Individual skill
detecting-modbus-protocol-anomalies
Detect anomalies in Modbus/TCP and Modbus RTU industrial traffic via function code monitoring, register range validation, timing analysis, and deep packet inspection, using Zeek's Modbus analyzer, Suricata IDS with OT rules, and Python Markov chain models of normal transaction sequences. Use for deploying Modbus IDS in OT environments, baselining polling patterns, investigating suspicious Modbus traffic, or building function code allowlists.
skills/detecting-modbus-protocol-anomalies/SKILL.md
Source commit 54a798831d2266a3ca61ce68a7acb80b81160d57
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- Last checked
- Nov 9, 2026
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- 35,897
- Repository last updated
- Aug 31, 2026
- License
- Apache-2.0
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- ai-agents Repository topic
- claude-code Repository topic
- cybersecurity Repository topic
- incident-response Repository topic
- mitre-attack Repository topic
- penetration-testing Repository topic
- red-team Repository topic
- security Repository topic
- cloud-security Repository topic
- malware-analysis Repository topic
- ot-security Declared skill tag
- ics Declared skill tag
- scada Declared skill tag
- industrial-control Declared skill tag
- iec62443 Declared skill tag
- modbus Declared skill tag
- protocol-anomaly Declared skill tag
- security Derived category
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LICENSEasset · 11,255 bytesSKILL.mdcore · 14,940 bytesSKILL.mdcore · 14,940 bytesSKILL.mdcore · 14,940 bytesSKILL.mdcore · 14,940 bytesreferences/api-reference.mddoc · 1,662 bytesscripts/agent.pyruns · 5,512 bytes
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# Detecting Modbus Protocol Anomalies
## When to Use
- When deploying Modbus-specific intrusion detection in an OT environment
- When building baseline models for deterministic Modbus polling patterns
- When investigating suspicious Modbus traffic flagged by OT monitoring tools
- When implementing function code allowlisting on industrial firewalls
- When detecting unauthorized Modbus write commands that could manipulate process setpoints
**Do not use** for securing Modbus communications end-to-end (Modbus has no native security; see implementing-network-segmentation-for-ot for firewall-based controls), for non-Modbus protocol monitoring (see detecting-anomalies-in-industrial-control-systems for multi-protocol), or for active fuzzing of Modbus implementations (see performing-plc-firmware-security-analysis).
## Prerequisites
