building-cloud-siem-with-sentinel

Building Cloud SIEM with Sentinel

When to Use

• When establishing a centralized security operations center for multi-cloud environments
• When migrating from legacy SIEM platforms (Splunk, QRadar) to cloud-native architecture
• When building automated incident response workflows for cloud-specific threats
• When performing large-scale threat hunting across petabytes of security telemetry
• When integrating threat intelligence feeds with cloud security log analysis

Do not use for AWS-only environments where Security Hub and GuardDuty suffice, for endpoint detection requiring EDR capabilities (use Defender for Endpoint), or for compliance posture monitoring (see building-cloud-security-posture-management).

Prerequisites

• Azure subscription with Microsoft Sentinel enabled on a Log Analytics workspace
• Data connector permissions for target log sources (AWS CloudTrail, Azure Activity, GCP)
• Logic Apps or Azure Functions for automated response playbooks
• KQL (Kusto Query Language) proficiency for writing detection rules and hunting queries

Workflow

Step 1: Provision Sentinel Workspace and Data Connectors

Create a Log Analytics workspace optimized for security data and enable data connectors for multi-cloud ingestion.

# Create Log Analytics workspace
az monitor log-analytics workspace create \
  --resource-group security-rg \
  --workspace-name sentinel-workspace \
  --location eastus \
  --retention-time 365 \
  --sku PerGB2018

# Enable Microsoft Sentinel on the workspace
az sentinel onboarding-state create \
  --resource-group security-rg \
  --workspace-name sentinel-workspace

# Enable AWS CloudTrail connector
az sentinel data-connector create \
  --resource-group security-rg \
  --workspace-name sentinel-workspace \
  --data-connector-id aws-cloudtrail \
  --kind AmazonWebServicesCloudTrail \
  --aws-cloud-trail-data-connector '{
    "awsRoleArn": "arn:aws:iam::123456789012:role/SentinelCloudTrailRole",
    "dataTypes": {"logs": {"state": "Enabled"}}
  }'

# Enable Azure AD sign-in and audit logs
az sentinel data-connector create \
  --resource-group security-rg \
  --workspace-name sentinel-workspace \
  --data-connector-id azure-ad \
  --kind AzureActiveDirectory \
  --azure-active-directory '{
    "dataTypes": {
      "alerts": {"state": "Enabled"},
      "signinLogs": {"state": "Enabled"},
      "auditLogs": {"state": "Enabled"}
    }
  }'