OT and ICS Security Testing
That Puts Safety First
Industrial control systems were built for reliability, not for a connected world. We assess your plant networks, remote access and control systems with passive, low-impact methods first, so you see the real risks without putting operations at risk.
OT security testing
Find the Paths From IT to Your Control Systems Before Attackers Do
Attacks on industrial environments often start in the corporate network or through a remote access connection. We trace those paths, review how well your OT zones are separated and test control systems in a way your operations team agrees with, aligned to ISA/IEC 62443 and NIST SP 800-82.
100%
Findings manually validated by a tester
6
Phase, standards-aligned methodology
40+
Enterprise and government clients
15+
Countries served
Why iSpyCyber
Why Organisations Choose iSpyCyber for OT Security
In a plant, a security test must never become the incident. Our approach is built around that rule.
Safety first
Passive analysis comes first. Any active test is agreed with your operations team, run in a maintenance window or on test equipment, and stopped at once if anything looks wrong.
IT and OT in one team
The same team tests your corporate network and your plant network, so attack paths that cross the boundary between them are followed end to end.
Standards aligned
Findings are mapped to ISA/IEC 62443 zones, conduits and security levels, and to MITRE ATT&CK for ICS techniques.
Practical fixes
Recommendations respect plant realities, such as systems that cannot be patched, with compensating controls where a direct fix is not possible.
Clear for engineers and leaders
Plant engineers get the technical detail, and leadership gets the risk explained in terms of safety, downtime and compliance.
Proof of improvement
We retest fixed findings and can repeat the assessment over time to show how your OT security is improving.
Coverage
What We Assess in Your OT Environment
From the boundary with your corporate network down to controllers and field networks, we look at every path an attacker could use to reach the process.
IT/OT boundary and segmentation
Firewalls, DMZs and conduits between corporate and plant networks, reviewed against the Purdue model and ISA/IEC 62443 zones.
Remote access
Vendor VPNs, jump hosts, remote desktop tools and cellular modems that could give an attacker a way into the plant.
Asset inventory and traffic
Passive capture of network traffic to identify assets, communication paths and unexpected connections.
HMIs and engineering workstations
Hardening, patch levels, user accounts and the software used to program and change controllers.
PLCs, RTUs and controllers
Configuration, firmware versions, access controls and exposure of programming interfaces, tested on test equipment or with agreement.
Industrial protocols
Use of Modbus, DNP3, S7, EtherNet/IP, OPC UA and IEC 60870-5-104, and whether commands could be sent without authentication.
Wireless and field networks
Industrial Wi-Fi, radio links and wireless sensor networks that extend the plant network beyond its perimeter.
Historians and data flows
Historians, data diodes and integrations that move plant data into business and cloud systems.
Backup and recovery
Whether controller logic, configurations and system images are backed up, protected and recoverable after an incident.
Methodology
A Six-Phase, Safety-First Methodology
Aligned to ISA/IEC 62443 and NIST SP 800-82, with attacker techniques mapped to MITRE ATT&CK for ICS.
Phase 01
Scope and safety plan
We agree the sites, zones and systems in scope, the test windows and the safety rules with your operations team.
Output: Approved test and safety plan
Phase 02
Architecture review
Review of network diagrams, firewall rules, asset lists and remote access arrangements.
Output: Zone and conduit model
Phase 03
Passive assessment
Traffic captured from network taps or mirror ports to map assets and communication without touching control systems.
Output: Asset and traffic analysis
Phase 04
Controlled testing
Carefully limited active checks, run in a maintenance window, on test equipment or on a replica, as agreed.
Output: Validated findings
Phase 05
Report and debrief
Risk-rated findings with evidence and practical fixes, walked through with engineering, security and leadership.
Output: Report and debrief session
Phase 06
Fix and retest
We retest remediated findings and confirm which issues have been closed.
Output: Retest report
Engagement models
Choose the Assessment That Fits Your Plant
Start with a zero-impact architecture review, add passive analysis, or validate real exploitability under controlled conditions.
Architecture and segmentation review
A desk-based review of diagrams, firewall rules and remote access, with interviews of your engineers.
Best for: A first look at OT risk with no impact on operations
Passive OT assessment
An architecture review plus passive traffic analysis on site or from network captures you provide.
Best for: Live plants where systems cannot be touched
Controlled active testing
A passive assessment plus agreed active tests on test equipment, a replica or in a maintenance window.
Best for: Validating exploitability and new systems before go-live
Not sure which approach you need?
Tell us about your environment and we will recommend the right scope.
Deliverables
Reports Built for Leadership, Engineering and Auditors
Executive summary
OT risk explained in terms of safety, downtime and compliance, with an overall rating for leadership.
Technical findings
Each finding with affected assets, evidence, a risk rating and remediation or compensating controls.
Remediation roadmap
Fixes prioritised by risk and by what is practical in your plant, from quick wins to work planned around maintenance cycles.
Retest report
Confirmation of which findings are closed, for your records, auditors and regulators.
Standards
Supports Your Compliance and Assurance Requirements
- ISA/IEC 62443
- NIST SP 800-82
- MITRE ATT&CK for ICS
- NIST CSF 2.0
- ISO/IEC 27001
- ISO/IEC 27019
- NCIIPC guidelines
- CERT-In guidelines
iSpyCyber provides testing and evidence that support these requirements. Certification and attestation are issued by accredited bodies and auditors.
FAQ
OT security testing questions, answered
The basics
What is OT security testing?
It is an assessment of the networks and systems that monitor and control physical processes, such as PLCs, SCADA, HMIs and engineering workstations. It finds the weaknesses an attacker could use to disrupt operations and shows how to reduce the risk safely.
Which standards do you follow?
We align our work to ISA/IEC 62443 and NIST SP 800-82, and map attacker techniques to MITRE ATT&CK for ICS.
Which systems can you assess?
PLCs, RTUs, DCS and SCADA systems, HMIs, engineering workstations, historians and the networks between them. We assess systems by how they work and communicate, whichever vendor supplied them.
Working with us
Will testing disrupt our operations?
Our default approach is passive and does not send traffic to control systems. Any active test is agreed in advance, run in a maintenance window, on test equipment or on a replica, and stopped immediately if your operations team asks.
Do you need to visit our site?
Often, yes, to capture traffic and see the plant network as it really is. Architecture reviews and some analysis can be done remotely from diagrams, configurations and traffic captures you provide.
How long does an OT assessment take?
It depends on the number of sites and zones and whether site visits are needed. We confirm the timeline in our proposal after a scoping call.
Do you retest after we fix the issues?
Yes. We retest remediated findings and issue an updated report. Where a fix is not possible, we help you confirm that compensating controls are working.
Still have a question? Talk to our security team.