CyTReX: Explainable AI-Based Cybersecurity Threat Reasoning Framework for DER Networks
Organizations: Department of Electrical and Computer Engineering Iowa State University, Ames, IA 50011
Abstract
Distributed Energy Resource (DER) environments rely on network communication protocols to coordinate control commands, measurements, and device states across edge assets and cloud systems. Edge anomaly detection systems (ADS) monitor this traffic to identify deviations from normal communication behavior, flagging suspicious flows for further investigation. When the ADS flags abnormal network traffic, a single attack label is often insufficient for operational response: the label reports the detector's selected class but does not expose alternative threat interpretations that may warrant investigation. This paper presents Cybersecurity Threat Reasoning with Explainable Artificial Intelligence (CyTReX), an evidence-grounded threat reasoning framework for DER security that transforms network-level anomaly alerts into ranked, analyst-facing threat hypotheses designed to support Security Operations Center (SOC) triage and investigation. CyTReX constrains large language model (LLM) reasoning through a structured evidence packet, defined as a consolidated record of detection outputs, model explanations, and cyber threat intelligence (CTI) context. The evidence packet integrates edge-layer anomaly detection evidence, cloud reasoning layer attack interpretation, Shapley Additive Explanations (SHAP) network-feature attributions, surrogate decision rules, and Model Context Protocol (MCP)-enabled CTI enrichment. This ensures that every ranked hypothesis and attack-tree branch is traceable to explicit evidence rather than free-form LLM inference, and that incomplete or conflicting evidence is communicated rather than suppressed. Evaluation across five configurations shows that additional reasoning components improve hypothesis specificity, evidence traceability, and analytical grounding, with the complete pipeline providing the richest evidence-grounded reasoning context.
Figures & tables
| Framework / Approach | ML Anomaly Detection | Explainable AI (XAI) | CTI Enrichment | LLM-Assisted Reasoning | Ranked Hypotheses | Grid/Industrial Control Systems (ICS) Focus |
|---|---|---|---|---|---|---|
| ML-Based Anomaly Detection System (ML-ADS) [ 3 ] | ||||||
| CySIDER [ 15 ] | ||||||
| XAI-Forensic Intrusion Detection System (IDS) [ 5 ] | ||||||
| ExCyDER [ 16 ] | ||||||
| LLM Cybersecurity Survey [ 17 ] | ||||||
| SEvenLLM [ 18 ] |
| Label | Use in this study | Meaning in DNP3 context |
|---|---|---|
| NORMAL | Benign baseline | Expected DNP3 communication behavior. |
| REPLAY | Trained attack | Replay of DNP3 packets previously captured from a legitimate DNP3 master or outstation. |
| COLD_RESTART | Trained attack | A malicious master-like entity sends the DNP3 cold-restart function code, causing the target outstation to initiate a complete restart. |
| WARM_RESTART | Trained attack | A malicious master-like entity sends the DNP3 warm-restart function code, causing a partial restart or reinitialization of the DNP3 service. |
| STOP_APP | Trained attack | A stop-application command associated with DNP3 Function Code 18 asks the slave/outstation to stop a function so it cannot continue receiving messages from the master. |
| DISABLE_UNSOLICITED | Trained attack | A command associated with DNP3 Function Code 21 disables unsolicited messages from the target outstation. |
| Tool | Purpose |
|---|---|
| extract_evidence_terms | Extracts CTI query terms from edge, cloud, SHAP, rule, and flow evidence. |
| query_mitre_attack_ics | Retrieves MITRE ATT&CK for ICS techniques, tactics, STIX relationships, and official mitigations. |
| query_capec_patterns | Retrieves CAPEC attack-pattern context from the CAPEC Extensible Markup Language (XML) corpus. |
| retrieve_full_cti_context | Orchestrates evidence-term extraction, MITRE retrieval, CAPEC retrieval, normalization, and provenance recording. |
| Config. | Configuration | Purpose |
|---|---|---|
| C1 | Edge-only: Edge evidence + LLM | Tests whether edge anomaly evidence alone supports attack-tree generation. |
| C2 | Edge-only: Edge evidence + CTI + LLM | Tests whether CTI enriches edge-only reasoning without cloud reasoning layer attack interpretation. |
| C3 | Full pipeline: Edge evidence + cloud reasoning layer attack interpretation + LLM | Tests the effect of cloud reasoning layer attack interpretation. |
| C4 | Full pipeline: Edge evidence + cloud reasoning layer attack interpretation + Rule-SHAP + LLM | Tests whether model explanation features improves evidence support. |
| C5 | Complete pipeline: Edge evidence + cloud + Rule-SHAP + CTI + LLM | Tests the complete evidence-grounded reasoning workflow. |
| Attack label | Result | C1 | C2 | C3 | C4 | C5 |
|---|---|---|---|---|---|---|
| COLD_RESTART | H1 | DNP3 replay | Rogue master | Cold restart | Cold restart | Denial of service |
| Latency | 152.06 s | 180.74 s | 138.85 s | 117.95 s | 160.33 s | |
| DISABLE_UNSOLICITED | H1 | Command replay | Distributed denial-of-service (DDoS) attack | Disable unsolicited | Cold restart | DNP3 replay |
| Latency | 135.82 s | 182.78 s | 122.78 s | 151.20 s | 134.18 s | |
| INIT_DATA | H1 | Rogue master | Denial of service | Rogue master | Cold restart | DNP3 replay |
| Latency | 150.28 s | 157.64 s | 142.43 s | 176.39 s | 133.37 s |
| Layer | Model | Acc. | Prec. | Rec. | F1 |
|---|---|---|---|---|---|
| Edge | Isolation Forest+Nearest Neighbor | 98.43 | 99.04 | 99.37 | 99.21 |
| Edge | Isolation Forest | 97.93 | 98.98 | 98.85 | 98.91 |
| Edge | Extended Isolation Forest | 57.52 | 98.50 | 56.26 | 71.61 |
| Cloud | LightGBM | 99.58 | 99.58 | 99.58 | 99.58 |
| Cloud | Extreme Gradient Boosting (XGBoost) | 99.08 | 99.10 | 99.08 | 99.08 |
| Cloud | Random Forest | 85.79 | 88.31 | 85.80 | 85.32 |
| OOD label | Result | C2 | C5 |
|---|---|---|---|
| DNP3_ENUM | H1 | Parameter manipulation | DNP3 replay |
| H2 | Data collection | Denial of service | |
| H3 | Process disruption | Rogue master injection | |
| Latency | 153.00 s | 136.15 s | |
| DNP3_INFO | H1 | Parameter manipulation | DNP3 replay |
| H2 | Initial access attempt | DNP3 spoofing |
Cybersecurity
Cybersecurity develops methods to protect digital and cyber-physical systems from attacks, vulnerabilities, data loss, and misuse.
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