defender-for-cloud-hardening

Microsoft Defender for Cloud (Hardening)

Microsoft Defender for Cloud is a cloud-native application protection platform (CNAPP) combining CSPM (posture, Secure Score, attack paths) and CWPP (threat protection for servers, containers, databases, storage, APIs, AI) across Azure, AWS, and GCP.

When to use

Assessing and improving cloud security posture, and enabling workload threat protection across a multicloud estate. Use this skill to choose which Defender plans to enable, how to prioritise remediation, and how to operationalise findings.

Do not use this skill for SaaS posture (cloud-app-security-posture), Sentinel SIEM (sentinel), or extending Azure management to on-prem (azure-arc).

Pick the Defender plan by workload

Workload	Plan	Enable when
Subscriptions / accounts (posture)	Foundational CSPM (free)	Always; everywhere
Multicloud + attack paths + agentless scanning	Defender CSPM	Tier 1+ environments
Windows / Linux servers (EDR, file integrity, JIT)	Defender for Servers Plan 2	Production servers
Storage accounts (malware, sensitive-data scanning)	Defender for Storage	Public-facing / sensitive data
AKS / EKS / GKE clusters	Defender for Containers	Any production cluster
SQL, Cosmos DB, open-source DBs	Defender for Databases	Internet-exposed or sensitive
App Service apps	Defender for App Service	Internet-facing apps
Key Vault	Defender for Key Vault	Tier 0 / regulated
APIs behind APIM	Defender for APIs	Public APIs
Azure AI / OpenAI workloads	Defender for AI Services	AI workloads handling org data

Rule of thumb: Foundational CSPM everywhere on day one (it's free). Then enable Defender for Servers Plan 2 + Defender CSPM in production - those two unlock the most value (attack paths, EDR integration). Other plans by risk and budget.

Approach

1. Connect all clouds — Onboard Azure (auto), AWS (connector + CloudFormation), GCP (connector + service account). Without all clouds connected, attack paths can't trace across them. Verify: AWS / GCP connectors show "Connected"; recommendations appearing within 24 hours.

2. Foundational CSPM baseline — Get Secure Score, recommendations mapped to Microsoft Cloud Security Benchmark (MCSB), and asset inventory. Use as the universal baseline. Verify: Secure Score baseline captured for each subscription; recommendation count by severity logged.

3. Enable Defender plans by workload risk — Use the picker table. Don't enable every plan on day one - cost spikes and alert fatigue. Production-first.

4. Tag critical assets so the cloud security graph weights them appropriately — criticality=high, environment=prod, data-classification=sensitive. Attack path analysis uses these to rank. Verify: critical assets tagged consistently; attack paths page shows them weighted.

5. Remediate by attack path, not by raw count — Use attack path analysis to find chains from internet → workload → sensitive asset. Fix the chain breakers first. Secure Score % is a vanity metric without attack-path context. Verify: top 5 attack paths reviewed weekly; chain-breaker fixes tracked separately from generic recommendation count.

6. Enforce with Azure Policy — Drive recommendations via Azure Policy DeployIfNotExists or Audit. Assign workload-owner accountability with governance rules + SLA.

7. Operate — Stream alerts and recommendations to Sentinel for SOC correlation. Use workflow automation (Logic Apps) for auto-response (e.g. open ticket, notify owner).

Guardrails

• Start with foundational CSPM everywhere; enable paid plans where workload risk justifies cost. Don't blanket-enable every Defender plan on every subscription.
• Use attack path analysis to focus effort - Secure Score alone can mislead prioritisation. A 95% Secure Score with one internet-exposed unpatched VM is worse than 80% with no live attack path.
• Tag critical assets so the cloud security graph weights them appropriately. Untagged critical asset = invisible to attack-path prioritisation.
• Don't enable Defender for Servers Plan 2 without Defender for Endpoint license / plan awareness. Cost and EDR-policy coordination matter.
• Recommendations without owners die. Assign via governance rules with a named owner and SLA.
• Sentinel + Defender for Cloud is the operational pair. Posture finds, SIEM correlates with telemetry.

Common anti-patterns

• "Maximise Secure Score by exempting recommendations" - Score goes up; risk stays. Fix, don't exempt.
• "Enable every Defender plan everywhere" - Cost explodes; alert fatigue kills SOC. Production-first, by risk.
• "Remediate top 100 recommendations in order" - Misses attack-path priority. Sort by attack path first.
• "Don't connect AWS / GCP - we'll get to it later" - Cross-cloud attack paths invisible. Connect day one even if you don't enable paid plans there yet.
• "Skip tagging critical assets" - Cloud security graph can't weight risk. Tag.
• "Defender for Cloud is a one-time deployment" - Posture drifts daily; treat as a continuous operations programme.

Example prompts

• Improve my Azure Secure Score in Defender for Cloud.
• Which Defender plans should I enable to protect VMs and containers?
• Use attack path analysis to prioritise remediation.
• Extend CSPM across AWS and GCP with Defender for Cloud.
• Tag critical assets and configure the cloud security graph for risk weighting.
• Stream Defender for Cloud alerts into Sentinel with workflow automation.

Microsoft Learn

• Defender for Cloud overview: https://learn.microsoft.com/azure/defender-for-cloud/defender-for-cloud-introduction
• Secure Score: https://learn.microsoft.com/azure/defender-for-cloud/secure-score-security-controls
• Defender CSPM + attack paths: https://learn.microsoft.com/azure/defender-for-cloud/concept-attack-path
• Connect AWS / GCP: https://learn.microsoft.com/azure/defender-for-cloud/multicloud
• Defender plans pricing: https://learn.microsoft.com/azure/defender-for-cloud/defender-for-cloud-glossary
• Cloud security graph: https://learn.microsoft.com/azure/defender-for-cloud/concept-data-security-posture
• Governance rules: https://learn.microsoft.com/azure/defender-for-cloud/governance-rules
• Workflow automation: https://learn.microsoft.com/azure/defender-for-cloud/workflow-automation