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SCADA Security Tutorial

SCADA security tutorial is provided by TONEX to give you overall and general information about Supervisory Control and Data Acquisition (SCADA) and its security aspects. If you are starting to learn this topic or if you are one of those who know their stuff but need to brush up some of the angels of their knowledge, this tutorial is a great help to you.

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SCADA Overview

SCADA, standing for Supervisory Control and Data Acquisition, are applied to oversee and regulate a plant or equipment in industries including telecommunications, water and waste control, energy, oil and gas refining and transportation. Such systems cover the allocation of data between a SCADA central host computer and a series of Remote Terminal Units (RTUs) and/or Programmable Logic Controllers (PLCs), and the central host and the operator terminals. A SCADA system collects data, carries the information back to a central unit, then alarms the home site that a leak has happened, performing required evaluation and control, like identifying the severity of the leak, and demonstrating the data in a rationale and systematic way. These systems can be both simple and very complex. Conventionally speaking, SCADA systems have being used for the Public Switched Network (PSN) in order to monitor the network. Currently, several systems are being overseen by the infrastructure of the commercial Local Area Network (LAN)/Wide Area Network (WAN). Wireless technologies are also being broadly used for the same purposes, i.e. monitoring.

SCADA Systems Components

  • Field data interface instruments, could be one or more, usually RTUs, or PLCs, which interface to field sensing devices and local control switchboxes and valve actuators
  • A communications system employed to carry data between field data interface instruments and control sites and the computers in the SCADA central host. Such system could be radio, telephone, cable, satellite, etc., or any combination of these.
  • A central host computer server or servers (aka SCADA Center, master station, or Master Terminal Unit (MTU)
  • A standard or custom software systems [aka Human Machine Interface (HMI) software or Man Machine Interface (MMI) software] to serve the SCADA central host and operator terminal application, support the communications system, and monitor and control remotely situated field data interface instruments

Field Data Interface Instruments

Field data interface instruments are considered as the “eyes and ears” of a SCADA system. Such instruments such as meters and gauges provide the necessary data based on which an operator could evaluate how well a system is functioning. Moreover, some other equipment acts as the “hands” of the SCADA system, assisting in automating the system processes.

However, all the data and information gathered from various pints and units of the system need to be converted to a language compatible with the SCADA system, in order for the automation or remote monitoring can be accomplished. Therefore, types of electronic field data interface such RTUs, aka Remote Telemetry Units, are required. RTUs are mainly applied to convert electronic signals received from field interface instruments into the communication protocol used to transfer the information through a communication port.

The guideline of the automation of field data interface instruments, such as pump control logic, are often stored locally. This is mainly because of the limited bandwidth of communications connections between the SCADA central host computer and the field data interface instruments. Such guidelines are conventionally assumed within the PLCs, which have previously been separated physically from RTUs. A PLC is a tool to automate monitoring and regulating of industrial facilities. It can be applied an independent or in combination with a SCADA or other system. PLCs link straight to field data interface instruments and integrate programmed intelligence in the form of rationale processes that will be performed in the event of secure field circumstances.

Telemetry has been used with PLCs for remote location to help PLCs substitute communicate switching logic control systems. Hence, using remote signal, or Supervisory Control, became favorable. While only a simple local control program was needed, it got practical to accumulate this program throughout the RTU and carry out the control inside that instrument. Also, conventional PLCs comprised of communications modules that would enable PLCs to document the status of the control program to a computer connected to the PLC or to a distanced computer via a telephone line. PLC and RTU producers therefore compete for the same market.

Communications Network

The goal of communications network is to support the tools by which data can be transmitted between the central host computer servers and the field-based RTUs. The Communication Network addresses the instruments required to transmit information to and from various sites. The mode used can either be cable, telephone or radio.

Central Host Computer

The central host computer or master station most likely includes a single computer or a network of computer servers serving as a man-machine operator interface to the SCADA system. The computers run the data obtained from and sent to the RTU units and demonstrate it to human operators in a way that the operators can operate based on. Operator terminals are linked to the central host computer by a LAN/WAN so that the observing screens and the relevant information can be presented for the operators. Modern SCADA systems are capable of offering high-resolution computer graphics to demonstrate a graphical user interface or imitate screen of the site.

With the improved use of the PCs, the computer networking is routine in the office and thus SCADA systems are now accessible that can network with office-based PCs. Such has provided various opportunities for the connecting of SCADA systems to office-based applications such as GIS systems, hydraulic modeling software, drawing management systems, work scheduling systems, and information databases.

Relevant Software to SCADA Systems

  • Central host computer operating system
  • Operator terminal operating system
  • Central host computer application
  • Operator terminal application
  • Communications protocol drivers
  • Communications network management software
  • RTU automation software

SCADA Architectures

There are three generations of SCADA systems:

  • First Generation – Monolithic
  • Second Generation – Distributed
  • Third Generation – Networked

SCADA Network Components

  • Firewalls
  • Separated SCADA Control Network
  • SCADA General Firewall Policies
  • Domain Name System (DNS)
  • Hypertext Transfer Protocol (HTTP)
  • FTP and Trivial File Transfer Protocol (TFTP)
  • Telnet
  • Simple Mail Transfer Protocol (SMTP)
  • Simple Network Management Protocol (SNMP)
  • Distributed Component Object Model (DCOM)
  • Network Address Translation (NAT)
  • Firewall Issues
  • Data Historians
  • Remote Support Access
  • Multicast Traffic
  • Single Points of Failure
  • Redundancy and Fault Tolerance
  • Preventing Man-in- the-Middle SCADA Attacks
  • SCADA Management Controls

SCADA Protocols

  • IEC 60870-5-101
  • DNP3

Deploying SCADA Systems

  • Twisted-Pair Metallic Cable
  • Coaxial Metallic Cable
  • Fiber Optic Cable
  • Power Line Carrier
  • Satellites
  • Leased Telephone Lines
  • Very High Frequency Radio
  • Ultra High Frequency Radio
  • Microwave Radio

Security and Vulnerability of SCADA Systems

  • Attacks Against SCADA Systems
  • Developing a SCADA Security Strategy
    • Border Router and Firewalls
    • Proxy Servers
    • Operating Systems
    • Applications
    • Policies and Procedures
    • SCADA Firewalls
    • SCADA Internal Network Design
    • SCADA Server Operating Systems
    • SCADA Applications
    • SCADA Policies and Procedures

SCADA Security Components

  • Network Security
  • Ethical Hacking
  • Security Assessment and Authorization

SCADA Standards Organizations

  • The Institute of Electrical and Electronics Engineers (IEEE)
  • American National Standards Institute
  • Electric Power Research Institute
  • International Electrotechnical Commission
  • DNP3 Users Group

How Can You Learn More?

By browsing through our courses in the field of SCADA and SCADA security/cybersecurity, you can find the hands-on training course that fits you best:


SCADA Security Tutorial