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The Four CySA+ (CS0-003) Domains

The core knowledge areas of the CompTIA CySA+ (Cybersecurity Analyst, exam CS0-003). Each page below is written to the official CS0-003 exam objectives and covers the domain's concepts, Mermaid diagrams, and the key terms a sysadmin moving into a blue-team / SOC-analyst role needs — with a defensive framing throughout. The percentages are CompTIA's published weightings (the share of scored content per domain) (verify on CompTIA — weightings change per exam version).

The objectives PDF is the canonical checklist for exact wording and every listed term — see how to get it. These pages follow it but do not replace it.

Learning objectives

  • Identify the four CS0-003 domains, their weightings, and their themes.
  • Use the weightings to prioritise study time (Security Operations is the largest, at 33%).
  • Navigate to the per-domain page written to the official objectives.

Domain index

# Domain Weight Theme (one line)
1 Security Operations 33% System/network architecture, analyzing indicators of malicious activity, detection tooling, threat intel & hunting, SOC efficiency/SOAR
2 Vulnerability Management 30% Scanning, scoring (CVSS), validation, prioritization, remediation, and secure-coding/attack-surface controls
3 Incident Response and Management 20% Attack frameworks, the IR lifecycle, detection & analysis, containment/eradication/recovery, post-incident activity
4 Reporting and Communication 17% Vulnerability and incident reporting, metrics/KPIs, stakeholder communication, and compliance 
flowchart LR
    Idx(["CS0-003 domains<br/>(by weight)"])
    Idx --> D1["1 · Security Operations<br/>33% — largest"]
    Idx --> D2["2 · Vulnerability<br/>Management — 30%"]
    Idx --> D3["3 · Incident Response<br/>& Management — 20%"]
    Idx --> D4["4 · Reporting &<br/>Communication — 17%"]

How to use these pages

  • Prioritise by weight. Domain 1 (Security Operations, 33%) and Domain 2 (Vulnerability Management, 30%) together are ~63% of the exam — the technical detection-and-remediation core. Start there. Domains 3 and 4 cover the process and people side (running an incident, reporting it) and together are still over a third of the exam, so do not skip them.
  • Pair with the objectives PDF. Track each sub-objective against the official list; these pages are written to those objectives but the PDF is the authoritative checklist — see exam-and-objectives.md.
  • Cross-reference the offensive view. Where this hub covers attacks defensively, the CEH modules cover the same techniques from the attacker's side; the attack-to-defense matrix, protocols reference, and repo glossary reinforce shared fundamentals.

Where to go next

Sources