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+# Detection Requirements
+
+## Overview
+
+Covers deciding what to detect and in what order: where detection ideas come from, how to turn them into actionable requirements, and how to prioritize them against threats and the organization's actual risk and exposure.
+
+## Learning Objectives
+
+By the end of this module, learners should be able to:
+
+- Write a detection requirement that states the behavior, required data, triggering conditions, context, and success criteria.
+- Identify where detection ideas come from, and evaluate an idea's relevance to the environment.
+- Extract detection requirements from a detection threat model.
+- Use asset criticality, exposure, and vulnerability state to shape the priority and scope of a requirement.
+- Determine whether a requirement can be met with available telemetry within organizational constraints.
+- Prioritize requirements and communicate the decisions in terms of risk reduction.
+
+## Prerequisites
+
+- Module 01: Detection Engineering Foundations
+- Module 02: Telemetry & Data
+
+## Lessons
+
+### 1. What A Detection Requirement Is
+
+**Learning Objectives**
+
+- Explain why requirements come before design, and why a blocked requirement is a valid outcome.
+- Scope a vague detection request into a defined problem.
+- Write a requirement that states the behavior, data, conditions, context, and success criteria.
+
+**Key Topics**
+
+- Starting from the problem, not a query
+- Scoping questions (who, which systems, what data, what priority, what response)
+- Visibility problems vs. detection problems
+- Minimum contents of a requirement
+- Verify, don't assume
+- Requirements vs. hypotheses and designs
+
+**Out of scope**
+
+- Sources of detection ideas (Lesson 2)
+- Feasibility in depth (Lesson 5)
+- Hypotheses and design (Module 04)
+
+### 2. Sources of Detection Ideas
+
+**Learning Objectives**
+
+- Identify the sources detection ideas come from.
+- Evaluate an idea's relevance to the environment.
+- Explain why every request goes through the same intake.
+
+**Key Topics**
+
+- Threat intelligence
+- Incidents and post-incident reviews
+- Red team, penetration test, and purple team findings
+- Threat hunting
+- ATT&CK as a source
+- Compliance and stakeholder requests
+- News driven requests
+
+**Out of scope**
+
+- Researching a behavior (Module 04)
+- Running a threat intelligence or threat hunting program
+- Prioritizing ideas (Lesson 6)
+
+### 3. Threat-Informed Requirements
+
+**Learning Objectives**
+
+- Build a detection threat model.
+- Translate threat scenarios into expected behaviors and required telemetry.
+- Use ATT&CK to provide structure and find gaps without using it as a checklist.
+- Derive requirements from a threat model.
+
+**Key Topics**
+
+- Why "detect everything" fails
+- Threat modeling for detection
+- Who attacks, what they want, how they get in, what they do next, and what they leave behind
+- Threats to behaviors to telemetry to gaps to requirements
+- ATT&CK as a tool
+- Living threat models
+
+**Out of scope**
+
+- Asset and exposure context (Lesson 4)
+- Coverage analysis of existing detections (Module 04)
+- Researching a behavior in depth (Module 04)
+
+### 4. Risk & Exposure Context
+
+**Learning Objectives**
+
+- Explain how asset criticality, exposure, and vulnerability state change the priority of a detection requirement.
+- Use vulnerability intelligence (KEV, EPSS, CVSS) as inputs to detection requirements and describe the limits of each.
+- Identify when detection should act as a compensating control for risk that cannot be remediated in the near term.
+- Scope a compensating detection requirement to the asset's exposure and its remediation timeline.
+
+**Key Topics**
+
+- Asset criticality: business impact, crown-jewel systems, and why the same technique warrants different priority on different assets
+- Attack surface and exposure: internet-facing versus internal, identity exposure, and third-party or vendor access
+- Vulnerability state as a detection input:
+  - CISA KEV: confirmed exploitation in the wild
+  - EPSS: likelihood of exploitation
+  - CVSS: severity rather than risk, and why it should not drive priority alone
+- Detection as a compensating control:
+  - End-of-life and end-of-support systems the business depends on, such as point-of-sale systems and legacy reporting applications or databases
+  - Why remediation is often deferred: upgrade cost, operational downtime, and vendor dependencies
+  - Treating detection as an interim control while remediation remains a long-term goal
+- Missing or failed preventive controls: where prevention is absent, detection carries more weight
+- Requirement expiry: re-evaluating or retiring exposure-driven requirements when the exposure is remediated or the asset is decommissioned
+- Sources of exposure context: vulnerability scanning, asset inventory and CMDB data, attack surface management, and cloud posture management
+
+**Out of scope**
+
+- Operating a vulnerability management program (scanning cadence, patching workflows, SLAs)
+- Combining risk factors into a final priority (Lesson 6)
+- Telemetry required to observe exploitation (Module 02)
+- Building exploitation detections (Module 05)
+
+### 5. Feasibility
+
+**Learning Objectives**
+
+- Map a requirement to the log sources, events, and fields it needs.
+- Rate a requirement's feasibility.
+- Identify platform, organizational, and compliance constraints.
+- Record an unsupported requirement as a telemetry gap.
+
+**Key Topics**
+
+- Environment assessment (Module 02) vs. per-requirement feasibility
+- Field level data source mapping
+- Whether the requirement needs a baseline
+- Platform, organizational, and compliance constraints
+- Whether the SOC can act on the result
+- Tracking blocked requirements
+
+**Out of scope**
+
+- Assessing log source quality (Module 02)
+- Closing telemetry gaps (Module 02)
+- Detection design (Module 04)
+
+### 6. Prioritization
+
+**Learning Objectives**
+
+- Combine threat, impact, exposure, feasibility, and effort into a defensible priority for a detection requirement.
+- Evaluate the strengths and failure modes of common prioritization approaches.
+- Decide when a risk should be addressed through detection, prevention, or explicit acceptance.
+- Communicate prioritization decisions to stakeholders in terms of risk reduction.
+
+**Key Topics**
+
+- Prioritization inputs: threat relevance, potential impact, asset exposure, telemetry feasibility, and engineering effort
+- Prioritization approaches:
+  - Qualitative tiers (high / medium / low)
+  - Weighted scoring models
+  - Threat-driven ranking (for example, prevalence of techniques in relevant threat activity)
+  - Coverage-gap-driven ranking
+- Failure modes:
+  - Headline-driven priority: high-profile news creating pressure to act on threats with little relevance to the environment
+  - Severity over exposure: letting a single input such as CVSS outrank actual exposure and exploitability
+  - Remediation-only planning: relying on a long remediation effort that later stalls on an undiscovered dependency, with no interim detection in place
+  - False precision in scoring models, and prioritizing what is easy to build over what matters
+- Detect, prevent, or accept: when detection is the right investment and when the better answer is a preventive control or documented risk acceptance
+- Re-prioritization triggers: new threat intelligence, incidents, environment changes, and remediated exposure
+- Explaining priority to stakeholders: tying decisions to risk reduction rather than rule counts, and grounding responses to headline threats in actual exposure
+
+**Out of scope**
+
+- Detailed treatment of exposure and asset risk inputs (Lesson 4)
+- Assessing telemetry availability (Lesson 5)
+- Program-level backlog management, capacity planning, and metrics (Module 10)
+
+## Boundaries
+
+| Topic | This module | Adjacent module(s) |
+| --- | --- | --- |
+| ATT&CK coverage | Using coverage gaps to prioritize | 04 Detection Design (mapping and coverage analysis) |
+| Telemetry feasibility | Whether a specific requirement can be met | 02 Telemetry & Data (assessing and improving sources) |
+| Threat research | Intake and turning research into requirements | 04 Detection Design (researching the behavior to detect) |
+| Backlog and intake process | Per-requirement intake and prioritization | 10 Detection Program Engineering (program level) |
+| Vulnerability management | Vulnerability state as a detection input | Operating a vulnerability management program is not covered in Core |
+| Baselines | Identifying when a requirement needs one | 02 Telemetry & Data (establishing baselines); 04 Detection Design (using them) |
+| Hypotheses and design | Not covered | 04 Detection Design |
+
+## Labs
+
+N/A
+
+## Datasets
+
+N/A
+
+## References
+
+### Detection Requirements and Sources
+
+- [Alerting and Detection Strategies Framework](https://github.com/palantir/alerting-detection-strategy-framework), Palantir Incident Response Team, 2017.
+- [SP 800-61 Rev. 3: Incident Response Recommendations and Considerations for Cybersecurity Risk Management](https://csrc.nist.gov/pubs/sp/800/61/r3/final), Alexander Nelson, Sanjay Rekhi, Murugiah Souppaya, and Karen Scarfone, National Institute of Standards and Technology, 2025. DOI: 10.6028/NIST.SP.800-61r3.
+- [The NIST Cybersecurity Framework (CSF) 2.0](https://www.nist.gov/publications/nist-cybersecurity-framework-csf-20), National Institute of Standards and Technology, 2024. DOI: 10.6028/NIST.CSWP.29.
+
+### Threat-Informed Requirements
+
+- [MITRE ATT&CK, v20.0](https://attack.mitre.org/), The MITRE Corporation, 2026. Retrieved 2026-11-01.
+- [The Design and Philosophy of MITRE ATT&CK](https://attack.mitre.org/docs/ATTACK_Design_and_Philosophy_March_2020.pdf), Blake E. Strom et al., The MITRE Corporation, 2020.
+- [ATT&CK Detection Strategies](https://attack.mitre.org/detectionstrategies/), The MITRE Corporation, n.d. Retrieved 2026-11-01.
+- [Top ATT&CK Techniques](https://ctid.mitre.org/projects/top-attack-techniques), MITRE Center for Threat-Informed Defense, 2024. Retrieved 2026-11-01.
+
+### Risk and Exposure Context
+
+- [NIST SP 800-30 Rev. 1: Guide for Conducting Risk Assessments](https://csrc.nist.gov/pubs/sp/800/30/r1/final), Joint Task Force Transformation Initiative, National Institute of Standards and Technology, 2012. DOI: 10.6028/NIST.SP.800-30r1.
+- [NIST IR 8286A Rev. 1: Identifying and Estimating Cybersecurity Risk for Enterprise Risk Management](https://csrc.nist.gov/pubs/ir/8286/a/r1/final), Stephen Quinn et al., National Institute of Standards and Technology, 2026.
+- [Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog), Cybersecurity and Infrastructure Security Agency, n.d. Retrieved 2026-11-01.
+- [Exploit Prediction Scoring System](https://www.first.org/epss/), Forum of Incident Response and Security Teams, n.d. Retrieved 2026-11-01.
+- [Common Vulnerability Scoring System, Version 4.0](https://www.first.org/cvss/v4.0/specification-document), Forum of Incident Response and Security Teams, 2023.
+- [Stakeholder-Specific Vulnerability Categorization Guide](https://www.cisa.gov/sites/default/files/publications/cisa-ssvc-guide%20508c.pdf), Cybersecurity and Infrastructure Security Agency, n.d. Retrieved 2026-11-01.
+
+### Feasibility and Prioritization
+
+- [Top ATT&CK Techniques Methodology](https://center-for-threat-informed-defense.github.io/top-attack-techniques/), MITRE Center for Threat-Informed Defense, 2024. Retrieved 2026-11-01.
+- [CISA Cross-Sector Cybersecurity Performance Goals](https://www.cisa.gov/cross-sector-cybersecurity-performance-goals), Cybersecurity and Infrastructure Security Agency, n.d. Retrieved 2026-11-01.
+
+## AI Assistance
+
+Research
diff --git a/core/03-detection-requirements/module-metadata.yml b/core/03-detection-requirements/module-metadata.yml
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+title: Detection Requirements
+slug: detection-requirements
+status: draft # draft | in-review | reviewed | stable | needs-update | deprecated
+version: 0.1
+
+summary: >
+  Covers deciding what to detect and in what order: where detection ideas
+  come from, how to turn them into actionable requirements, and how to
+  prioritize them against threats and the organization's actual risk and
+  exposure.
+
+learning_objectives:
+  - Write a detection requirement that states the behavior, required data, triggering conditions, context, and success criteria.
+  - Identify where detection ideas come from, and evaluate an idea's relevance to the environment.
+  - Extract detection requirements from a detection threat model.
+  - Use asset criticality, exposure, and vulnerability state to shape the priority and scope of a requirement.
+  - Determine whether a requirement can be met with available telemetry within organizational constraints.
+  - Prioritize requirements and communicate the decisions in terms of risk reduction.
+
+prerequisites:
+  - Module 01 Detection Engineering Foundations
+  - Module 02 Telemetry & Data
+
+authors:
+  - Treyrob3
+  - mndtrcks
+
+reviewers: [] # GitHub handles (without @) of independent approving reviewers
+
+maintainers:
+  - mndtrcks
+  - Treyrob3
+
+ai_assistance: >
+  research
+
+last_reviewed: null # YYYY-MM-DD, set by a maintainer on approval
+
+related_tracks: []
+
+related_labs: []
+
+related_datasets: []