Supervision and data collection (SCADA systems) is a control system architecture that uses computers, network data transmission tools and graphical user interfaces to control high-level processes. Other peripheral devices are also used, such as programmable logic controllers and discrete PID controllers to interact with a process plant or equipment. Operator interfaces that allow you to control and issue process commands (changes to the control point of the controller) are processed through the SCADA computer system. However, real-time control logic or controller calculations are performed by network modules that connect to field sensors and actuators.
SCADA concept
The SCADA concept was developed as a universal way of remote access to many local control modules, which can be from different manufacturers, providing access through standard automation protocols. A review of SCADA systems shows that this software is very similar to distributed control systems , but using many ways to interact with the installation. They can manage large-scale processes, which can include multiple sites, and work over long distances. This is one of the most commonly used types of industrial control systems, but there are concerns that SCADA executive systems are vulnerable to cyber warfare / cyber terrorism attacks.
SCADA systems - what is it?
A key attribute of the SCADA system is its ability to perform supervisory operations on many other proprietary devices. The accompanying diagram is a general model that shows the functional levels of production using computerized control.
Functional levels of production management operations:
- Level 0 - field devices (flow and temperature sensors) and end controls (control valves).
- Level 1 - Industrial input / output (I / O) modules and associated distributed electronic processors.
- Level 2 - control computers that collect information from processor nodes in the system and provide operator control screens.
- Level 3 - the level of production control, which does not directly control the process, but is engaged in monitoring production and goals.
- Level 4 - production planning level.
Examples of using
Both large and small SCADA intouch systems can be built using the SCADA concept.
These systems can vary from a few tens to several thousand control loops depending on the application. The development of SCADA systems includes industrial, infrastructure and object-oriented processes:
- Industrial processes include production, process control, power generation, manufacture and refining and can operate in continuous, batch, repetitive or discrete modes.
- Infrastructure processes can be public or private, and also include the treatment and distribution of water, the collection and treatment of wastewater, oil and gas pipelines, the transmission and distribution of electricity and wind farms.
- Facility processes, including buildings, airports, ships, and space stations. They control heating, ventilation and air conditioning systems, access and energy consumption.
Nevertheless, SCADA systems may have security vulnerabilities, so risks and solutions that increase the level of security should be evaluated.
Signal processing
An important part of most SCADA system implementations is alarm processing. The system monitors whether certain alarm conditions are met to determine when an event occurred. Once an event is detected, one or more actions are taken (for example, activating one or more alarm indicators and, possibly, generating e-mails or text messages to inform control operators or remote SCADA operators). In many cases, the SCADA operator will have to acknowledge a violation or failure.
Alarm conditions can be explicit - for example, an alarm point is a digital status point that has either NORMAL or ALARM, which is calculated using a formula based on values ​​at other analog and digital points - or implicit: the SCADA system can automatically control whether value at the analog point beyond the high and low values ​​associated with this point.
Examples of alarm indicators include a siren, a pop-up window on the screen, or a colored or flashing area on the screen (which can act similarly to the “fuel tank in a car” light). In each case, the role of the alarm indicator is to draw the attention of the operator to a part of the system “in alarm” so that appropriate actions can be taken.
Commercial Integration and the Perspective of SCADA Systems
Since 1998, almost all major manufacturers have been offering integrated SCADA systems, many of which use open and generic communication protocols. Many specialized third-party packages that offer built-in compatibility with most large systems have also entered the market, allowing mechanical engineers, electrical engineers, and technicians to configure the protocols themselves, without the need for a special program written by a programmer. The remote terminal connects to the physical equipment and converts the electrical signals from the equipment to digital values, such as an open / closed state from a switch or valve, or measurements (pressure, flow, voltage or current).
Communication Infrastructure and Methods
Scada supervisory systems and data collection systems have traditionally used combinations of radio and direct wired connections, although SONET / SDH is also often used for large systems such as railways and power plants. The remote control or monitoring function of the Scada executive system is often referred to as telemetry. Some users want SCADA data to travel across predefined corporate networks or share the network with other applications. However, the legacy of early low bandwidth protocols remains.
SCADA Logging
SCADA protocols are designed very compactly. Typical legacy SCADA protocols include Modbus RTU, RP-570, Profibus, and Conitel. These communication protocols, with the exception of Modbus (Modbus was opened by Schneider Electric), are specific to SCADA suppliers, but are widely used. The standard protocols are IEC 60870-5-101, 104, IEC 61850 and DNP3. These communication protocols are standardized and recognized by all major SCADA providers. Many of these protocols now contain extensions for working through TCP / IP. Although the use of conventional network specifications, such as TCP / IP, blur the line between traditional and industrial networks, each of them implements fundamentally different requirements. Network simulation can be used in conjunction with SCADA simulators to perform various analyzes.
SCADA at the present stage
With increasing security requirements, satellite communications are increasingly being used. This has key advantages in that the infrastructure can be autonomous (without using schemes from a public telephone system), it can have built-in encryption and can be designed taking into account the availability and reliability required by the SCADA system operator. Earlier experiments using the consumer class were unsatisfactory. Modern carrier-class systems provide the quality of service required by SCADA.
Security issues
SCADA systems that integrate decentralized facilities such as energy, oil, gas pipelines, water distribution and wastewater collection systems have been designed to be open, reliable and easily manageable. The transition from proprietary technologies to more standardized and open solutions along with an increase in the number of connections between SCADA systems, office networks and the Internet has made them more vulnerable to the types of network attacks that are relatively common in computer security. A vulnerability alert was issued that contained information that unauthenticated users could download confidential configuration information, including password hashes, from an inductive auto-ignition system using a standard attack type that provided access to Tomcat Embedded. Thus, the security of some SCADA-based systems has been called into question, since they were considered as potentially vulnerable to cyber attacks.
Troubleshooting options
The increased interest in SCADA vulnerabilities has led researchers to discover problems in the commercial design of SCADA systems and more general offensive techniques presented to the general security community. In SCADA systems with electric and gas utilities, the vulnerability of a large installed base of wired and wireless serial communication channels is eliminated in some cases by using devices with spikes in a wired network that use authentication and advanced encryption encryption, rather than replacing all existing nodes.
First vulnerability
In June 2010, VirusBlokAda anti-virus protection announced the first detection of malware that attacks SCADA systems (Siemens WinCC / PCS 7 systems) running on Windows operating systems. The malware is called Stuxnet and uses four zero-day attacks to install a rootkit, which in turn enters the SCADA database and steals design and management files. A malicious program can also modify the control system and hide these changes. In October 2013, National Geographic released documentation called American Blackout, which examined the widespread cyber attack on SCADA and the United States power grid.
The risks
SCADA systems are used to control and monitor physical processes, examples of which are power transmission, transport of oil and gas products, water distribution, traffic lights and other systems used as the basis of modern society. The safe mode of operation of these SCADA systems is very important, since compromise or their destruction will affect many areas of society that are far from the initial compromise. For example, the blackout caused by a compromised SCADA electrical system will result in financial losses for all customers who receive electricity from this source.