Tailscale Premium Subnet router throughput anomaly

let baselineDays = 7d;
let recent = 1h;
let multiplier = 3.0;
let recentTraffic =
    Tailscale_Network_CL
    | where TimeGenerated > ago(recent)
    | where HasSubnetTraffic
    | mv-expand t = SubnetTraffic
    | extend Bytes = tolong(t.txBytes) + tolong(t.rxBytes)
    | summarize RecentBytes = sum(Bytes) by NodeId, SrcNodeName, SrcUser, SrcOs, SrcTags=tostring(SrcTags);
let baseline =
    Tailscale_Network_CL
    | where TimeGenerated between (ago(baselineDays + recent) .. ago(recent))
    | where HasSubnetTraffic
    | mv-expand t = SubnetTraffic
    | extend Bytes = tolong(t.txBytes) + tolong(t.rxBytes)
    | summarize TotalBaselineBytes = sum(Bytes) by NodeId
    | extend BaselineHourlyBytes = TotalBaselineBytes / 168.0;
recentTraffic
| join kind=inner baseline on NodeId
| where RecentBytes > BaselineHourlyBytes * multiplier
| extend Multiplier = round(RecentBytes / BaselineHourlyBytes, 1), RecentMB = round(RecentBytes / 1024.0 / 1024.0, 2), BaselineHourlyMB = round(BaselineHourlyBytes / 1024.0 / 1024.0, 2)
| project NodeId, SrcNodeName, SrcUser, SrcOs, SrcTags, RecentMB, BaselineHourlyMB, Multiplier
| order by Multiplier desc

incidentConfiguration:
  groupingConfiguration:
    lookbackDuration: P1D
    reopenClosedIncident: false
    matchingMethod: AllEntities
    enabled: true
  createIncident: true
name: 'Tailscale Premium: Subnet router throughput anomaly'
triggerOperator: gt
query: |
  let baselineDays = 7d;
  let recent = 1h;
  let multiplier = 3.0;
  let recentTraffic =
      Tailscale_Network_CL
      | where TimeGenerated > ago(recent)
      | where HasSubnetTraffic
      | mv-expand t = SubnetTraffic
      | extend Bytes = tolong(t.txBytes) + tolong(t.rxBytes)
      | summarize RecentBytes = sum(Bytes) by NodeId, SrcNodeName, SrcUser, SrcOs, SrcTags=tostring(SrcTags);
  let baseline =
      Tailscale_Network_CL
      | where TimeGenerated between (ago(baselineDays + recent) .. ago(recent))
      | where HasSubnetTraffic
      | mv-expand t = SubnetTraffic
      | extend Bytes = tolong(t.txBytes) + tolong(t.rxBytes)
      | summarize TotalBaselineBytes = sum(Bytes) by NodeId
      | extend BaselineHourlyBytes = TotalBaselineBytes / 168.0;
  recentTraffic
  | join kind=inner baseline on NodeId
  | where RecentBytes > BaselineHourlyBytes * multiplier
  | extend Multiplier = round(RecentBytes / BaselineHourlyBytes, 1), RecentMB = round(RecentBytes / 1024.0 / 1024.0, 2), BaselineHourlyMB = round(BaselineHourlyBytes / 1024.0 / 1024.0, 2)
  | project NodeId, SrcNodeName, SrcUser, SrcOs, SrcTags, RecentMB, BaselineHourlyMB, Multiplier
  | order by Multiplier desc
queryFrequency: 1h
description: |
  Identifies when a subnet router (gateway node bridging the tailnet to an on-prem or cloud subnet) handles 3x or more its 7-day baseline traffic in the last hour. Spikes can indicate exfiltration or scanning. Requires Tailscale Premium or Enterprise.
id: a5b6c7d8-5e6f-7a8b-9c0d-1e2f3a4b5c6d
triggerThreshold: 0
queryPeriod: 8d
version: 1.0.0
kind: Scheduled
status: Available
severity: Low
requiredDataConnectors:
- connectorId: TailscalePremiumCCF
  dataTypes:
  - Tailscale_Network_CL
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Tailscale%20%28CCF%29/Analytic%20Rules/TailscalePremiumSubnetRouterThroughputAnomaly.yaml
relevantTechniques:
- T1572
- T1041
tactics:
- Exfiltration
- CommandAndControl
entityMappings:
- fieldMappings:
  - identifier: HostName
    columnName: SrcNodeName
  entityType: Host
- fieldMappings:
  - identifier: FullName
    columnName: SrcUser
  entityType: Account

{
  "$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/a5b6c7d8-5e6f-7a8b-9c0d-1e2f3a4b5c6d')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/a5b6c7d8-5e6f-7a8b-9c0d-1e2f3a4b5c6d')]",
      "properties": {
        "alertRuleTemplateName": "a5b6c7d8-5e6f-7a8b-9c0d-1e2f3a4b5c6d",
        "customDetails": null,
        "description": "Identifies when a subnet router (gateway node bridging the tailnet to an on-prem or cloud subnet) handles 3x or more its 7-day baseline traffic in the last hour. Spikes can indicate exfiltration or scanning. Requires Tailscale Premium or Enterprise.\n",
        "displayName": "Tailscale Premium: Subnet router throughput anomaly",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "SrcNodeName",
                "identifier": "HostName"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "SrcUser",
                "identifier": "FullName"
              }
            ]
          }
        ],
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "lookbackDuration": "P1D",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Tailscale%20%28CCF%29/Analytic%20Rules/TailscalePremiumSubnetRouterThroughputAnomaly.yaml",
        "query": "let baselineDays = 7d;\nlet recent = 1h;\nlet multiplier = 3.0;\nlet recentTraffic =\n    Tailscale_Network_CL\n    | where TimeGenerated > ago(recent)\n    | where HasSubnetTraffic\n    | mv-expand t = SubnetTraffic\n    | extend Bytes = tolong(t.txBytes) + tolong(t.rxBytes)\n    | summarize RecentBytes = sum(Bytes) by NodeId, SrcNodeName, SrcUser, SrcOs, SrcTags=tostring(SrcTags);\nlet baseline =\n    Tailscale_Network_CL\n    | where TimeGenerated between (ago(baselineDays + recent) .. ago(recent))\n    | where HasSubnetTraffic\n    | mv-expand t = SubnetTraffic\n    | extend Bytes = tolong(t.txBytes) + tolong(t.rxBytes)\n    | summarize TotalBaselineBytes = sum(Bytes) by NodeId\n    | extend BaselineHourlyBytes = TotalBaselineBytes / 168.0;\nrecentTraffic\n| join kind=inner baseline on NodeId\n| where RecentBytes > BaselineHourlyBytes * multiplier\n| extend Multiplier = round(RecentBytes / BaselineHourlyBytes, 1), RecentMB = round(RecentBytes / 1024.0 / 1024.0, 2), BaselineHourlyMB = round(BaselineHourlyBytes / 1024.0 / 1024.0, 2)\n| project NodeId, SrcNodeName, SrcUser, SrcOs, SrcTags, RecentMB, BaselineHourlyMB, Multiplier\n| order by Multiplier desc\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P8D",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl",
          "Exfiltration"
        ],
        "techniques": [
          "T1041",
          "T1572"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}