Critical Infrastructure Security: Securing Field Communication Report

This report addresses the critical importance of securing field communication within Industrial Control Systems (ICSs) and Supervisory Control and Data Acquisition (SCADA) systems, emphasizing the significance of robust authentication and authorization mechanisms to prevent unauthorized access and exploitation. The report suggests and explains three key methods for securing field communication. Firstly, it recommends the implementation of IPsec to establish secure communication tunnels, ensuring data confidentiality, integrity, and sender authentication. Secondly, the Modicon communication protocol is proposed for its efficient and secure communication capabilities, particularly at layer 7 of the OSI model. Finally, the distributed network protocol (DNP3) is presented as a means to provide secure communication between master stations and outstations, especially in environments with high electromagnetic interference. The report emphasizes the importance of using version 5 of DNP3 and implementing it from the physical to the network layer to minimize computing load. The report includes citations from various sources to support its claims.

Running head: CRITICAL INFRASTRUCTURE SECURITY
Critical Infrastructure Security
Name of the Student
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Author Note

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Importance of Authentication and Authorization
For the ICSs and SCADA systems, one of the main aspects is how a user is interacting with
the resources (such as remote server and local application) to ensure that the interaction
session has no problem and for this reason, proper authentication and authorization are
needed. When the system of ICSs and SCADA are having the mechanism of authentication
and authorization, it becomes difficult for the attackers to identify the system and to exploit
the system (Bartman & Carson, 2016). The hacker or the attacker faces difficulty to exploit
the system because integration of the authentication and the authorization in the ICSs and
SCADA systems lock down all of the services of the system to some specific individuals or
to some specific group of users so that the hackers are unable to access the resources of the
system. As the further access to the resources is restricted, performing an attack in the ICSs
and SCADA systems becomes very much difficult for the hackers (Hummen et al., 2014).
Also, there are various levels of authentication and authorization in the ICSs and SCADA
systems. A higher level of authentication and authorization means more security to the
system but also increases the complexity of the system.
Suggestion and Explanation for Securing field communication
For securing the field communication in the first section implementation of the IPsec can be
considered. The IPsec is suggested for securing field communication in the SCADA, and the
ICSs systems IPsec successfully builds a secure tunnel for the communication process among
two endpoints. Using the IPsec secret keys can be exchanged safely between the two
endpoints. When the communication channel is established using the IPsec protocol the
receiver, and the sender agrees on a particular type of encryption algorithm which will be
used for secure communication. For the secure field communication, IPsec uses the protocols
of confidentiality, message integrity and sender authentication. Wrapping the SCADA traffics

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of the industries in a protective IPsec will help to ensure secure communication between the
gateway and endpoint devices (Nan, Eusgeld & Kröger, 2013). The IPsec can be
implemented in two ways, first is the end-host implementation and the second one is the
router implementation. In the end-host implementation, the protocols of the IPsec will be
applied to all types of host devices that will provide end-to-end security between any two
networks (Singh & Singh, 2013). The implementation of the router technique is used less
compared with the end-host implementation. This is implemented less because it needs to
make more changes to only some few routers instead of thousands of clients. This
implementation procedure is able to give protection only between pairs of routers which
might be sufficient in certain cases, but in most of the cases, this type of implementation of
the IPsec is ignored.
In the next case the Modicon communication is suggested for the securing the field
communication in the SCADA and ICA system. The Modicon is suggested for securing the
field communication because it is able to provide efficient and secure communication using
the reply/request methodology between some interconnected assets. The Modicon operates at
layer 7 of the OSI model, and that is the main reason for its effective communication. Also,
due to this layer 7, the protocol of the Modicon is able to work independently. In the process
of the communication, Modicon allows extremely simple devices to communicate with the
variety of complex computers through a secure communication channel. Thus by the
implementation of this protocol both effective and secure communication is achieved. This
protocol can be implemented for the SCADA in RS-485 or in the RS-232C physical layer. At
most 32 number of devices can be implemented on a single RS-485 serial link. Compared
with the RS-485 the implementation of the RS-232C is very much easier to commission. In
the implementation of the RS-485, a command is addressed to a specific address to the

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Modicon address and in this case when other devices will receive the message only the
addressed device will be able to respond in this system.
The last suggestion for the secure field communication is the distributed network protocol.
This protocol provides secure communication between the master station and the outstations.
Secure communication is achieved through this protocol because this protocol commonly
connects by using the RTUs configuration. This protocol of the distributed network is based
on the IEC-60870-5 standard (Knapp & Langill, 2014). This protocol provides a secure and
reliable field communication in the high level of electromagnetic interference environment
and in poor transmission media. This level of secure and reliable field communication is
achieved as the distributed network protocol is able to work over IP via encapsulation in UDP
or TCP packets (Lee et al., 2013). The secure distributed network protocol is also considered
as the DNP3 variant which adds authentication for responding to a particular process. Also,
while the DNP3 is used for secure communication, it is suggested to use only the version 5
DNP3. The DNP3 or the distributed network protocol is implemented in the system from the
physical layer to the network level at the level of the hardware. This is implemented for
reducing the computing load on the CPU.

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References
Bartman, T., & Carson, K. (2016, April). Securing communications for SCADA and critical
industrial systems. In Protective Relay Engineers (CPRE), 2016 69th Annual
Conference for (pp. 1-10). IEEE.
Hummen, R., Shafagh, H., Raza, S., Voig, T., & Wehrle, K. (2014, June). Delegation-based
Authentication and Authorization for the IP-based Internet of Things. In Sensing,
Communication, and Networking (SECON), 2014 Eleventh Annual IEEE
International Conference on (pp. 284-292). Ieee.
Knapp, E. D., & Langill, J. T. (2014). Industrial Network Security: Securing critical
infrastructure networks for smart grid, SCADA, and other Industrial Control Systems.
Syngress.
Lee, J., Conti, A., Rabbachin, A., & Win, M. Z. (2013). Distributed network secrecy. IEEE
Journal on Selected Areas in Communications, 31(9), 1889-1900.
Nan, C., Eusgeld, I., & Kröger, W. (2013). Analyzing vulnerabilities between SCADA
system and SUC due to interdependencies. Reliability Engineering & System
Safety, 113, 76-93.
Singh, P. K., & Singh, P. P. (2013). A Novel approach for the Analysis & Issues of IPsec
VPN. International Journal of Science and Research, 2(7), 187-189.