|
Research Projects Secure Internetworked Control Systems The connectivity between control networks and internetworks, such as the Internet and enterprise networks, is an important trend for process control systems. The connectivity improves efficiency of system management, reduces cost by using commercial technologies, and provide increased visibility of the process to the enterprise. However, the connectivity introduces serious cyber security threats, which were not significant in control networks since most systems relied on physical isolation. A basic solution is to apply existing security mechanisms for internetworks to control networks directly. However, some solutions often don't address the security vulnerabilities completely and efficiently. For example, firewalls and VPNs are error prone due to human errors and provide only coarse-grained access control enforcement. Because the two networks have different purposes, the mechanisms can not handle some special requirements of control systems, such as timing constraints. Furthermore, current solutions do not address the security of future applications inspired by the connectivity between control networks and internetworks. Therefore, common security solutions may not be appropriate for control networks. We claim End-to-End(E2E) security is a feasible approach to improve security of internetworked control systems. By E2E security, control devices have built-in security features. They can communicate independently and securely with other entities over internetworks. Authentication and authorization can be flexibly enforced on each device. E2E security can provide network assurance that guarantees secure message transmission with the concern of special requirements of process control, such as authenticated communications with desired latency, and prevent DoS vulnerabilities introduced by the connectivity. At the application layer, E2E trust is used to address authenticity and integrity of entities inside or outside of control networks. It is control system specific and bi-directional. Remote hosts can assess control device configurations; control devices can verify authenticity of remote hosts or other control devices. Based on E2E trust, a uniform authorization scheme can be used for fine-grained access control. To achieve these goals, the proposal presents an E2E Control Network Architecture (E2E-CNA). We propose a Network Security Hub (Network Hub) to guarantee network assurance. By "inverted" hub-and-spokes communication scheme, which is based on existing security protocols, such as IPSec, Network Hub provides secure tunnels for timing critical communications within a process control network. Network Hub also behaves as a gateway to maintain secure tunnels across control networks and internetworks. We introduce Authentication & Authorization Hub (AA Hub) to realize E2E trust. Working with trust modules on each control device, it verifies credentials bi-directionally and enforces Attribute-Based Role Assignment access control policies. E2E-CNA is policy driven. Policies for secure communication and fine-grained access control are defined by centralized security hubs and then enforced by individual control devices.
End-to-End Control Network Architecture We validate E2E-CNA with case study of power substation networks. Network Hub and AA Hub are implemented and deployed in a substation network test bed. Secure Intelligent Electronic Devices (SIEDs) are implemented with full features of E2E security; including modules of IPSec based substation communications and distributed authorization. Internet traffic and substation network traffic are emulated and analyzed under four basic scenarios: unloaded traffic, loaded traffic across internetworks, resilience on DoS attacks and combined traffic. Besides setting up our own test-bed for preliminary test, we also emulate a medium size control network via Deterlab. All validation scenarios are based on power substation network communication specifications, such as IEC61850. Concerning both cyber security and domain specific requirements of control networks, E2E-CNA implements E2E security for internetworked control systems. By integrating and enhancing existing security mechanisms, E2E-CNA enables control devices to be connected to internetwork directly in a secure manner. This achieves a real connection between control networks and internetworks. Past Projects
Publications Thesis and Papers
Book Chapters
Reports and Drafts
Presentations and Posters
Other Academia Activities
|
||||||||||||||||||||||||||||||||||||||||||||||||||
