Nexus SecOps Reference Architecture¶

This document defines the reference architecture for an AI-Powered Security Operations Center. It describes the technology layers, their relationships, and design principles that underpin the Nexus SecOps benchmark.

Architecture Overview¶

flowchart TD
    subgraph SOURCES["Log Sources"]
        EP[Endpoints\nEDR / AV]
        NET[Network\nFirewall / NDR / DNS]
        ID[Identity\nIdP / AD / SSO]
        CLD[Cloud\nAWS / Azure / GCP]
        APP[Applications\nWeb / API / Email]
        OT[OT/ICS\nSensors via Diode]
    end

    subgraph COLLECT["Collection Layer"]
        AGT[Agents\n& Forwarders]
        API[API Collectors\n& Connectors]
        SYS[Syslog Receivers]
        BUF[Message Buffer\nKafka / Queue]
    end

    subgraph STORE["Storage and Processing"]
        SIEM[SIEM\nRule Engine + Correlation]
        DL[Data Lake\nLong-term + ML]
        HOT[Hot Storage\n0-90 days]
        WARM[Warm Storage\n90d-1yr]
        COLD[Cold Archive\n1yr+]
    end

    subgraph INTEL["Intelligence Layer"]
        TIP[Threat Intel\nPlatform]
        FEEDS[External Feeds\nISAC / OSINT]
        ENRICH[Enrichment\nGeo / ASN / CMDB]
    end

    subgraph DETECT["Detection Layer"]
        RULES[Rule Engine\nSigma / Native]
        ML[ML Models\nUEBA / Anomaly]
        CORR[Correlation\nMulti-event]
    end

    subgraph AUTO["Automation Layer"]
        SOAR[SOAR Platform]
        PB[Playbooks]
        GATE[Human Gates\nApproval Workflow]
    end

    subgraph PRESENT["Presentation Layer"]
        CASE[Case Management]
        DASH[SOC Dashboard]
        RPT[Reporting]
    end

    subgraph AI["AI Assistance Layer"]
        LLM[LLM Copilot]
        RAG[RAG Knowledge Base\nRunbooks / TI / History]
    end

    SOURCES --> COLLECT
    COLLECT --> BUF
    BUF --> STORE
    FEEDS --> TIP
    TIP --> INTEL
    ENRICH --> INTEL
    INTEL --> DETECT
    STORE --> DETECT
    DETECT --> AUTO
    AUTO --> PRESENT
    INTEL -.->|Contextual enrichment| PRESENT
    RAG --> LLM
    LLM -.->|Analyst assistance| PRESENT

Layer Descriptions¶

Collection Layer¶

Purpose: Reliably transport log data from sources to the storage and processing layer with minimal loss and latency.

Components:

Design principles: - Encrypt all transport (TLS 1.2+) — Nexus SecOps-003 - Buffer to prevent data loss during SIEM maintenance — Nexus SecOps-002 - Monitor delivery health; alert on gaps — Nexus SecOps-007 - Deploy agents at ≥98% coverage for managed endpoints — Nexus SecOps-006

Storage Layer¶

Purpose: Retain security logs in queryable form for detection and investigation, and in archived form for compliance.

Tiered Storage Model:

SIEM vs. Data Lake:

Intelligence Layer¶

Purpose: Enrich security events with contextual data that transforms raw logs into actionable intelligence.

Enrichment types:

Nexus SecOps controls: Nexus SecOps-018 (asset enrichment), Nexus SecOps-019 (IP enrichment), Nexus SecOps-026 (TI enrichment), Nexus SecOps-081–095 (CTI domain)

Detection Layer¶

Purpose: Identify threat behavior in log data through rules, correlation, and machine learning.

Detection engine types:

Detection content governance: All rules MUST follow the detection change control process (Nexus SecOps-033, Nexus SecOps-203). Rules are version-controlled in a git repository.

Automation Layer¶

Purpose: Accelerate response actions, reduce manual workload, and enforce consistent processes through SOAR playbooks.

Key design principles: - All high-impact actions (account disable, host isolation) MUST have human approval gates — Nexus SecOps-099 - Playbooks MUST be version-controlled and tested before deployment — Nexus SecOps-098, 100 - All automation actions MUST be logged with full audit trail — Nexus SecOps-102 - Rollback procedures MUST exist for all automated actions — Nexus SecOps-103

Automation tiers:

Presentation Layer¶

Purpose: Surface actionable intelligence to analysts in the right format at the right time.

Components:

AI Assistance Layer¶

Purpose: Augment analyst productivity through LLM-powered copilots grounded in authoritative security knowledge.

Architecture:

flowchart LR
    Q[Analyst Query] --> EMB[Query Embedding]
    EMB --> VS[Vector Search]
    VS --> KB[(Knowledge Base\nRunbooks / TI Reports\nPlaybooks / History)]
    KB --> CTX[Retrieved Context]
    CTX --> PROMPT[Augmented Prompt]
    Q --> PROMPT
    PROMPT --> LLM[LLM API]
    LLM --> OUT[Response + Citations]
    OUT --> ANALYST[Analyst Review]

Key requirements: - All LLM deployments inventoried — Nexus SecOps-181 - Prompt injection defense implemented — Nexus SecOps-182 - RAG grounding for factual queries — Nexus SecOps-184 - PII filtered before external API submission — Nexus SecOps-186 - Human review required before acting on LLM output — Nexus SecOps-191

High Availability Design¶

Single points of failure to eliminate:

Security of the SOC Infrastructure¶

The SOC tools themselves are high-value targets. Apply these controls:

Technology Selection Criteria¶

See Data Pipeline Patterns | Integration Patterns | Zero Trust SOC Nexus SecOps controls: All 14 domains apply to this architecture.