building-cloud-siem-with-sentinel

Files (4)

• LICENSE
• SKILL.md
• api-reference.md · references/
• agent.py · scripts/

SKILL.md (first lines)

# 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.

```powershell
# 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"}
    }
  }'
```

### Step 2: Write KQL Detection Rules

Create analytics rules using Kusto Query Language to detect cloud-specific threats. Map each rule to MITRE ATT&CK techniques.

```kql
// Detect impossible travel - sign-ins from geographically distant locations
let timeframe = 1h;
let distance_threshold = 500; // km
SigninLogs
| where TimeGenerated > ago(timeframe)
| where ResultType == 0 // Successful sign-ins only
| project TimeGenerated, UserPrincipalName, IPAddress, Location,
          Latitude = toreal(LocationDetails.geoCoordinates.latitude),
          Longitude = toreal(LocationDetails.geoCoordinates.longitude)
| sort by UserPrincipalName asc, TimeGenerated asc
| extend PrevLatitude = prev(Latitude, 1), PrevLongitude = prev(Longitude, 1),
         PrevTime = prev(TimeGenerated, 1), PrevUser = prev(UserPrincipalName, 1)
| where UserPrincipalName == PrevUser
| extend TimeDiff = datetime_diff('minute', TimeGenerated, PrevTime)
| where TimeDiff < 60
| extend Distance = geo_distance_2points(Longitude, Latitude, PrevLongitude, PrevLatitude) / 1000
| where Distance > distance_threshold
| project TimeGenerated, UserPrincipalName, IPAddress, Location, Distance, TimeDiff
```

```kql
// Detect AWS IAM credential abuse from CloudTrail
AWSCloudTrail
| where TimeGenerated > ago(24h)
| where EventName in ("ConsoleLogin", "AssumeRole", "GetSessionToken")
| where ErrorCode == ""
| summarize LoginCount = count(), DistinctIPs = dcount(SourceIpAddress),
            IPList = make_set(SourceIpAddress, 10)
            by UserIdentityArn, bin(TimeGenerated, 1h)
| where DistinctIPs > 3
| project TimeGenerated, UserIdentityArn, LoginCount, DistinctIPs, IPList
```

```kql
// Detect mass S3 object deletion (potential ransomware)
AWSCloudTrail
| where TimeGenerated > ago(1h)
| where EventName == "DeleteObject" or EventName == "DeleteObjects"
| summarize DeleteCount = count(), BucketsAffected = dcount(RequestParameters_bucketName)
            by UserIdentityArn, bin(TimeGenerated, 10m)
| where DeleteCount > 100
| project TimeGenerated, UserIdentityArn, DeleteCount, BucketsAffected
```

### Step 3: Build SOAR Playbooks with Logic Apps

Create automated response playbooks that execute when analytics rules trigger incidents. Common actions include blocking users, isolating resources, and enriching alerts with threat intelligence.

```json

From mukul975/Anthropic-Cybersecurity-Skills, Apache-2.0.

More from mukul975/Anthropic-Cybersecurity-Skills