Tailscale Exit node advertised or approved

Tailscale_Audit_CL
      | where Action contains "EXIT" or tostring(New.advertisedExitNode) == "true" or tostring(New.allowedExitNode) == "true"
      | extend ActorLogin = tostring(Actor.loginName)
      | extend NodeName = tostring(Target.name)
      | extend NodeId = tostring(Target.id)
      | project TimeGenerated, ActorLogin, Action, NodeName, NodeId, Origin, New, Old

incidentConfiguration:
  groupingConfiguration:
    lookbackDuration: PT5H
    reopenClosedIncident: false
    matchingMethod: AllEntities
    enabled: true
  createIncident: true
name: 'Tailscale: Exit node advertised or approved'
triggerOperator: gt
query: |
  Tailscale_Audit_CL
        | where Action contains "EXIT" or tostring(New.advertisedExitNode) == "true" or tostring(New.allowedExitNode) == "true"
        | extend ActorLogin = tostring(Actor.loginName)
        | extend NodeName = tostring(Target.name)
        | extend NodeId = tostring(Target.id)
        | project TimeGenerated, ActorLogin, Action, NodeName, NodeId, Origin, New, Old
queryFrequency: 30m
description: |
  Identifies when a device starts advertising itself as an exit node, or when an admin approves one. Validate the device and operator - rogue exit nodes can intercept tailnet egress.
id: f42f2906-c8e6-23d0-e48c-0620e50d5510
triggerThreshold: 0
queryPeriod: 30m
version: 1.0.0
kind: Scheduled
status: Available
severity: Low
requiredDataConnectors:
- connectorId: TailscaleCCF
  dataTypes:
  - Tailscale_Audit_CL
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Tailscale%20%28CCF%29/Analytic%20Rules/TailscaleExitnodeadvertisedorapproved.yaml
relevantTechniques:
- T1090
tactics:
- CommandAndControl
- Exfiltration
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: ActorLogin
  entityType: Account
- fieldMappings:
  - identifier: HostName
    columnName: NodeName
  entityType: Host

{
  "$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/f42f2906-c8e6-23d0-e48c-0620e50d5510')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/f42f2906-c8e6-23d0-e48c-0620e50d5510')]",
      "properties": {
        "alertRuleTemplateName": "f42f2906-c8e6-23d0-e48c-0620e50d5510",
        "customDetails": null,
        "description": "Identifies when a device starts advertising itself as an exit node, or when an admin approves one. Validate the device and operator - rogue exit nodes can intercept tailnet egress.\n",
        "displayName": "Tailscale: Exit node advertised or approved",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "ActorLogin",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "NodeName",
                "identifier": "HostName"
              }
            ]
          }
        ],
        "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/TailscaleExitnodeadvertisedorapproved.yaml",
        "query": "Tailscale_Audit_CL\n      | where Action contains \"EXIT\" or tostring(New.advertisedExitNode) == \"true\" or tostring(New.allowedExitNode) == \"true\"\n      | extend ActorLogin = tostring(Actor.loginName)\n      | extend NodeName = tostring(Target.name)\n      | extend NodeId = tostring(Target.id)\n      | project TimeGenerated, ActorLogin, Action, NodeName, NodeId, Origin, New, Old\n",
        "queryFrequency": "PT30M",
        "queryPeriod": "PT30M",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl",
          "Exfiltration"
        ],
        "techniques": [
          "T1090"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}