Ngrok Reverse Proxy on Network ASIM DNS Solution

// Define a list of Ngrok domains
let NgrokDomains = dynamic(["ngrok.com", "ngrok.io", "ngrok", "tunnel.com", "korgn", "lennut.com"]);
// Query the _Im_Dns function for the past 1 hour
_Im_Dns(starttime=ago(1h))
| where isnotempty(DnsQuery) // Filter out empty DNS queries
| where DnsQuery has_any (NgrokDomains) // Filter DNS queries that match any of the Ngrok domains
| summarize Starttime = min(EventStartTime),Endtime=max(EventEndTime),EventsCount=sum(EventCount),EventResults=make_set(EventResult,4) by DnsQuery, Domain, SrcIpAddr, Dvc
// Summarize the data by Domain, DNS query, source IP address, and device Dvc

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/NgrokReverseProxyOnNetwork.yaml
status: Available
id: 50b0dfb7-2c94-4eaf-a332-a5936d78c263
query: |
  // Define a list of Ngrok domains
  let NgrokDomains = dynamic(["ngrok.com", "ngrok.io", "ngrok", "tunnel.com", "korgn", "lennut.com"]);
  // Query the _Im_Dns function for the past 1 hour
  _Im_Dns(starttime=ago(1h))
  | where isnotempty(DnsQuery) // Filter out empty DNS queries
  | where DnsQuery has_any (NgrokDomains) // Filter DNS queries that match any of the Ngrok domains
  | summarize Starttime = min(EventStartTime),Endtime=max(EventEndTime),EventsCount=sum(EventCount),EventResults=make_set(EventResult,4) by DnsQuery, Domain, SrcIpAddr, Dvc
  // Summarize the data by Domain, DNS query, source IP address, and device Dvc  
tags:
- SchemaVersion: 0.1.6
  Schema: ASimDns
description: |
    'This detection identifies the top four Ngrok domains from DNS resolution. Ngrok reverse proxy can bypass network defense. While not inherently harmful, it has been used for malicious activities recently.'
name: Ngrok Reverse Proxy on Network (ASIM DNS Solution)
relevantTechniques:
- T1572
- T1090
- T1102
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
- entityType: DNS
  fieldMappings:
  - identifier: DomainName
    columnName: Domain
triggerThreshold: 0
severity: Medium
requiredDataConnectors: []
eventGroupingSettings:
  aggregationKind: AlertPerResult
queryFrequency: 1h
queryPeriod: 1h
version: 1.0.0
kind: Scheduled
tactics:
- CommandAndControl
triggerOperator: gt

{
  "$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/50b0dfb7-2c94-4eaf-a332-a5936d78c263')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/50b0dfb7-2c94-4eaf-a332-a5936d78c263')]",
      "properties": {
        "alertRuleTemplateName": "50b0dfb7-2c94-4eaf-a332-a5936d78c263",
        "customDetails": null,
        "description": "'This detection identifies the top four Ngrok domains from DNS resolution. Ngrok reverse proxy can bypass network defense. While not inherently harmful, it has been used for malicious activities recently.'\n",
        "displayName": "Ngrok Reverse Proxy on Network (ASIM DNS Solution)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "DNS",
            "fieldMappings": [
              {
                "columnName": "Domain",
                "identifier": "DomainName"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/NgrokReverseProxyOnNetwork.yaml",
        "query": "// Define a list of Ngrok domains\nlet NgrokDomains = dynamic([\"ngrok.com\", \"ngrok.io\", \"ngrok\", \"tunnel.com\", \"korgn\", \"lennut.com\"]);\n// Query the _Im_Dns function for the past 1 hour\n_Im_Dns(starttime=ago(1h))\n| where isnotempty(DnsQuery) // Filter out empty DNS queries\n| where DnsQuery has_any (NgrokDomains) // Filter DNS queries that match any of the Ngrok domains\n| summarize Starttime = min(EventStartTime),Endtime=max(EventEndTime),EventsCount=sum(EventCount),EventResults=make_set(EventResult,4) by DnsQuery, Domain, SrcIpAddr, Dvc\n// Summarize the data by Domain, DNS query, source IP address, and device Dvc\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "tags": [
          {
            "Schema": "ASimDns",
            "SchemaVersion": "0.1.6"
          }
        ],
        "techniques": [
          "T1090",
          "T1102",
          "T1572"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}