This guide covers the top open-source OT cybersecurity tools used by industrial security teams, including Suricata, Zeek, Wazuh, Malcolm, Cuckoo Sandbox, and Volatility.
Operational Technology (OT) cybersecurity teams are under increasing pressure. Legacy industrial protocols offer little native visibility, threat activity continues to rise, and security teams are expected to do more with fewer resources.
To close these gaps, many industrial defenders are turning to open-source security tools. When deployed correctly, these tools provide deep visibility, strong detection capabilities, and forensic insight—often rivaling expensive commercial platforms.
In this post, we break down six of the most impactful open-source tools shaping OT cybersecurity, including where each shines, where they fall short, and how they’re commonly operationalized in modern industrial environments. We’ll also show how these tools fit into hybrid approaches like Valkyrie, which wraps open-source engines with production-grade reliability and support.
1. Suricata: High-Performance Intrusion Detection for Industrial Networks
Primary role: Network intrusion detection and prevention (IDS/IPS)
Suricata is a high-performance network threat detection engine widely used for deep packet inspection and rule-based detection. In OT environments, its ability to inspect industrial protocols like Modbus, DNP3, and S7 makes it a cornerstone of network-based defense.
Why it matters in OT
Industrial networks can no longer rely on “air gaps.” Suricata enables OT teams to detect:
- Unauthorized control commands
- Known ICS malware signatures
- Lateral movement between IT and OT zones
Common OT use cases
- Monitoring substation or plant-floor network segments
- Detecting anomalous PLC communications
- Feeding alerts into SIEM or SOC workflows
Strengths
- Enterprise-grade detection with no license cost
- Multi-threaded and high-throughput
- Custom rule creation for proprietary or legacy protocols
- Strong integration with SIEMs and log platforms
Limitations
Requires significant tuning to reduce false positives
Limited native support for vendor-specific protocols
Ongoing rule maintenance can overwhelm small teams
How Valkyrie fits
Valkyrie runs Suricata with continuously maintained rules, protocol updates, and expert tuning, removing the operational burden while preserving detection fidelity.
2. Zeek: Deep Network Visibility and Behavioral Detection
Primary role: Network metadata logging and anomaly detection
Zeek (formerly Bro) focuses on what’s happening on the wire, not just whether traffic matches known signatures. It logs detailed protocol activity and behavioral metadata—an essential capability in OT environments where endpoint logging is sparse.
Why it matters in OT
Zeek provides visibility into:
- New or unauthorized devices
- Abnormal command sequences
- Policy violations across control networks
Common OT use cases
- Baseline “normal” industrial traffic
- Investigate incidents using historical network context
- Detect subtle anomalies missed by signature-based tools
Strengths
- Extremely detailed protocol and event logging
- Highly scriptable for custom detections
- Excellent for incident response and threat hunting
- Strong community and ecosystem
Limitations
- Not alert-centric by default
- Generates large volumes of data
- Requires skilled analysts to extract value
How Valkyrie fits
Valkyrie automatically correlates Zeek data with host and detection telemetry, transforming raw logs into actionable insights without manual log mining
3. Wazuh: Open-Source SIEM and Host Monitoring for OT
Primary role: Host-based intrusion detection, log correlation, SIEM/XDR
Wazuh combines endpoint monitoring, log aggregation, and correlation into a unified open-source platform. In OT environments, it’s often used as the backbone of a DIY industrial SOC.
Why it matters in OT
Wazuh helps OT teams:
- Monitor HMIs, engineering workstations, and servers
- Detect unauthorized changes or suspicious activity
- Correlate host and network events in one place
Common OT use cases
- Monitoring Windows-based OT assets
- Detecting malware, policy violations, or config drift
- Supporting compliance and audit requirements
Strengths
- Free, extensible SIEM capabilities
- Strong integration with Suricata and Zeek
- Built-in dashboards and reporting
- Large community and documentation
Limitations
- Complex to deploy and maintain
- Elastic backend requires care and tuning
- Agents may not be suitable for all OT systems
How Valkyrie fits
Valkyrie delivers Wazuh-like capabilities as a managed service, eliminating infrastructure maintenance while preserving unified visibility across OT environments.
4. Cuckoo Sandbox: Automated Malware Analysis for Industrial Incidents
Primary role: Dynamic malware analysis and detonation
Cuckoo Sandbox allows OT teams to safely analyze suspicious files in isolated environments—critical for industrial networks where cloud sandboxes may be inaccessible or inappropriate.
Why it matters in OT
OT malware is often:
- Highly targeted
- Environment-aware
- Designed to avoid traditional AV detection
Cuckoo reveals what malware actually does, not just what it looks like.
Common OT use cases
- Analyzing suspicious binaries found on HMIs or servers
- Investigating USB-borne threats
- Extracting indicators of compromise (IoCs)
Strengths
- Dynamic behavior analysis
- Highly customizable analysis environments
- Rich reports with process, file, and network artifacts
- Works in isolated OT networks
Limitations
- Sandbox-evasion techniques can reduce visibility
- Primarily supports traditional OS malware
- Requires maintenance and analyst interpretation
How Valkyrie fits
Valkyrie can automate malware detonation workflows, integrating sandbox results directly into detection and response pipelines, without manual overhead.
5. Volatility: Memory Forensics for Advanced OT Threats
Primary role: Memory analysis and incident forensics
Volatility is the gold standard for extracting forensic artifacts from RAM dumps—essential when dealing with fileless malware or in-memory attacks.
Why it matters in OT
Many advanced ICS attacks:
- Live only in memory
- Inject into legitimate processes
- Leave minimal disk artifacts
Volatility helps uncover what disk forensics cannot.
Common OT use cases
- Investigating compromised HMIs or engineering stations
- Analyzing suspected in-memory malware
- Performing root-cause analysis after incidents
Strengths
- Deep visibility into volatile system state
- Supports Windows, Linux, and macOS
- Extensive plugin ecosystem
- Zero impact on live systems
Limitations
- Requires high analyst skill
- Memory acquisition can be difficult in OT
- Time-intensive during active incidents
How Valkyrie fits
Valkyrie can orchestrate memory capture and analysis workflows, bringing Volatility-level insight into streamlined incident response without requiring standalone forensic tooling
6. Malcolm: Turnkey Network Traffic Analysis for OT and ICS Environments
Primary role: Integrated network traffic analysis, visibility, and threat detection platform
Malcolm is an open-source network traffic analysis framework originally developed to make powerful tools like Zeek and Suricata easier to deploy, operate, and visualize. Rather than being a single detection engine, Malcolm is best understood as a force multiplier—a packaged ecosystem that brings together packet capture, protocol analysis, intrusion detection, and dashboards into a deployable platform.
Why it matters in OT
OT security teams often struggle not with lack of tools, but with operational complexity. Running Zeek, Suricata, and packet capture at scale requires expertise, infrastructure, and constant care.
Malcolm lowers that barrier by:
- Providing out-of-the-box visibility into industrial network traffic
- Normalizing and indexing Zeek and Suricata outputs
- Making deep network telemetry usable for small or understaffed OT teams
In environments where deploying a full SOC stack is unrealistic, Malcolm enables rapid visibility without starting from scratch.
Common OT use cases
- Rapid deployment of network visibility in plants or substations
- Retrospective analysis of packet captures after incidents
- Supporting OT threat hunting and forensic investigations
- Gaining visibility into “unknown” or undocumented network behavior
Malcolm is frequently used by incident responders and security teams who need to drop in, collect traffic, and understand what’s happening fast—especially in brownfield OT environments.
Strengths
- Bundles Zeek, Suricata, PCAP ingestion, and dashboards
- Simplifies deployment with containerized architecture
- Excellent for traffic analysis, forensics, and investigations
- Strong community adoption in ICS and critical infrastructure
Malcolm is especially valuable for teams that want deep network insight without building a custom stack from scratch.
Limitations
- Not designed as a full SIEM or XDR platform
- Requires storage planning for PCAPs and logs
- Detection quality still depends on underlying tools and tuning
- Operational overhead increases at scale
Malcolm excels at visibility and analysis, but it does not inherently provide automated response, long-term correlation across hosts, or managed detection workflows.
How Valkyrie fits
Valkyrie addresses the same problem Malcolm was created to solve—but takes it further for production OT environments.
Where Malcolm packages open-source tools for easier deployment, Valkyrie:
- Continuously maintains and tunes detection engines
- Correlates network, host, and forensic data in real time
- Reduces analyst workload through automation and expert-driven updates
In practice, many of the capabilities Malcolm enables—Zeek visibility, Suricata detection, packet-level context—are natively operationalized inside Valkyrie, without requiring teams to manage containers, storage pipelines, or dashboards themselves
Conclusion: Open-Source Power, Without the Operational Burden
Open-source tools like Suricata, Zeek, Wazuh, Cuckoo, and Volatility have become indispensable in OT cybersecurity. They deliver transparency, flexibility, and deep technical capability—but they are not turnkey.
Standing up and maintaining an open-source OT security stack requires:
- Constant tuning
- Protocol expertise
- Infrastructure maintenance
- Dedicated analyst time
Hybrid platforms like Valkyrie bridge this gap by operationalizing proven open-source engines with enterprise reliability, expert tuning, and automation. The result is faster detection, fewer blind spots, and less operational drag for already-stretched OT teams.
For industrial organizations looking to modernize OT security without drowning in tooling overhead, the future is clear: open-source at the core, operationalized the right way.
Want to Go Deeper?
Open-source tools have become foundational to modern OT cybersecurity—but open source doesn’t mean free. Behind every “no-license” tool are real operational costs: staffing, tuning, maintenance, integration, and long-term reliability. Our white paper, Open Source Doesn’t Mean Free, takes a hard, practical look at what it really costs to run open-source security at scale in industrial environments. It breaks down where OT teams lose time and visibility, why many DIY stacks quietly fail, and how hybrid approaches can deliver open-source power without the operational drag. Download the white paper to understand the true cost equation—and how to get it right.
