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Ashiq Rahman, Ehab Al-Shaer.  Submitted.  Automated Synthesis of Resilient Network Access Controls: A Formal Framework with Refinement. IEEE Transactions of Parallel and Distributed Computing (TPDC),.

Due to the extensive use of network services and emerging security threats, enterprise networks deploy varieties of security devices for controlling resource access based on organizational security requirements. These requirements need fine-grained access control rules based on heterogeneous isolation patterns like access denial, trusted communication, and payload inspection. Organizations are also seeking for usable and optimal security configurations that can harden the network security within enterprise budget constraints. In order to design a security architecture, i.e., the distribution of security devices along with their security policies, that satisfies the organizational security requirements as well as the business constraints, it is required to analyze various alternative security architectures considering placements of network security devices in the network and the corresponding access controls. In this paper, we present an automated formal framework for synthesizing network security configurations. The main design alternatives include different kinds of isolation patterns for network traffic flows. The framework takes security requirements and business constraints along with the network topology as inputs. Then, it synthesizes cost-effective security configurations satisfying the constraints and provides placements of different security devices, optimally distributed in the network, according to the given network topology. In addition, we provide a hypothesis testing-based security architecture refinement mechanism that explores various security design alternatives using ConfigSynth and improves the security architecture by systematically increasing the security requirements. We demonstrate the execution of ConfigSynth and the refinement mechanism using case studies. Finally, we evaluate their scalability using simulated experiments.
 

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Ashiq Rahman, Ehab Al-Shaer.  2016.  Formal Analysis for Dependable Supervisory Control and Data Acquisition in Smart Grids. The 46th IEEE/IFIP International Conference on Dependable Systems and Networks (DSN).

Smart grids provide innovative and efficient energy management services that offer operational reliability. The Supervisory Control and Data Acquisition (SCADA) system is a core component of a smart grid. Unlike the traditional cyber networks, these components consist of heterogeneous devices, such as intelligent electronic devices, programmable logic controllers, remote terminal units, control servers, routing and security devices, etc. SCADA devices communicate with one another under various communication protocols, physical media, and security properties. Failures or attacks on such networks have the potential of data unavailability and false data injection causing incorrect system estimations and control decisions leading to critical damages including power outages and destruction of equipment. In this work, we develop an automated security and resiliency analysis framework for SCADA in smart grids. This framework takes smart grid configurations and organizational security and resiliency requirements as inputs, formally models configurations and various security constraints, and verifies the dependability of the system under potential contingencies. We demonstrate the execution of this framework on an example problem. We also evaluate the scalability of the framework on synthetic SCADA systems.

Ashiq Rahman, Ehab Al-Shaer.  2016.  Formal Analysis for Dependable Supervisory Control and Data Acquisition in Smart Grids. The 46th IEEE/IFIP International Conference on Dependable Systems and Networks (DSN).

Smart grids provide innovative and efficient energy management services that offer operational reliability. The Supervisory Control and Data Acquisition (SCADA) system is a core component of a smart grid. Unlike the traditional cyber networks, these components consist of heterogeneous devices, such as intelligent electronic devices, programmable logic controllers, remote terminal units, control servers, routing and security devices, etc. SCADA devices communicate with one another under various communication protocols, physical media, and security properties. Failures or attacks on such networks have the potential of data unavailability and false data injection causing incorrect system estimations and control decisions leading to critical damages including power outages and destruction of equipment. In this work, we develop an automated security and resiliency analysis framework for SCADA in smart grids. This framework takes smart grid configurations and organizational security and resiliency requirements as inputs, formally models configurations and various security constraints, and verifies the dependability of the system under potential contingencies. We demonstrate the execution of this framework on an example problem. We also evaluate the scalability of the framework on synthetic SCADA systems.
 

Ashiq Rahman, Ehab Al-Shaer.  2015.  Formal Synthesis of Dependable Configurations for Advanced Metering Infrastructures. IEEE SmartGridComm'15 Symposium - Security and Privacy.

he Advanced Metering Infrastructure (AMI) in a smart grid comprises of a large number of smart meters along with heterogeneous cyber-physical components. These components communicate with each other through different communication media, protocols, and delivery modes for transmitting usage reports and control commands to and from the utility. There is potential for dependability threats especially due to misconfigurations, which can easily disrupt the operations in AMI. Therefore, an AMI must be configured correctly. In this paper, we present an automated configuration synthesis framework that mitigates potential threats by eliminating mis-configurations. We have manifold contributions in this research: (i) formal modeling of AMI configurations including AMI device configurations, topology and communication properties, and data flows among the devices; (ii) formal modeling of AMI operational integrity properties considering the interdependencies among AMI devices' configurations; and (iii) implementing the model using Satisfiability Modulo Theories (SMT), execution of which synthesizes necessary AMI configurations. We demonstrate the proposed framework on an example case study and evaluate the scalability of the framework on various synthetic AMI networks.