Azure Diagnostic Settings Deleted

AnalysisType: rule
Filename: azure_diagnostic_settings_deleted.py
RuleID: "Azure.MonitorActivity.DiagnosticSettings.Deleted"
DisplayName: "Azure Diagnostic Settings Deleted"
Enabled: true
LogTypes:
  - Azure.MonitorActivity
Severity: Medium
Description: >
  Detects when Azure diagnostic settings are deleted. Deleting diagnostic settings disables logging and monitoring, which is a common technique to hide malicious activity.
Reports:
  MITRE ATT&CK:
    - TA0005:T1562.008 # Defense Evasion: Impair Defenses - Disable Cloud Logs
Tags:
  - Defense Evasion
  - Impair Defenses
  - Disable Cloud Logs
Runbook: |
  1. Query Azure Monitor Activity logs for all diagnostic settings and monitoring operations by the callerIpAddress in the 24 hours before and after this alert to identify if multiple resources are being de-monitored
  2. Check if the source IP is associated with known cloud providers, VPN services, or corporate network ranges using threat intelligence
  3. Search for other Azure resource modifications or suspicious activities from the same user or IP in the past 7 days to assess if this is part of a defense evasion campaign
Reference: https://docs.datadoghq.com/security/default_rules/apn-0ib-a6f/
SummaryAttributes:
  - resourceId
  - callerIpAddress
  - correlationId
Tests:
  - Name: Diagnostic Settings Deleted
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T10:30:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Storage/storageAccounts/mystorageaccount/providers/Microsoft.Insights/diagnosticSettings/mydiagnostics",
        "operationName": "Microsoft.Insights/diagnosticSettings/delete",
        "operationVersion": "2021-05-01",
        "category": "Administrative",
        "resultType": "Success",
        "resultSignature": "200",
        "callerIpAddress": "1.1.1.1",
        "correlationId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",

        "location": "eastus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Case Insensitive Match
    ExpectedResult: true
    Log:
      {
        "time": "2024-12-17T11:45:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/prod-rg/providers/Microsoft.KeyVault/vaults/prodvault/providers/Microsoft.Insights/diagnosticSettings/logging",
        "operationName": "microsoft.insights/diagnosticsettings/delete",
        "operationVersion": "2021-05-01",
        "category": "Administrative",
        "resultType": "Succeeded",
        "callerIpAddress": "1.2.3.4",
        "correlationId": "f9e8d7c6-b5a4-3210-9876-fedcba098765",

        "location": "westus",
        "tenantId": "87654321-4321-4321-4321-111111111111"
      }
  - Name: Different Operation
    ExpectedResult: false
    Log:
      {
        "time": "2024-12-17T13:30:00.0000000Z",
        "resourceId": "/subscriptions/12345678-1234-1234-1234-123456789abc/resourceGroups/myresourcegroup/providers/Microsoft.Insights/diagnosticSettings/mydiagnostics",
        "operationName": "Microsoft.Insights/diagnosticSettings/write",
        "operationVersion": "2021-05-01",
        "category": "Administrative",
        "resultType": "Success",
        "callerIpAddress": "203.0.113.75",
        "correlationId": "d4e5f6a7-b8c9-0123-def0-234567890123",

        "location": "centralus",
        "tenantId": "87654321-4321-4321-4321-210987654321"
      }