{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/c1d2e3f4-1a2b-3c4d-5e6f-7a8b9c0d1e2f')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/c1d2e3f4-1a2b-3c4d-5e6f-7a8b9c0d1e2f')]",
      "properties": {
        "alertRuleTemplateName": "c1d2e3f4-1a2b-3c4d-5e6f-7a8b9c0d1e2f",
        "customDetails": null,
        "description": "Identifies when a node sends traffic via an exit node not used in the prior 7-day baseline. First-seen exit destinations from a node may indicate routing-policy drift, data exfiltration, or compromise.",
        "description-detailed": "Identifies when a node sends traffic via an exit node not used in the prior 7-day baseline. First-seen exit destinations from a specific source may indicate unsanctioned egress, a compromised node pivoting, or a policy misconfiguration. Requires Tailscale Premium or Enterprise.\n",
        "displayName": "Tailscale Premium: Unexpected exit-node egress",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "SrcNodeName",
                "identifier": "HostName"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "SrcUser",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "Src",
                "identifier": "Address"
              }
            ]
          }
        ],
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "lookbackDuration": "PT5H",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Tailscale%20%28CCF%29/Analytic%20Rules/TailscalePremiumUnexpectedExitNodeEgress.yaml",
        "query": "let baseline = 7d;\nlet recent = 1h;\nlet recentEgress =\n    Tailscale_Network_CL\n    | where TimeGenerated > ago(recent)\n    | where HasExitTraffic\n    | mv-expand t = ExitTraffic\n    | extend Src = tostring(t.src), ExitDst = tostring(t.dst), Bytes = tolong(t.txBytes) + tolong(t.rxBytes)\n    | summarize FirstSeen = min(TimeGenerated), TotalBytes = sum(Bytes) by NodeId, SrcNodeName, SrcUser, SrcOs, Src, ExitDst;\nlet baselineEgress =\n    Tailscale_Network_CL\n    | where TimeGenerated between (ago(baseline + recent) .. ago(recent))\n    | where HasExitTraffic\n    | mv-expand t = ExitTraffic\n    | extend Src = tostring(t.src), ExitDst = tostring(t.dst)\n    | distinct NodeId, Src, ExitDst;\nrecentEgress\n| join kind=leftanti baselineEgress on NodeId, Src, ExitDst\n| extend TotalMB = round(TotalBytes / 1024.0 / 1024.0, 2)\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl",
          "Exfiltration"
        ],
        "techniques": [
          "T1041",
          "T1090"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}