testbed and demonstrate its effectiveness in ensuring the safety of the physical process system even under external attacks.