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What is the priority triad used in OT/ICS security, and how does it differ from the IT CIA triad?

CIA — Confidentiality, Integrity, Availability (same as IT)

AIC — Availability, Integrity, Confidentiality (reordered IT triad)

SIA — Safety, Integrity, Availability (safety is the top priority)

ASR — Availability, Speed, Reliability

to track

2026 Statistics

Key Facts: ICS/SCADA Exam

Exam Questions

EC-Council

70%

Passing Score

EC-Council

2 hours

Exam Duration

EC-Council

$450

Exam Fee

EC-Council

Content Modules

EC-Council ICS/SCADA

3 years

Certification Validity

ECE required

The EC-Council ICS/SCADA exam has 75 multiple-choice questions in 2 hours with a 70% passing score. It covers IT vs OT security, ICS components, industrial protocols, ICS threats, network segmentation via the Purdue Model, IEC 62443, NIST 800-82r3, OT monitoring, and risk management. The exam emphasizes the Safety-Integrity-Availability priority order unique to OT environments.

Sample ICS/SCADA Practice Questions

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1What is the priority triad used in OT/ICS security, and how does it differ from the IT CIA triad?

A.CIA — Confidentiality, Integrity, Availability (same as IT)

B.AIC — Availability, Integrity, Confidentiality (reordered IT triad)

C.SIA — Safety, Integrity, Availability (safety is the top priority)

D.ASR — Availability, Speed, Reliability

Explanation: OT/ICS environments use the SIA triad — Safety, Integrity, Availability — because industrial systems control physical processes where loss of safety can injure people or damage equipment. This contrasts with IT's CIA triad, where Confidentiality is paramount. In OT, confidentiality is typically the lowest priority because the focus is on keeping the plant running safely without interruption.

2Which of the following is the most important reason patching is more difficult in OT environments than in IT?

A.OT vendors do not release patches

B.Production downtime to apply patches is often unacceptable and patches must be vendor-validated

C.OT systems are immune to vulnerabilities

D.Only the vendor is allowed to install patches by law

Explanation: In OT environments, planned downtime windows are rare (sometimes only once per year or less) and unscheduled outages can halt production lines, endanger safety, or violate availability SLAs. Patches must also be validated by the vendor against the specific automation system because changes can break process logic. This is why compensating controls and segmentation are emphasized over rapid patching.

3Which lifecycle duration is most typical for industrial control system equipment compared with enterprise IT equipment?

A.1-2 years for ICS, similar to laptops

B.3-5 years for ICS, similar to servers

C.15-30 years for ICS, much longer than IT

D.ICS equipment is replaced annually

Explanation: ICS equipment such as PLCs, RTUs, and DCS controllers commonly remains in service for 15 to 30 years or more, compared to IT hardware that is typically refreshed every 3 to 5 years. This long lifecycle means many production systems still run obsolete operating systems, legacy protocols, and components that were never designed with modern cybersecurity in mind.

4Which OT operational requirement is the primary reason that traditional IT antivirus scanning is often disabled or restricted on engineering workstations and HMI servers?

A.Antivirus software is illegal in OT

B.Real-time control loops cannot tolerate scan-induced CPU spikes or false positives

C.OT systems do not get malware

D.Antivirus is only needed on email servers

Explanation: OT systems run deterministic real-time processes; an antivirus scan that consumes CPU at the wrong moment can cause control loop delays, dropped messages, or false-positive quarantines that remove a legitimate driver or process. For these reasons, OT vendors often supply approved AV configurations with scheduled scans, exclusions for project files, and update freezes during production.

5In an OT environment, which event is generally considered the WORST possible outcome of a cybersecurity incident?

A.Loss of data confidentiality

B.Brief degradation of plant performance

C.Loss of safety leading to injury, death, or environmental damage

D.An auditor finding a missing log

Explanation: In OT, the worst outcome is loss of safety — physical harm to people, environmental damage, or destruction of equipment. This is why Safety leads the SIA triad. Confidentiality breaches and audit findings are unwelcome but recoverable, while a process safety incident can be irreversible.

6Which statement best describes why deterministic communication is critical in OT networks but generally not in IT networks?

A.OT data is more confidential than IT data

B.Control loops must execute within strict, predictable time windows or process stability is lost

C.Determinism makes web browsing faster

D.IT networks are slower than OT networks

Explanation: Industrial control loops sample sensors, compute outputs, and actuate every few milliseconds. Variable latency or jitter can destabilize control, cause oscillation, or trip safety systems. Determinism — predictable timing — is therefore a hard requirement for many ICS protocols, while IT applications such as email tolerate variable latency.

7Which of the following BEST describes a Safety Instrumented System (SIS)?

A.A database that stores process history

B.A system separate from the basic process control system that automatically takes the process to a safe state when defined limits are exceeded

C.A type of HMI graphical display

D.A backup HMI used by operators

Explanation: A Safety Instrumented System (SIS) is an independent layer of protection that monitors process variables and, when safe limits are violated, automatically drives the process to a safe state — for example by closing a valve or de-energizing a pump. SIS is governed by IEC 61508/61511 and must be independent from the Basic Process Control System (BPCS). The Triconex SIS was the target of the TRITON attack.

8Which statement about typical OT change management is most accurate?

A.Changes are pushed daily by automated patch management systems

B.Changes follow rigorous Management of Change (MOC) processes with engineering approval and risk reviews

C.Changes do not need approval if the vendor recommends them

D.Changes are not tracked because OT is air-gapped

Explanation: OT environments use formal Management of Change (MOC) procedures. Any change to control logic, network configuration, or hardware undergoes engineering review, hazard analysis, and approval before deployment, typically during a planned outage. This conservatism reflects the safety and availability priorities that dominate OT.

9Which of the following is the BEST example of a 'cyber-physical' consequence unique to OT incidents?

A.An employee's email is read by an attacker

B.A web server is defaced

C.Centrifuges spin out of tolerance and physically break

D.A document is accidentally deleted

Explanation: Cyber-physical impact means that a digital attack causes physical damage to equipment, processes, or people. The Stuxnet worm famously caused physical destruction of uranium enrichment centrifuges by manipulating their PLC speed setpoints. Email reads and website defacement are pure cyber consequences with no physical manifestation.

10Which of the following is the strongest argument AGAINST treating an OT network exactly like an IT network?

A.OT uses the same TCP/IP stack as IT, so no special handling is needed

B.OT availability tolerances, real-time requirements, legacy protocols, and safety implications differ fundamentally from IT

C.OT does not have any cybersecurity needs

D.IT networks have higher security requirements than OT

Explanation: OT networks have unique constraints: availability budgets measured in minutes per year, sub-second control loops, decades-old equipment, plaintext protocols like Modbus, and direct safety implications. Imposing IT controls — frequent patching, active vulnerability scanning, automatic reboots — without adaptation can cause production outages or safety incidents.

About the ICS/SCADA Exam

The EC-Council ICS/SCADA Cybersecurity certification validates skills in securing industrial control systems and SCADA environments. The exam covers IT vs OT priorities, ICS components (PLCs, RTUs, HMIs), industrial protocols (Modbus, DNP3, IEC 61850, OPC UA), the Purdue Reference Model, ICS threats including Stuxnet and TRITON, IEC 62443 zones-and-conduits, NIST SP 800-82r3, NERC CIP, and OT-specific monitoring and risk management.

Questions

75 scored questions

Time Limit

2 hours

Passing Score

70%

Exam Fee

$450 (exam voucher) (EC-Council Exam Portal)

ICS/SCADA Exam Content Outline

13%

IT Security vs OT/ICS

IT vs OT priorities, CIA vs SIA (Safety, Integrity, Availability), operational constraints, real-time requirements, and lifecycle differences

12%

ICS Components

PLCs, RTUs, HMIs, historians, IEDs, engineering workstations, SCADA master/server architecture, and DCS controllers

13%

ICS Network Protocols

Modbus TCP/RTU function codes, DNP3 outstation/master, IEC 61850 GOOSE/SV, OPC UA security model, EtherNet/IP, BACnet, and PROFINET

12%

ICS Threats and Attacks

Stuxnet (Siemens S7), Industroyer/CRASHOVERRIDE, TRITON/TRISIS (Triconex SIS), BlackEnergy, Havex, and Pipedream/INCONTROLLER

14%

Securing the ICS Network

Network segmentation, Purdue Reference Model levels 0-5, industrial DMZ, data diodes, unidirectional gateways, and jump hosts

13%

ICS Standards and Frameworks

NIST SP 800-82r3, IEC/ISA 62443 zones-and-conduits, security levels SL-T 1-4, NERC CIP-002 to CIP-014, and NIS2 directive

12%

IDS/IPS and Monitoring

Passive monitoring with Claroty, Dragos, Nozomi Networks, ICS-aware Snort/Suricata rules, asset discovery, and anomaly detection

11%

ICS Risk Management

OT risk assessment, BCP/DR for industrial systems, patch management challenges, vendor management, and supply chain security

How to Pass the ICS/SCADA Exam

What You Need to Know

Passing score: 70%
Exam length: 75 questions
Time limit: 2 hours
Exam fee: $450 (exam voucher)

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

ICS/SCADA Study Tips from Top Performers

1Memorize the OT priority triad SIA (Safety, Integrity, Availability) and how it differs from IT's CIA triad

2Master the Purdue Reference Model levels 0-5 and the role of Level 3.5 industrial DMZ

3Learn Modbus function codes (01 read coils, 03 read holding registers, 05 write single coil, 06 write single register, 15/16 multiple)

4Understand DNP3 outstation/master roles and the difference between unsolicited responses and polling

5Study IEC 61850 substation messages: GOOSE for protection signaling, SV for sampled values, MMS for client/server

6Know IEC 62443 zones-and-conduits, security levels SL 1-4 (casual to nation-state), and the asset owner/integrator/product supplier roles

7Memorize the famous ICS attacks: Stuxnet (Siemens S7), TRITON (Triconex SIS), Industroyer (IEC 101/104, 61850, OPC), BlackEnergy, Havex, Pipedream

8Understand why data diodes and unidirectional gateways are preferred over firewalls for one-way Level 3 to Level 4 historian replication

Frequently Asked Questions

What is the EC-Council ICS/SCADA exam format?

The EC-Council ICS/SCADA Cybersecurity exam consists of 75 multiple-choice questions to be completed in 2 hours, with a 70% passing score. Questions cover IT vs OT security differences, ICS components, industrial protocols, the Purdue Model, IEC 62443, NIST SP 800-82r3, ICS threats, and OT risk management.

How does ICS/SCADA security differ from traditional IT security?

OT/ICS security prioritizes Safety, Integrity, and Availability (SIA) rather than the traditional IT triad of Confidentiality, Integrity, and Availability (CIA). OT systems have decade-long lifecycles, real-time requirements, and tolerate almost no downtime, so patching is rare and confidentiality is often the lowest priority compared to keeping people and equipment safe.

What is the Purdue Reference Model?

The Purdue Reference Model is a hierarchical framework for ICS network segmentation defining Level 0 (physical process), Level 1 (basic control PLCs/RTUs), Level 2 (supervisory HMIs), Level 3 (operations management), Level 3.5 (industrial DMZ), Level 4 (enterprise), and Level 5 (internet). It is a foundational concept on the EC-Council ICS/SCADA exam.

What ICS attacks are covered on the exam?

Key ICS attacks tested include Stuxnet (2010, targeted Siemens S7 PLCs), Industroyer/CRASHOVERRIDE (2016, Ukrainian power grid), TRITON/TRISIS (2017, Triconex Safety Instrumented Systems), BlackEnergy (2015, Ukrainian utilities), Havex (energy sector espionage), and Pipedream/INCONTROLLER (2022, modular ICS attack toolkit).

What jobs can I get with EC-Council ICS/SCADA certification?

The certification prepares you for OT/ICS Cybersecurity Engineer, SCADA Security Analyst, Industrial Cybersecurity Consultant, Critical Infrastructure Protection (CIP) Specialist, NERC CIP Compliance Analyst, Operational Technology Security Architect, and Plant Cybersecurity Manager roles in energy, manufacturing, water, and critical infrastructure sectors.