Intrusion Tolerance for Networked Systems through Two-Level Feedback Control
This work addresses intrusion tolerance for networked systems, offering a novel control-based approach that is incremental in applying operations research methods to a known bottleneck.
The paper tackles the problem of intrusion tolerance in networked systems by formulating it as a two-level optimal control problem, with local node controllers handling intrusion recovery and a global system controller managing replication. The results show that their TOLERANCE architecture improves service availability and reduces operational cost compared to state-of-the-art systems in emulation tests with 10 types of network intrusions.
We formulate intrusion tolerance for a system with service replicas as a two-level optimal control problem. On the local level node controllers perform intrusion recovery, and on the global level a system controller manages the replication factor. The local and global control problems can be formulated as classical problems in operations research, namely, the machine replacement problem and the inventory replenishment problem. Based on this formulation, we design TOLERANCE, a novel control architecture for intrusion-tolerant systems. We prove that the optimal control strategies on both levels have threshold structure and design efficient algorithms for computing them. We implement and evaluate TOLERANCE in an emulation environment where we run 10 types of network intrusions. The results show that TOLERANCE can improve service availability and reduce operational cost compared with state-of-the-art intrusion-tolerant systems.